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local-search.xml
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<?xml version="1.0" encoding="utf-8"?>
<search>
<entry>
<title>基于Python的音高分析器</title>
<link href="/2023/02/07/pitch-analys/"/>
<url>/2023/02/07/pitch-analys/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h3 id="前提背景"><a href="#前提背景" class="headerlink" title="前提背景"></a>前提背景</h3><p>之前在B站看到一个分析歌手在各大晚会的歌唱表演是否为假唱，通过分析声音的频率还有连续稳定性来判断，觉得很有意思来研究一下。</p><h3 id="准备工作"><a href="#准备工作" class="headerlink" title="准备工作"></a>准备工作</h3><p>首先找到了tensorflow的Spice声音分析模型，查看了下<a href="https://tensorflow.google.cn/hub/tutorials/spice?hl=zh-cn">官方文档</a>照着示例用了一下，步骤比较繁琐且不易懂，其使用的plotly python生成数据图性能较差生成较慢。</p><p>于是找到了另一个开源库 <a href="https://parselmouth.readthedocs.io/en/stable/">Parselmouth</a>，<br>Parselmouth是Praat软件的 Python 库，Parselmouth 直接访问 Praat 的 C/C++ 代码（这意味着算法及其输出与 Praat 中的完全相同）并提供对程序数据的高效访问，但也提供了一个看起来与任何其他 Python 库没有区别的界面，<br>使用起来效率更高且相对简单易懂。</p><h3 id="基础数据处理"><a href="#基础数据处理" class="headerlink" title="基础数据处理"></a>基础数据处理</h3><p>获取频率</p><figure class="highlight python"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><code class="hljs python">sound = parselmouth.Sound(tmp_name)<br><span class="hljs-comment"># 获取频率数组</span><br>pitch_track = sound.to_pitch().selected_array[<span class="hljs-string">'frequency'</span>]<br></code></pre></td></tr></table></figure><p>计算音高，首先了解了下音高的定义及对应频率算法，参考<a href="https://www.jianshu.com/p/0fc2163cfc50">音高、音名与对应频率</a></p><figure class="highlight python"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br></pre></td><td class="code"><pre><code class="hljs python">pitches = <span class="hljs-built_in">list</span>(pitch_track)<br>A4 = <span class="hljs-number">440</span> <span class="hljs-comment">#以A4为基准频率</span><br>C0 = A4 * <span class="hljs-built_in">pow</span>(<span class="hljs-number">2</span>, -<span class="hljs-number">4.75</span>) <span class="hljs-comment">#计算最低C0音高后面作为对比</span><br>note_names = [<span class="hljs-string">"C"</span>, <span class="hljs-string">"C#"</span>, <span class="hljs-string">"D"</span>, <span class="hljs-string">"D#"</span>, <span class="hljs-string">"E"</span>, <span class="hljs-string">"F"</span>, <span class="hljs-string">"F#"</span>, <span class="hljs-string">"G"</span>, <span class="hljs-string">"G#"</span>, <span class="hljs-string">"A"</span>, <span class="hljs-string">"A#"</span>, <span class="hljs-string">"B"</span>]<br>notes = []<br>times = []<br><span class="hljs-keyword">for</span> i, freq <span class="hljs-keyword">in</span> <span class="hljs-built_in">enumerate</span>(pitches):<br> times.append(i / <span class="hljs-number">100</span>)<br> <span class="hljs-comment"># if freq < 329:</span><br> <span class="hljs-comment"># notes.append(None)</span><br> <span class="hljs-comment"># continue</span><br> <span class="hljs-keyword">if</span> freq == <span class="hljs-number">0.0</span>:<br> notes.append(<span class="hljs-literal">None</span>)<br> <span class="hljs-keyword">continue</span><br> h = <span class="hljs-built_in">round</span>(<span class="hljs-number">12</span> * math.log2(freq / C0))<br> octave = h // <span class="hljs-number">12</span><br> n = h % <span class="hljs-number">12</span><br> minute = <span class="hljs-built_in">int</span>(i / <span class="hljs-number">60</span> / <span class="hljs-number">100</span>)<br> second = <span class="hljs-built_in">round</span>(i / <span class="hljs-number">100</span> % <span class="hljs-number">60</span>, <span class="hljs-number">1</span>)<br> note = note_names[n] + <span class="hljs-built_in">str</span>(octave) + <span class="hljs-string">'-'</span> + <span class="hljs-built_in">str</span>(minute) + <span class="hljs-string">'m'</span> + <span class="hljs-built_in">str</span>(second) + <span class="hljs-string">'s'</span><br> notes.append(note)<br></code></pre></td></tr></table></figure><p>获取到对应时间点的频率及计算出来的音高，数据处理完毕</p><h3 id="前端展示"><a href="#前端展示" class="headerlink" title="前端展示"></a>前端展示</h3><p>相对复杂一些</p><p>使用plotly js进行数据展示，性能较好且考虑到跨平台使用了Flask开放对应接口使用<br>音频图展示比较容易但是动画相对复杂一些，plotly自带的动画插入帧可以实现基本的波形动画，但是无法获取每一帧的事件，没有办法进行回调处理。<br>于是曲线救国使用setInterval定时绘制标头及计算滚动rangeslider</p><figure class="highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><code class="hljs javascript"><span class="hljs-comment">//计算range范围</span><br><span class="hljs-keyword">var</span> xrange = <span class="hljs-number">20</span>; <span class="hljs-comment">//当前屏展示的时间范围</span><br><span class="hljs-keyword">var</span> startX = x/<span class="hljs-number">100</span>;<br>startX = startX>xrange/<span class="hljs-number">5</span>*<span class="hljs-number">2</span>?startX-xrange/<span class="hljs-number">5</span>*<span class="hljs-number">2</span>:<span class="hljs-number">0</span>;<br><span class="hljs-title class_">Plotly</span>.<span class="hljs-title function_">update</span>(<span class="hljs-string">"plot"</span>, {}, {<span class="hljs-attr">xaxis</span>:{<span class="hljs-attr">range</span>:[startX, startX+xrange]}});<br></code></pre></td></tr></table></figure><p>setInterval会有一些延迟，目前还没有找到好的解决方案</p><h3 id="使用地址及效果展示"><a href="#使用地址及效果展示" class="headerlink" title="使用地址及效果展示"></a>使用地址及效果展示</h3><p><strong><a href="https://taotail.pythonanywhere.com/">https://taotail.pythonanywhere.com/</a></strong><br><img src="/2023/02/07/pitch-analys/%E9%A3%9E%E5%84%BF%E4%B9%90%E5%9B%A2-%E6%9C%88%E7%89%99%E6%B9%BE.png" alt="图片"></p>]]></content>
<categories>
<category>Python</category>
<category>Flask</category>
</categories>
<tags>
<tag>Pitch</tag>
<tag>Plotly</tag>
<tag>parsermouth</tag>
<tag>tensorflow</tag>
</tags>
</entry>
<entry>
<title>HtmlGenerator（2）</title>
<link href="/2022/10/17/HtmlGenerator2/"/>
<url>/2022/10/17/HtmlGenerator2/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h3 id="对上一篇进行补充"><a href="#对上一篇进行补充" class="headerlink" title="对上一篇进行补充"></a>对上一篇进行补充</h3><p>链接<a href="/2022/05/13/HtmlGenerator/">HTML表格生成器</a></p><h4 id="新增列单元格自动合并功能"><a href="#新增列单元格自动合并功能" class="headerlink" title="新增列单元格自动合并功能"></a>新增列单元格自动合并功能</h4><p>大概思路就是统计指定列，记录内容连续相等的单元格，然后进行HTML合并操作</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 生成HTML表格</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> tableStyle 表格样式 example "<table style=\"text-align:center;\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\">"</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> columnsStyle 指定某列样式 </span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> cellStyles 指定某个单元格列样式 row<field, style></span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> mergerFields 需要合并的列</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@return</span></span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> String <span class="hljs-title function_">generateTable</span><span class="hljs-params">(String tableStyle, Map<Integer,String> columnStyles, Map<Integer, Map<String, String>> cellStyles, String... mergerColFields)</span> {<br> <br> Map<Integer, Map<String, Integer>> mergeCols = <span class="hljs-keyword">new</span> <span class="hljs-title class_">HashMap</span><>(); <span class="hljs-comment">//存储合并单元格信息</span><br> Map<String, Integer> startRowMap = <span class="hljs-keyword">new</span> <span class="hljs-title class_">HashMap</span><>();<br> Map<String, Integer> rowsCountMap = <span class="hljs-keyword">new</span> <span class="hljs-title class_">HashMap</span><>();<br> <span class="hljs-keyword">for</span>(String mergerColField:mergerColFields) {<br> rowsCountMap.put(mergerColField, <span class="hljs-number">0</span>);<br> startRowMap.put(mergerColField, <span class="hljs-number">0</span>);<br> }<br> Map<String, Object> lastValues = <span class="hljs-keyword">new</span> <span class="hljs-title class_">HashMap</span><>();<br> <span class="hljs-type">int</span> <span class="hljs-variable">row</span> <span class="hljs-operator">=</span> <span class="hljs-number">0</span>;<br> <span class="hljs-comment">//统计合并信息</span><br> <span class="hljs-keyword">for</span>(Object element : collection) {<br> <span class="hljs-keyword">for</span>(String mergerColField:mergerColFields) {<br> <span class="hljs-type">Object</span> <span class="hljs-variable">fieldValue</span> <span class="hljs-operator">=</span> getFieldValueByName(element, mergerColField);<br> <span class="hljs-keyword">if</span>(row==<span class="hljs-number">0</span>) {<br> lastValues.put(mergerColField, fieldValue);<span class="hljs-comment">//初次使用需要</span><br> }<br> <span class="hljs-type">Object</span> <span class="hljs-variable">value</span> <span class="hljs-operator">=</span> lastValues.get(mergerColField);<br> <span class="hljs-keyword">if</span>((value!=<span class="hljs-literal">null</span> && value.equals(fieldValue)) || (value==<span class="hljs-literal">null</span> && fieldValue==<span class="hljs-literal">null</span>)) {<br> rowsCountMap.put(mergerColField, rowsCountMap.get(mergerColField) + <span class="hljs-number">1</span>);<br> } <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(rowsCountMap.get(mergerColField) ><span class="hljs-number">1</span>) {<br> Map<String, Integer> fieldCols = mergeCols.get(row) == <span class="hljs-literal">null</span>?<span class="hljs-keyword">new</span> <span class="hljs-title class_">HashMap</span><>():mergeCols.get(row);<br> fieldCols.put(mergerColField, rowsCountMap.get(mergerColField));<br> mergeCols.put(startRowMap.get(mergerColField), fieldCols);<br> rowsCountMap.put(mergerColField, <span class="hljs-number">1</span>);<br> startRowMap.put(mergerColField, row);<br> } <span class="hljs-keyword">else</span> {<br> startRowMap.put(mergerColField, row);<br> }<br> lastValues.put(mergerColField, fieldValue);<br> <span class="hljs-keyword">if</span>(row == collection.size()-<span class="hljs-number">1</span> && rowsCountMap.get(mergerColField)><span class="hljs-number">1</span>) {<br> <span class="hljs-type">int</span> <span class="hljs-variable">startRow</span> <span class="hljs-operator">=</span> startRowMap.get(mergerColField);<br> Map<String, Integer> fieldCols = mergeCols.get(startRow) == <span class="hljs-literal">null</span>?<span class="hljs-keyword">new</span> <span class="hljs-title class_">HashMap</span><>():mergeCols.get(startRow);<br> fieldCols.put(mergerColField, rowsCountMap.get(mergerColField));<br> mergeCols.put(startRow, fieldCols);<br> }<br> }<br> row++;<br> }<br> <span class="hljs-type">StringBuilder</span> <span class="hljs-variable">content</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">StringBuilder</span>();<br> <span class="hljs-keyword">if</span>(tableStyle == <span class="hljs-literal">null</span>) {<br> content.append(DEFAULT_TABLE_STYLE);<br> } <span class="hljs-keyword">else</span> {<br> content.append(tableStyle);<br> }<br><br> <span class="hljs-comment">//表头创建</span><br> content.append(<span class="hljs-string">"<tr>"</span>);<br> <span class="hljs-keyword">for</span>(String key:<span class="hljs-built_in">this</span>.keySet()) {<br> content.append(<span class="hljs-string">"<td><h4>"</span>).append(get(key)).append(<span class="hljs-string">"</h4>"</span>);<br> }<br> content.append(<span class="hljs-string">"</tr>"</span>);<br> <span class="hljs-comment">//表体创建</span><br> row = <span class="hljs-number">0</span>;<br> rowsCountMap.clear();<br> <span class="hljs-keyword">for</span>(Object element : collection) {<br> <span class="hljs-keyword">if</span>(columnStyles!=<span class="hljs-literal">null</span> && columnStyles.get(row) != <span class="hljs-literal">null</span>) {<br> content.append(<span class="hljs-string">"<tr style\""</span>).append(columnStyles.get(row)).append(<span class="hljs-string">"\">"</span>);<br> } <span class="hljs-keyword">else</span> {<br> content.append(<span class="hljs-string">"<tr>"</span>);<br> }<br> Map<String, Integer> fieldCols = mergeCols.get(row);<br> rowsCountMap.forEach((k,v) -> {<br> rowsCountMap.put(k, v-<span class="hljs-number">1</span>);<br> });<br> <span class="hljs-keyword">for</span>(String key:<span class="hljs-built_in">this</span>.keySet()) {<br> <span class="hljs-keyword">if</span>(rowsCountMap.get(key)!=<span class="hljs-literal">null</span> && rowsCountMap.get(key) > <span class="hljs-number">0</span>) <span class="hljs-keyword">continue</span>;<br> content.append(<span class="hljs-string">"<td "</span>);<br> <span class="hljs-keyword">if</span>(fieldCols!=<span class="hljs-literal">null</span> && fieldCols.get(key)!=<span class="hljs-literal">null</span>) {<br> rowsCountMap.put(key, fieldCols.get(key));<br> content.append(<span class="hljs-string">"rowspan=\""</span>).append(fieldCols.get(key)).append(<span class="hljs-string">"\""</span>);<br> }<br> <span class="hljs-keyword">if</span>(cellStyles!=<span class="hljs-literal">null</span> && cellStyles.get(<span class="hljs-number">0</span>)!=<span class="hljs-literal">null</span> && cellStyles.get(<span class="hljs-number">0</span>).get(key) != <span class="hljs-literal">null</span>) {<br> content.append(<span class="hljs-string">"style=\""</span>).append(cellStyles.get(<span class="hljs-number">0</span>).get(key)).append(<span class="hljs-string">"\""</span>);<br> }<br> content.append(<span class="hljs-string">">"</span>);<br> <span class="hljs-type">Object</span> <span class="hljs-variable">value</span> <span class="hljs-operator">=</span> getFieldValueByName(element, key);<br> <span class="hljs-keyword">if</span>(value != <span class="hljs-literal">null</span>) {<br> <span class="hljs-keyword">if</span>(value <span class="hljs-keyword">instanceof</span> java.math.BigDecimal) {<br> <span class="hljs-keyword">if</span>(bigDecimalFormat == HtmlGeneratorEnum.BIGDECIMAL_PERCENTAGE_FORMAT) {<br> value = ((BigDecimal) value).multiply(BigDecimal.valueOf(<span class="hljs-number">100</span>)).setScale(<span class="hljs-number">2</span>);<br> }<br> content.append(value).append(<span class="hljs-string">"%"</span>);<br> } <span class="hljs-keyword">else</span> {<br> content.append(value);<br> }<br> }<br> content.append(<span class="hljs-string">"</td>"</span>);<br> }<br> content.append(<span class="hljs-string">"</tr>"</span>);<br> row++;<br> }<br> content.append(<span class="hljs-string">"</table>"</span>);<br><span class="hljs-comment">//String s = content.toString();</span><br> <span class="hljs-keyword">return</span> content.toString();<br>}<br></code></pre></td></tr></table></figure><h4 id="单元格横向合并思路差不多，需求暂时没有，后续可能会写"><a href="#单元格横向合并思路差不多，需求暂时没有，后续可能会写" class="headerlink" title="单元格横向合并思路差不多，需求暂时没有，后续可能会写"></a>单元格横向合并思路差不多，需求暂时没有，后续可能会写</h4>]]></content>
<categories>
<category>Java</category>
</categories>
<tags>
<tag>HtmlGenerator</tag>
</tags>
</entry>
<entry>
<title>基于OKHttp实现WebSocket客户端</title>
<link href="/2022/07/05/websocket-client-with-okhttp/"/>
<url>/2022/07/05/websocket-client-with-okhttp/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h2 id="新建WebSocketService类"><a href="#新建WebSocketService类" class="headerlink" title="新建WebSocketService类"></a>新建WebSocketService类</h2><h3 id="新建接口类为了后续回调使用"><a href="#新建接口类为了后续回调使用" class="headerlink" title="新建接口类为了后续回调使用"></a>新建接口类为了后续回调使用</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><code class="hljs java"><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * WebSocket监听事件接口</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">interface</span> <span class="hljs-title class_">IWebSocketServiceListener</span> {<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onWSClosed</span><span class="hljs-params">(WebSocket webSocket, <span class="hljs-type">int</span> code, String reason)</span>;<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onWSClosing</span><span class="hljs-params">(WebSocket webSocket, <span class="hljs-type">int</span> code, String reason)</span>;<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onWSFailure</span><span class="hljs-params">(WebSocket webSocket, Throwable t, Response response)</span>;<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onWSMessage</span><span class="hljs-params">(WebSocket webSocket, String text)</span>;<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onWSMessage</span><span class="hljs-params">(WebSocket webSocket, ByteString bytes)</span>;<br><br>}<br><br></code></pre></td></tr></table></figure><h3 id="新建内部类继承WebSocketListener以及自定义回调接口"><a href="#新建内部类继承WebSocketListener以及自定义回调接口" class="headerlink" title="新建内部类继承WebSocketListener以及自定义回调接口"></a>新建内部类继承WebSocketListener以及自定义回调接口</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">class</span> <span class="hljs-title class_">MyWebSocketListener</span> <span class="hljs-keyword">extends</span> <span class="hljs-title class_">WebSocketListener</span> {<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onOpen</span><span class="hljs-params">(WebSocket webSocket, Response response)</span> {<br> <span class="hljs-built_in">super</span>.onOpen(webSocket, response);<br> <span class="hljs-comment">//自定义心跳检测</span><br> heartBeatTimer = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Timer</span>();<br> heartBeatTimerTask = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TimerTask</span>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">run</span><span class="hljs-params">()</span> {<br> webSocket.send(<span class="hljs-string">"ping"</span>);<br> }<br> };<br> heartBeatTimer.schedule(heartBeatTimerTask, <span class="hljs-number">0</span>, <span class="hljs-number">10000</span>);<br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onClosed</span><span class="hljs-params">(WebSocket webSocket, <span class="hljs-type">int</span> code, String reason)</span> {<br> <span class="hljs-built_in">super</span>.onClosed(webSocket, code, reason);<br> webSocketServiceListener.onWSClosed(webSocket, code, reason);<br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onClosing</span><span class="hljs-params">(WebSocket webSocket, <span class="hljs-type">int</span> code, String reason)</span> {<br> <span class="hljs-built_in">super</span>.onClosing(webSocket, code, reason);<br> webSocketServiceListener.onWSClosing(webSocket, code, reason);<br> <span class="hljs-comment">//失败重试</span><br> <span class="hljs-keyword">if</span>(retryTimes<MAX_RETRY_TIMES){<br> connect();<br> retryTimes ++;<br> }<br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onFailure</span><span class="hljs-params">(WebSocket webSocket, Throwable t, Response response)</span> {<br> <span class="hljs-built_in">super</span>.onFailure(webSocket, t, response);<br> webSocketServiceListener.onWSFailure(webSocket, t, response);<br> <span class="hljs-comment">//失败重试</span><br><span class="hljs-comment">// if(retryTimes<MAX_RETRY_TIMES){</span><br><span class="hljs-comment">// connect();</span><br><span class="hljs-comment">// retryTimes ++;</span><br><span class="hljs-comment">// }</span><br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onMessage</span><span class="hljs-params">(WebSocket webSocket, String text)</span> {<br> <span class="hljs-built_in">super</span>.onMessage(webSocket, text);<br> <span class="hljs-type">JSONObject</span> <span class="hljs-variable">json</span> <span class="hljs-operator">=</span> JSONObject.parseObject(text);<br> <span class="hljs-keyword">if</span>(<span class="hljs-string">"ping"</span>.equals(json.getString(<span class="hljs-string">"type"</span>))){<br> heartBeat();<br> }<br> webSocketServiceListener.onWSMessage(webSocket, text);<br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onMessage</span><span class="hljs-params">(WebSocket webSocket, ByteString bytes)</span> {<br> <span class="hljs-built_in">super</span>.onMessage(webSocket, bytes);<br> webSocketServiceListener.onWSMessage(webSocket, bytes);<br> }<br>}<br><br></code></pre></td></tr></table></figure><h3 id="完整代码"><a href="#完整代码" class="headerlink" title="完整代码"></a>完整代码</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span class="line">116</span><br><span class="line">117</span><br><span class="line">118</span><br><span class="line">119</span><br><span class="line">120</span><br><span class="line">121</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">WebSocketService</span> {<br> <br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> OkHttpClient mClient;<br> <span class="hljs-keyword">private</span> WebSocket websocket;<br> <span class="hljs-keyword">private</span> IWebSocketServiceListener webSocketServiceListener;<br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 重试次数</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">private</span> <span class="hljs-type">int</span> <span class="hljs-variable">retryTimes</span> <span class="hljs-operator">=</span> <span class="hljs-number">0</span>;<br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 最大重试次数</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-type">int</span> <span class="hljs-variable">MAX_RETRY_TIMES</span> <span class="hljs-operator">=</span> <span class="hljs-number">5</span>;<br><br> <span class="hljs-keyword">public</span> <span class="hljs-title function_">WebSocketService</span><span class="hljs-params">(IWebSocketServiceListener webSocketServiceListener)</span>{<br> <span class="hljs-built_in">this</span>.webSocketServiceListener = webSocketServiceListener;<br> connect();<br> }<br><br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 建立websocket连接</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">connect</span><span class="hljs-params">()</span>{<br> <span class="hljs-keyword">if</span>(mClient == <span class="hljs-literal">null</span>){<br> mClient = <span class="hljs-keyword">new</span> <span class="hljs-title class_">OkHttpClient</span>.Builder()<br> .readTimeout(<span class="hljs-number">5</span>, TimeUnit.SECONDS)<span class="hljs-comment">//设置读取超时时间</span><br> .writeTimeout(<span class="hljs-number">5</span>, TimeUnit.SECONDS)<span class="hljs-comment">//设置写的超时时间</span><br> .connectTimeout(<span class="hljs-number">5</span>, TimeUnit.SECONDS)<span class="hljs-comment">//设置连接超时时间</span><br><span class="hljs-comment">// .pingInterval(10, TimeUnit.SECONDS) //OkHttp自带心跳检测，如果有自定义的需要使用heartBeatTimer进行定时发送心跳检测</span><br> .build();<br> }<br> <span class="hljs-type">String</span> <span class="hljs-variable">url</span> <span class="hljs-operator">=</span> <span class="hljs-string">"wss://..."</span>;<br> <span class="hljs-type">Request</span> <span class="hljs-variable">request</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Request</span>.Builder().get().url(url).build();<br> websocket = mClient.newWebSocket(request, <span class="hljs-keyword">new</span> <span class="hljs-title class_">MyWebSocketListener</span>());<br> }<br><br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 建立websocket连接</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">reConnect</span><span class="hljs-params">()</span>{<br> close();<br> connect();<br> }<br><br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 发送消息</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> msg</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@return</span></span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-type">boolean</span> <span class="hljs-title function_">sendMsg</span><span class="hljs-params">(String msg)</span>{<br> <span class="hljs-keyword">return</span> websocket.send(msg);<br> }<br><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">close</span><span class="hljs-params">()</span>{<br> <span class="hljs-keyword">if</span>(websocket != <span class="hljs-literal">null</span>){<br> websocket.close(<span class="hljs-number">1001</span>, <span class="hljs-string">"客户端主动关闭连接"</span>);<br> websocket = <span class="hljs-literal">null</span>;<br> }<br> }<br><br> <span class="hljs-keyword">class</span> <span class="hljs-title class_">MyWebSocketListener</span> <span class="hljs-keyword">extends</span> <span class="hljs-title class_">WebSocketListener</span> {<br> <br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onOpen</span><span class="hljs-params">(WebSocket webSocket, Response response)</span> {<br> <span class="hljs-built_in">super</span>.onOpen(webSocket, response);<br> <span class="hljs-comment">//自定义心跳检测</span><br> heartBeatTimer = <span class="hljs-keyword">new</span> <span class="hljs-title class_">Timer</span>();<br> heartBeatTimerTask = <span class="hljs-keyword">new</span> <span class="hljs-title class_">TimerTask</span>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">run</span><span class="hljs-params">()</span> {<br> webSocket.send(<span class="hljs-string">"ping"</span>);<br> }<br> };<br> heartBeatTimer.schedule(heartBeatTimerTask, <span class="hljs-number">0</span>, <span class="hljs-number">10000</span>);<br> }<br> <br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onClosed</span><span class="hljs-params">(WebSocket webSocket, <span class="hljs-type">int</span> code, String reason)</span> {<br> <span class="hljs-built_in">super</span>.onClosed(webSocket, code, reason);<br> webSocketServiceListener.onWSClosed(webSocket, code, reason);<br> }<br> <br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onClosing</span><span class="hljs-params">(WebSocket webSocket, <span class="hljs-type">int</span> code, String reason)</span> {<br> <span class="hljs-built_in">super</span>.onClosing(webSocket, code, reason);<br> webSocketServiceListener.onWSClosing(webSocket, code, reason);<br> <span class="hljs-comment">//失败重试</span><br> <span class="hljs-keyword">if</span>(retryTimes<MAX_RETRY_TIMES){<br> reConnect();<br> retryTimes ++;<br> }<br> }<br> <br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onFailure</span><span class="hljs-params">(WebSocket webSocket, Throwable t, Response response)</span> {<br> <span class="hljs-built_in">super</span>.onFailure(webSocket, t, response);<br> webSocketServiceListener.onWSFailure(webSocket, t, response);<br> <span class="hljs-comment">//失败重试</span><br> <span class="hljs-comment">// if(retryTimes<MAX_RETRY_TIMES){</span><br> <span class="hljs-comment">// reConnect();</span><br> <span class="hljs-comment">// retryTimes ++;</span><br> <span class="hljs-comment">// }</span><br> }<br> <br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onMessage</span><span class="hljs-params">(WebSocket webSocket, String text)</span> {<br> <span class="hljs-built_in">super</span>.onMessage(webSocket, text);<br> <span class="hljs-type">JSONObject</span> <span class="hljs-variable">json</span> <span class="hljs-operator">=</span> JSONObject.parseObject(text);<br> <span class="hljs-keyword">if</span>(<span class="hljs-string">"ping"</span>.equals(json.getString(<span class="hljs-string">"type"</span>))){<br> heartBeat();<br> }<br> webSocketServiceListener.onWSMessage(webSocket, text);<br> }<br> <br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onMessage</span><span class="hljs-params">(WebSocket webSocket, ByteString bytes)</span> {<br> <span class="hljs-built_in">super</span>.onMessage(webSocket, bytes);<br> webSocketServiceListener.onWSMessage(webSocket, bytes);<br> }<br> }<br>}<br></code></pre></td></tr></table></figure><h3 id="使用方法"><a href="#使用方法" class="headerlink" title="使用方法"></a>使用方法</h3><p>首先在需要使用的类中实现IWebSocketServiceListener接口<br>然后初始化webSocketService</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs java">WebSocketService = <span class="hljs-keyword">new</span> <span class="hljs-title class_">WebSocketService</span>(<span class="hljs-built_in">this</span>);<br></code></pre></td></tr></table></figure><p>然后在接口方法中实现具体的业务逻辑就可以了</p>]]></content>
<categories>
<category>Java</category>
<category>Net</category>
</categories>
<tags>
<tag>OKHttp</tag>
<tag>WebSocket</tag>
<tag>WebSocket Client</tag>
</tags>
</entry>
<entry>
<title>Java实现简易的消息队列</title>
<link href="/2022/05/26/EasyMessageQueue/"/>
<url>/2022/05/26/EasyMessageQueue/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><p>最近有个需求需要实现消息发送的频率限制，并且延后发送。使用了一个自定义的简易消息队列</p><h3 id="实现"><a href="#实现" class="headerlink" title="实现"></a>实现</h3><p>定义一个Map用来存储不同消息类型的队列，队列使用的阻塞队列ArrayBlockingQueue</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> ConcurrentHashMap<String, ArrayBlockingQueue<DingTalkRobotSendVO>> robotSendQueue = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ConcurrentHashMap</span><>();<br></code></pre></td></tr></table></figure><p>一些队列及ScheduledThreadPoolExecutor线程池参数配置</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 阻塞队列大小</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">int</span> <span class="hljs-variable">ROBOT_SEND_QUEUE_SIZE</span> <span class="hljs-operator">=</span> <span class="hljs-number">50</span>;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 队列插入移出等待时间</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">Long</span> <span class="hljs-variable">ROBOT_SEND_QUEUE_WAIT_TIME</span> <span class="hljs-operator">=</span> <span class="hljs-number">3L</span>;<br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 定时任务线程池</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> ScheduledExecutorService threadPool;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 一个周期内最多发送次数</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">int</span> <span class="hljs-variable">SEND_MAX_COUNT</span> <span class="hljs-operator">=</span> <span class="hljs-number">20</span>;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 初始化线程池</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">static</span> {<br> <span class="hljs-type">ThreadFactory</span> <span class="hljs-variable">threadFactory</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">NameTreadFactory</span>();<br> <span class="hljs-type">RejectedExecutionHandler</span> <span class="hljs-variable">handler</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">MyIgnorePolicy</span>();<br> threadPool = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ScheduledThreadPoolExecutor</span>(<span class="hljs-number">5</span>, threadFactory, handler);<br>}<br></code></pre></td></tr></table></figure><p>线程池线程命名规则</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">static</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">NameTreadFactory</span> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">ThreadFactory</span> {<br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">final</span> <span class="hljs-type">AtomicInteger</span> <span class="hljs-variable">mThreadNum</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">AtomicInteger</span>(<span class="hljs-number">1</span>);<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> Thread <span class="hljs-title function_">newThread</span><span class="hljs-params">(Runnable r)</span> {<br> <span class="hljs-type">Thread</span> <span class="hljs-variable">t</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Thread</span>(r, <span class="hljs-string">"DingTalkRobotSend-Thread-"</span> + mThreadNum.getAndIncrement());<br> LOG.info(t.getName() + <span class="hljs-string">" has been created"</span>);<br> <span class="hljs-keyword">return</span> t;<br> }<br>}<br></code></pre></td></tr></table></figure><p>线程池拒绝策略</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">MyIgnorePolicy</span> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">RejectedExecutionHandler</span> {<br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">rejectedExecution</span><span class="hljs-params">(Runnable r, ThreadPoolExecutor e)</span> {<br> doLog(r, e);<br> }<br><br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">doLog</span><span class="hljs-params">(Runnable r, ThreadPoolExecutor e)</span> {<br> LOG.info(<span class="hljs-string">"线程池请求拒绝completedTaskCount: "</span> + e.getCompletedTaskCount());<br> }<br>}<br></code></pre></td></tr></table></figure><p>核心队列消费线程定时任务</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 为每一个队列发布定时任务任务</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> queue</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">addTask</span><span class="hljs-params">(<span class="hljs-keyword">final</span> ArrayBlockingQueue<DingTalkRobotSendVO> queue)</span> {<br> <span class="hljs-comment">//等待上一个任务结束时才开始计时</span><br> threadPool.scheduleWithFixedDelay(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Runnable</span>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">run</span><span class="hljs-params">()</span> {<br> <span class="hljs-type">int</span> <span class="hljs-variable">count</span> <span class="hljs-operator">=</span> <span class="hljs-number">0</span>;<br> LOG.info(<span class="hljs-string">"Start Queue Size:"</span> + queue.size());<br> <span class="hljs-keyword">while</span>(queue.size()><span class="hljs-number">0</span> && count < SEND_MAX_COUNT) {<br> count ++;<br> <span class="hljs-type">DingTalkRobotSendVO</span> <span class="hljs-variable">robotSendVO</span> <span class="hljs-operator">=</span> <span class="hljs-literal">null</span>;<br> <span class="hljs-keyword">try</span> {<br> <span class="hljs-comment">//取出数据若无则等待加入队列元素一定时间</span><br> robotSendVO = queue.poll(ROBOT_SEND_QUEUE_WAIT_TIME, TimeUnit.SECONDS);<br> Thread.sleep(<span class="hljs-number">500</span>);<br> LOG.info(robotSendVO.toString());<br> } <span class="hljs-keyword">catch</span> (InterruptedException e) {<br> LOG.error(<span class="hljs-string">"队列取出阻塞异常{}"</span>, e);<br> }<br> }<br> LOG.info(<span class="hljs-string">"End Queue Size:"</span> + queue.size());<br> }<br> }, <span class="hljs-number">1</span>, <span class="hljs-number">60</span>, TimeUnit.SECONDS);<br>}<br></code></pre></td></tr></table></figure><p>添加任务到消息队列</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br></pre></td><td class="code"><pre><code class="hljs java">ArrayBlockingQueue<DingTalkRobotSendVO> queue;<br><span class="hljs-comment">//ConcurrentHashMap写是线程安全读是不安全的，此处加锁为了避免读取不到robotSendQueue数据而重复添加覆盖队列</span><br><span class="hljs-keyword">synchronized</span> (QueueManager.robotSendQueue) {<br> queue = QueueManager.robotSendQueue.get(sendType);<br> <span class="hljs-keyword">if</span>(queue == <span class="hljs-literal">null</span>) {<br> queue = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ArrayBlockingQueue</span><DingTalkRobotSendVO>(QueueManager.ROBOT_SEND_QUEUE_SIZE, <span class="hljs-literal">true</span>);<br> QueueManager.robotSendQueue.put(dingTalkRobotSendVO.getRobotUrl(), queue);<br> QueueManager.addTask(queue);<br> LOG.info(<span class="hljs-string">"加入任务组"</span> + dingTalkRobotSendVO.getRobotUrl());<br> }<br>}<br><span class="hljs-keyword">try</span> {<br> <span class="hljs-comment">//添加任务到消息队列，若消息队列已满等待一定时间</span><br> <span class="hljs-type">boolean</span> <span class="hljs-variable">result</span> <span class="hljs-operator">=</span> queue.offer(dingTalkRobotSendVO, QueueManager.ROBOT_SEND_QUEUE_WAIT_TIME, TimeUnit.SECONDS);<br> <span class="hljs-keyword">if</span>(result) {<br> LOG.info(<span class="hljs-string">"加入队列成功"</span>);<br> } <span class="hljs-keyword">else</span> {<br> LOG.info(<span class="hljs-string">"加入队列失败"</span>);<br> }<br>} <span class="hljs-keyword">catch</span> (InterruptedException e) {<br> LOG.error(<span class="hljs-string">"加入队列阻塞异常{}"</span>, e);<br>}<br></code></pre></td></tr></table></figure><h3 id="附上完整代码"><a href="#附上完整代码" class="headerlink" title="附上完整代码"></a>附上完整代码</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 队列管理工具</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@author</span> XX</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">QueueManager</span> {<br><br><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-type">Logger</span> <span class="hljs-variable">LOG</span> <span class="hljs-operator">=</span> LoggerFactory.getLogger(QueueManager.class);<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 所有队列存储</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> ConcurrentHashMap<String, ArrayBlockingQueue<DingTalkRobotSendVO>> robotSendQueue = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ConcurrentHashMap</span><>();<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 阻塞队列大小</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">int</span> <span class="hljs-variable">ROBOT_SEND_QUEUE_SIZE</span> <span class="hljs-operator">=</span> <span class="hljs-number">50</span>;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 队列插入移出等待时间</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">Long</span> <span class="hljs-variable">ROBOT_SEND_QUEUE_WAIT_TIME</span> <span class="hljs-operator">=</span> <span class="hljs-number">3L</span>;<br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 定时任务线程池</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> ScheduledExecutorService threadPool;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 一周期内最多发送次数</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-type">int</span> <span class="hljs-variable">SEND_MAX_COUNT</span> <span class="hljs-operator">=</span> <span class="hljs-number">20</span>;<br><br><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-type">IDingTalkService</span> <span class="hljs-variable">dingTalkService</span> <span class="hljs-operator">=</span> (IDingTalkService) ServerContext<br>.getApplicationContext().getBean(<span class="hljs-string">"dingTalkService"</span>);<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 初始化线程池</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">static</span> {<br> <span class="hljs-type">ThreadFactory</span> <span class="hljs-variable">threadFactory</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">NameTreadFactory</span>();<br> <span class="hljs-type">RejectedExecutionHandler</span> <span class="hljs-variable">handler</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">MyIgnorePolicy</span>();<br> threadPool = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ScheduledThreadPoolExecutor</span>(<span class="hljs-number">5</span>, threadFactory, handler);<br>}<br> <br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 为每一个队列发布定时任务任务</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> queue</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">addTask</span><span class="hljs-params">(<span class="hljs-keyword">final</span> ArrayBlockingQueue<DingTalkRobotSendVO> queue)</span> {<br> <span class="hljs-comment">//等待上一个任务结束时才开始计时</span><br> threadPool.scheduleWithFixedDelay(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Runnable</span>() {<br><span class="hljs-meta">@Override</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">run</span><span class="hljs-params">()</span> {<br><span class="hljs-type">int</span> <span class="hljs-variable">count</span> <span class="hljs-operator">=</span> <span class="hljs-number">0</span>;<br>LOG.info(<span class="hljs-string">"Start Queue Size:"</span> + queue.size());<br><span class="hljs-keyword">while</span>(queue.size()><span class="hljs-number">0</span> && count < SEND_MAX_COUNT) {<br>count ++;<br><span class="hljs-type">DingTalkRobotSendVO</span> <span class="hljs-variable">robotSendVO</span> <span class="hljs-operator">=</span> <span class="hljs-literal">null</span>;<br><span class="hljs-keyword">try</span> {<br>robotSendVO = queue.poll(ROBOT_SEND_QUEUE_WAIT_TIME, TimeUnit.SECONDS);<br>Thread.sleep(<span class="hljs-number">500</span>);<br>LOG.info(robotSendVO.toString());<br>} <span class="hljs-keyword">catch</span> (InterruptedException e) {<br>LOG.error(<span class="hljs-string">"队列取出阻塞异常{}"</span>, e);<br>}<br>}<br>LOG.info(<span class="hljs-string">"End Queue Size:"</span> + queue.size());<br>}<br>}, <span class="hljs-number">1</span>, <span class="hljs-number">60</span>, TimeUnit.SECONDS);<br> }<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 线程命名规则</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@author</span> XX</span><br><span class="hljs-comment"> *</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">static</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">NameTreadFactory</span> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">ThreadFactory</span> {<br><br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">final</span> <span class="hljs-type">AtomicInteger</span> <span class="hljs-variable">mThreadNum</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">AtomicInteger</span>(<span class="hljs-number">1</span>);<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> Thread <span class="hljs-title function_">newThread</span><span class="hljs-params">(Runnable r)</span> {<br> <span class="hljs-type">Thread</span> <span class="hljs-variable">t</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Thread</span>(r, <span class="hljs-string">"DingTalkRobotSend-Thread-"</span> + mThreadNum.getAndIncrement());<br> LOG.info(t.getName() + <span class="hljs-string">" has been created"</span>);<br> <span class="hljs-keyword">return</span> t;<br> }<br> }<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 拒绝策略</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@author</span> XX</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">MyIgnorePolicy</span> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">RejectedExecutionHandler</span> {<br><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">rejectedExecution</span><span class="hljs-params">(Runnable r, ThreadPoolExecutor e)</span> {<br> doLog(r, e);<br> }<br><br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">doLog</span><span class="hljs-params">(Runnable r, ThreadPoolExecutor e)</span> {<br> LOG.info(<span class="hljs-string">"线程池请求拒绝completedTaskCount: "</span> + e.getCompletedTaskCount());<br> }<br> }<br>}<br></code></pre></td></tr></table></figure>]]></content>
<categories>
<category>Java</category>
<category>多线程</category>
</categories>
<tags>
<tag>java</tag>
<tag>Queue</tag>
<tag>MessageQueue</tag>
<tag>ConcurrentHashMap</tag>
</tags>
</entry>
<entry>
<title>记录一下Spring框架中的频率次数拦截限制</title>
<link href="/2022/05/24/RequestLimit/"/>
<url>/2022/05/24/RequestLimit/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h2 id="定义注解"><a href="#定义注解" class="headerlink" title="定义注解"></a>定义注解</h2><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-meta">@Documented</span><br><span class="hljs-meta">@Target(ElementType.METHOD)</span> <span class="hljs-comment">// 说明该注解只能放在方法上面</span><br><span class="hljs-meta">@Retention(RetentionPolicy.RUNTIME)</span><br><span class="hljs-keyword">public</span> <span class="hljs-meta">@interface</span> RequestLimit {<br> <span class="hljs-type">long</span> <span class="hljs-title function_">time</span><span class="hljs-params">()</span> <span class="hljs-keyword">default</span> <span class="hljs-number">60000</span>; <span class="hljs-comment">// 限制时间 单位：毫秒</span><br> <span class="hljs-type">int</span> <span class="hljs-title function_">count</span><span class="hljs-params">()</span> <span class="hljs-keyword">default</span> <span class="hljs-number">20</span>; <span class="hljs-comment">// 允许请求的次数</span><br>}<br></code></pre></td></tr></table></figure><h2 id="配置拦截器"><a href="#配置拦截器" class="headerlink" title="配置拦截器"></a>配置拦截器</h2><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-meta">@Component</span><br><span class="hljs-keyword">class</span> <span class="hljs-title class_">ReqLimitInterceptor</span> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">HandlerInterceptor</span> {<br><br><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> ConcurrentHashMap<String, ExpiringMap<Object, Object>> book = <span class="hljs-keyword">new</span> <span class="hljs-title class_">ConcurrentHashMap</span><String, ExpiringMap<Object, Object>>();<br><br><span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-type">boolean</span> <span class="hljs-title function_">preHandle</span><span class="hljs-params">(HttpServletRequest request, HttpServletResponse response, Object handler)</span> {<br><span class="hljs-type">String</span> <span class="hljs-variable">url</span> <span class="hljs-operator">=</span> request.getParameter(<span class="hljs-string">"robotUrl"</span>)==<span class="hljs-literal">null</span>?request.getRequestURI():request.getParameter(<span class="hljs-string">"robotUrl"</span>);<br><span class="hljs-type">HandlerMethod</span> <span class="hljs-variable">handlerMethod</span> <span class="hljs-operator">=</span> (HandlerMethod) handler;<br> <span class="hljs-comment">// 获取接口方法的注解</span><br> <span class="hljs-type">RequestLimit</span> <span class="hljs-variable">annotation</span> <span class="hljs-operator">=</span> handlerMethod.getMethodAnnotation(RequestLimit.class);<br> <span class="hljs-keyword">if</span> (annotation == <span class="hljs-literal">null</span>) {<br> <span class="hljs-keyword">return</span> <span class="hljs-literal">true</span>;<br> }<br><span class="hljs-comment">// 获取Map对象， 如果没有则返回默认值使用book.getOrDefault</span><br><span class="hljs-comment">// 第一个参数是key， 第二个参数是默认值</span><br>ExpiringMap<Object, Object> expiringMap = book.get(request.getRequestURI()) == <span class="hljs-literal">null</span>?<br>ExpiringMap.builder().variableExpiration().build():book.get(request.getRequestURI());<br><br><span class="hljs-type">Integer</span> <span class="hljs-variable">count</span> <span class="hljs-operator">=</span> (Integer) expiringMap.get(url);<br><span class="hljs-keyword">if</span>(count == <span class="hljs-literal">null</span>) {<br>count = <span class="hljs-number">0</span>;<br>}<br><br><span class="hljs-keyword">if</span> (count >= annotation.count()) { <span class="hljs-comment">// 超过次数，不执行目标方法</span><br><span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">TechnologyException</span>(<span class="hljs-string">"ERR-0300"</span>, <span class="hljs-keyword">new</span> <span class="hljs-title class_">Object</span>[] {annotation.time(), annotation.count()});<br>} <span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span> (count == <span class="hljs-number">0</span>){ <span class="hljs-comment">// 第一次请求时，设置有效时间</span><br>expiringMap.put(url, count + <span class="hljs-number">1</span>, ExpirationPolicy.CREATED, annotation.time(), TimeUnit.MILLISECONDS);<br>} <span class="hljs-keyword">else</span> { <span class="hljs-comment">// 未超过次数， 记录加一</span><br>expiringMap.put(url, count + <span class="hljs-number">1</span>);<br>}<br>book.put(request.getRequestURI(), expiringMap);<br><span class="hljs-keyword">return</span> <span class="hljs-literal">true</span>;<br> }<br><br><span class="hljs-meta">@Override</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">afterCompletion</span><span class="hljs-params">(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3)</span><br><span class="hljs-keyword">throws</span> Exception {<br><br>}<br><br><span class="hljs-meta">@Override</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">postHandle</span><span class="hljs-params">(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3)</span><br><span class="hljs-keyword">throws</span> Exception {<br><br>}<br>}<br></code></pre></td></tr></table></figure><p>这里使用了一个三方net.jodah.expiringmap.ExpiringMap用于实现Map数据过期自动删除,也可以使用redis缓存等实现。<br>同时除了拦截器也可以使用AOP实现。<br>需要配合异常拦截器返回异常结果</p><h2 id="使用方法"><a href="#使用方法" class="headerlink" title="使用方法"></a>使用方法</h2><p>Controller方法加上注解即可</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-meta">@RequestLimit(time = 60000, count = 20)</span><br></code></pre></td></tr></table></figure><h3 id="SpringMVC需要在配置文件中添加配置"><a href="#SpringMVC需要在配置文件中添加配置" class="headerlink" title="SpringMVC需要在配置文件中添加配置"></a>SpringMVC需要在配置文件中添加配置</h3><figure class="highlight xml"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><code class="hljs xml"><span class="hljs-comment"><!-- 拦截器 --></span><br><span class="hljs-tag"><<span class="hljs-name">mvc:interceptors</span>></span><br> <span class="hljs-comment"><!--拦截所有资源--></span><br> <span class="hljs-tag"><<span class="hljs-name">bean</span> <span class="hljs-attr">class</span>=<span class="hljs-string">"*.ReqLimitInterceptor"</span>></span><span class="hljs-tag"></<span class="hljs-name">bean</span>></span><br><span class="hljs-tag"></<span class="hljs-name">mvc:interceptors</span>></span><br></code></pre></td></tr></table></figure>]]></content>
<categories>
<category>Java</category>
<category>Spring</category>
</categories>
<tags>
<tag>Spring</tag>
<tag>SpringMVC</tag>
<tag>SpringBoot</tag>
<tag>Interceptor</tag>
<tag>拦截器</tag>
<tag>频率限制</tag>
</tags>
</entry>
<entry>
<title>HtmlGenerator-HTML表格等生成器</title>
<link href="/2022/05/13/HtmlGenerator/"/>
<url>/2022/05/13/HtmlGenerator/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h3 id="使用方法"><a href="#使用方法" class="headerlink" title="使用方法"></a>使用方法</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-type">HTMLGenerator</span> <span class="hljs-variable">htmlGenerator</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">HTMLGenerator</span>(traceHeaderVOs);<br>htmlGenerator.put(<span class="hljs-string">"XXX"</span>, <span class="hljs-string">"表头名"</span>); <span class="hljs-comment">//XXX属性名</span><br>...<br>htmlGenerator.generateTable();<br></code></pre></td></tr></table></figure><h3 id="源码"><a href="#源码" class="headerlink" title="源码"></a>源码</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span 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class="line">146</span><br><span class="line">147</span><br><span class="line">148</span><br><span class="line">149</span><br><span class="line">150</span><br><span class="line">151</span><br><span class="line">152</span><br><span class="line">153</span><br><span class="line">154</span><br><span class="line">155</span><br><span class="line">156</span><br><span class="line">157</span><br><span class="line">158</span><br><span class="line">159</span><br></pre></td><td class="code"><pre><code class="hljs java"><br><span class="hljs-keyword">import</span> java.beans.PropertyDescriptor;<br><span class="hljs-keyword">import</span> java.lang.reflect.Method;<br><span class="hljs-keyword">import</span> java.util.Collection;<br><span class="hljs-keyword">import</span> java.util.LinkedHashMap;<br><span class="hljs-keyword">import</span> java.util.Map;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@Description</span> HTML生成器</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@author</span> XX</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@Param</span> </span><br><span class="hljs-comment"> * <span class="hljs-doctag">@return</span> </span><br><span class="hljs-comment">**/</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">HTMLGenerator</span> <span class="hljs-keyword">extends</span> <span class="hljs-title class_">LinkedHashMap</span><String, String> {<br><br><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> <span class="hljs-type">long</span> <span class="hljs-variable">serialVersionUID</span> <span class="hljs-operator">=</span> -<span class="hljs-number">2844894776581720941L</span>;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 生成数据集合</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">private</span> Collection<?> collection;<br><br><span class="hljs-keyword">public</span> <span class="hljs-title function_">HTMLGenerator</span><span class="hljs-params">(Collection<?> collection)</span> {<br><span class="hljs-built_in">super</span>();<br><span class="hljs-built_in">this</span>.collection = collection;<br>}<br><br><span class="hljs-comment">//private static HTMLGenerator htmlGenerator;</span><br><span class="hljs-comment">//</span><br><span class="hljs-comment">//public static synchronized HTMLGenerator getInstance(Collection<?> collection) {</span><br><span class="hljs-comment">//if(htmlGenerator == null) {</span><br><span class="hljs-comment">//htmlGenerator = new HTMLGenerator();</span><br><span class="hljs-comment">//}</span><br><span class="hljs-comment">//htmlGenerator.setCollection(collection);</span><br><span class="hljs-comment">//return htmlGenerator;</span><br><span class="hljs-comment">//}</span><br><br><span class="hljs-keyword">public</span> Collection<?> getCollection() {<br><span class="hljs-keyword">return</span> collection;<br>}<br><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">setCollection</span><span class="hljs-params">(Collection<?> collection)</span> {<br><span class="hljs-built_in">this</span>.collection = collection;<br>}<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 默认表格样式</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> <span class="hljs-type">String</span> <span class="hljs-variable">DEFAULT_TABLE_STYLE</span> <span class="hljs-operator">=</span> <span class="hljs-string">"<style>.pure-table{text-align:center;border-collapse:collapse;border-spacing:0;empty-cells:show;border:1px solid #cbcbcb}.pure-table caption{color:#000;font:italic 85%/1 arial,sans-serif;padding:1em 0;text-align:center}.pure-table td,.pure-table th{border-left:1px solid #cbcbcb;border-width:0 0 0 1px;font-size:inherit;margin:0;overflow:visible;padding:.5em 1em}.pure-table thead{background-color:#e0e0e0;color:#000;text-align:left;vertical-align:bottom}.pure-table td{background-color:transparent}</style>"</span>;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 附加样式</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-type">String</span> <span class="hljs-variable">style</span> <span class="hljs-operator">=</span> <span class="hljs-string">""</span>;<br><br><span class="hljs-keyword">public</span> String <span class="hljs-title function_">generateTable</span><span class="hljs-params">()</span> {<br><span class="hljs-keyword">return</span> generateTable(<span class="hljs-literal">null</span>, <span class="hljs-literal">null</span>, <span class="hljs-literal">null</span>);<br>}<br><br><span class="hljs-keyword">public</span> String <span class="hljs-title function_">generateTable</span><span class="hljs-params">(String tableStyle)</span> {<br><span class="hljs-keyword">return</span> generateTable(tableStyle, <span class="hljs-literal">null</span>, <span class="hljs-literal">null</span>);<br>}<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 生成HTML表格</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> tableStyle 表格样式 example "<table style=\"text-align:center;\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\">"</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> columnsStyles 指定某列样式 </span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> cellStyles 指定某个单元格列样式</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@return</span></span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> String <span class="hljs-title function_">generateTable</span><span class="hljs-params">(String tableStyle, Map<Integer,String> columnsStyles, Map<Integer,RowColumnPair> cellStyles)</span> {<br><span class="hljs-comment">//TODO columnsStyle</span><br><span class="hljs-comment">//TODO cellStyles</span><br><span class="hljs-type">StringBuilder</span> <span class="hljs-variable">content</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">StringBuilder</span>();<br>content.append(DEFAULT_TABLE_STYLE);<br><span class="hljs-keyword">if</span>(tableStyle == <span class="hljs-literal">null</span>) {<br>content.append(<span class="hljs-string">"<table class=\"pure-table\">"</span>);<br>} <span class="hljs-keyword">else</span> {<br>content.append(tableStyle);<br>}<br><span class="hljs-comment">//表头创建</span><br>content.append(<span class="hljs-string">"<tr>"</span>);<br><span class="hljs-keyword">for</span>(String key:<span class="hljs-built_in">this</span>.keySet()) {<br>content.append(<span class="hljs-string">"<td><h4>"</span>).append(get(key)).append(<span class="hljs-string">"</h4>"</span>);<br>}<br>content.append(<span class="hljs-string">"</tr>"</span>);<br><span class="hljs-comment">//表体创建</span><br><span class="hljs-type">int</span> <span class="hljs-variable">row</span> <span class="hljs-operator">=</span> <span class="hljs-number">0</span>;<br><span class="hljs-keyword">for</span>(Object element : collection) {<br>content.append(<span class="hljs-string">"<tr>"</span>);<br><span class="hljs-keyword">for</span>(String key:<span class="hljs-built_in">this</span>.keySet()) {<br>content.append(<span class="hljs-string">"<td>"</span>).append(getFieldValueByName(element, key)).append(<span class="hljs-string">"</td>"</span>);<br>}<br>content.append(<span class="hljs-string">"</tr>"</span>);<br>row++;<br>}<br>content.append(<span class="hljs-string">"</table>"</span>);<br><span class="hljs-keyword">return</span> content.toString();<br>}<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 通过反射获取参数对应的属性值</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> o 对象</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> fieldName 字段名</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@return</span></span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">private</span> String <span class="hljs-title function_">getFieldValueByName</span><span class="hljs-params">(Object o, String fieldName)</span> {<br> <span class="hljs-keyword">try</span> {<br> <span class="hljs-type">PropertyDescriptor</span> <span class="hljs-variable">pd</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">PropertyDescriptor</span>(fieldName, o.getClass());<br> <span class="hljs-type">Method</span> <span class="hljs-variable">getMethod</span> <span class="hljs-operator">=</span> pd.getReadMethod();<br> <span class="hljs-type">Object</span> <span class="hljs-variable">obj</span> <span class="hljs-operator">=</span> getMethod.invoke(o);<br> <span class="hljs-type">return</span> <span class="hljs-variable">null</span> <span class="hljs-operator">=</span>= obj ? <span class="hljs-literal">null</span> : obj.toString(); <br> } <span class="hljs-keyword">catch</span> (Exception e) {<br> <span class="hljs-keyword">return</span> <span class="hljs-literal">null</span>;<br>}<br><br> }<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 用于定位表格单元格</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@author</span> XX</span><br><span class="hljs-comment"> *</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">RowColumnPair</span> {<br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 属性名</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">private</span> String columnField;<br><br><span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 样式</span><br><span class="hljs-comment"> */</span><br><span class="hljs-keyword">private</span> String style;<br><br><span class="hljs-keyword">public</span> <span class="hljs-title function_">RowColumnPair</span><span class="hljs-params">(String columnField, String style)</span> {<br><span class="hljs-built_in">super</span>();<br><span class="hljs-built_in">this</span>.columnField = columnField;<br><span class="hljs-built_in">this</span>.style = style;<br>}<br><br><span class="hljs-keyword">public</span> String <span class="hljs-title function_">getColumnField</span><span class="hljs-params">()</span> {<br><span class="hljs-keyword">return</span> columnField;<br>}<br><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">setColumnField</span><span class="hljs-params">(String columnField)</span> {<br><span class="hljs-built_in">this</span>.columnField = columnField;<br>}<br><br><span class="hljs-keyword">public</span> String <span class="hljs-title function_">getStyle</span><span class="hljs-params">()</span> {<br><span class="hljs-keyword">return</span> style;<br>}<br><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">setStyle</span><span class="hljs-params">(String style)</span> {<br><span class="hljs-built_in">this</span>.style = style;<br>}<br><br>}<br><br>}<br></code></pre></td></tr></table></figure>]]></content>
<categories>
<category>Java</category>
</categories>
<tags>
<tag>HtmlGenerator</tag>
</tags>
</entry>
<entry>
<title>RxJava、Retrofit结合使用进行网络请求</title>
<link href="/2022/05/11/RxJavaWithRetrofit/"/>
<url>/2022/05/11/RxJavaWithRetrofit/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h3 id="引言"><a href="#引言" class="headerlink" title="引言"></a>引言</h3><p>上两篇文章分别提到了retrofit以及RxJava的使用以及好处，这篇文章开始介绍它们的结合使用</p><h3 id="首先引入相关的包"><a href="#首先引入相关的包" class="headerlink" title="首先引入相关的包"></a>首先引入相关的包</h3><pre><code>implementation 'io.reactivex.rxjava3:rxandroid:3.0.0' //rxjavaimplementation 'com.squareup.retrofit2:retrofit:2.9.0' //retrofitimplementation 'com.squareup.retrofit2:retrofit-converters:2.9.0' //rxjava2对应适配包（二选1）implementation 'com.squareup.retrofit2:adapter-rxjava3:2.9.0' //rxjava3对应适配包（二选1）implementation group: 'com.squareup.okhttp3', name: 'okhttp', version: '4.9.1'</code></pre><h3 id="创建retrofit接口"><a href="#创建retrofit接口" class="headerlink" title="创建retrofit接口"></a>创建retrofit接口</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">import</span> io.reactivex.rxjava3.core.Flowable;<br><span class="hljs-keyword">import</span> io.reactivex.rxjava3.core.Observable;<br><span class="hljs-keyword">import</span> okhttp3.MultipartBody;<br><span class="hljs-keyword">import</span> okhttp3.ResponseBody;<br><span class="hljs-keyword">import</span> retrofit2.Response;<br><span class="hljs-keyword">import</span> retrofit2.http.Body;<br><span class="hljs-keyword">import</span> retrofit2.http.Field;<br><span class="hljs-keyword">import</span> retrofit2.http.FormUrlEncoded;<br><span class="hljs-keyword">import</span> retrofit2.http.GET;<br><span class="hljs-keyword">import</span> retrofit2.http.Header;<br><span class="hljs-keyword">import</span> retrofit2.http.Headers;<br><span class="hljs-keyword">import</span> retrofit2.http.Multipart;<br><span class="hljs-keyword">import</span> retrofit2.http.POST;<br><span class="hljs-keyword">import</span> retrofit2.http.Part;<br><span class="hljs-keyword">import</span> retrofit2.http.Query;<br><span class="hljs-keyword">import</span> retrofit2.http.Url;<br><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">interface</span> <span class="hljs-title class_">IRetrofitApi</span> {<br> <span class="hljs-meta">@FormUrlEncoded</span><br> <span class="hljs-meta">@Headers({"Domain-Name: api"})</span><br> <span class="hljs-meta">@POST("payment/alipay")</span><br> Observable<Response<String>> <span class="hljs-title function_">alipay</span><span class="hljs-params">(<span class="hljs-meta">@Field("user_id")</span> String userId, <span class="hljs-meta">@Field("money")</span> <span class="hljs-type">int</span> money)</span>;<br>}<br></code></pre></td></tr></table></figure><p>其中RxJava的Observable替换了retrofit的Call类型，Response<String>泛型String可替换成返回的数据类型，我这里因为要解密返回密文所以使用String接收</String></p><h3 id="创建retrofit接口调用类"><a href="#创建retrofit接口调用类" class="headerlink" title="创建retrofit接口调用类"></a>创建retrofit接口调用类</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">RetrofitSource</span> {<br> <span class="hljs-keyword">private</span> IRetrofitApi api;<br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-type">RetrofitSource</span> <span class="hljs-variable">retrofitSource</span> <span class="hljs-operator">=</span> <span class="hljs-literal">null</span>;<br><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">synchronized</span> RetrofitSource <span class="hljs-title function_">instance</span><span class="hljs-params">()</span>{<br> <span class="hljs-keyword">if</span>(retrofitSource == <span class="hljs-literal">null</span>) {<br> retrofitSource = <span class="hljs-keyword">new</span> <span class="hljs-title class_">RetrofitSource</span>();<br> }<br> <span class="hljs-keyword">return</span> retrofitSource;<br> }<br><br> <span class="hljs-keyword">public</span> <span class="hljs-title function_">RetrofitSource</span><span class="hljs-params">()</span> {<br> <span class="hljs-type">OkHttpClient</span> <span class="hljs-variable">mClient</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">OkHttpClient</span>.Builder()<br> .addInterceptor(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Interceptor</span>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> okhttp3.Response <span class="hljs-title function_">intercept</span><span class="hljs-params">(Chain chain)</span> <span class="hljs-keyword">throws</span> IOException {<br> <span class="hljs-keyword">try</span> {<br> Request.<span class="hljs-type">Builder</span> <span class="hljs-variable">builder</span> <span class="hljs-operator">=</span> chain.request().newBuilder();<br> builder.addHeader(<span class="hljs-string">"Accept-Charset"</span>, <span class="hljs-string">"UTF-8"</span>) <span class="hljs-comment">//统一添加请求头</span><br> .addHeader(<span class="hljs-string">"Accept"</span>, <span class="hljs-string">" application/json"</span>);<br><br> <span class="hljs-type">Request</span> <span class="hljs-variable">request</span> <span class="hljs-operator">=</span> builder.build();<br> <span class="hljs-keyword">return</span> chain.proceed(request);<br> } <span class="hljs-keyword">catch</span> (Exception e) {<br> e.printStackTrace();<br> }<br> <span class="hljs-keyword">return</span> <span class="hljs-literal">null</span>;<br> }<br> }).build();<br> <span class="hljs-type">Retrofit</span> <span class="hljs-variable">retrofit</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br> .baseUrl(AppConfig.host + API_VERSION)<br><span class="hljs-comment">// .addConverterFactory(GsonConverterFactory.create())</span><br> .addCallAdapterFactory(RxJava3CallAdapterFactory.create()) <span class="hljs-comment">//用于上面提到的的Retrofit</span><br> .addConverterFactory(StringConverterFactory.create())<br> .client(mClient)<br> .build();<br> api = retrofit.create(IRetrofitApi.class);<br> }<br><br>}<br></code></pre></td></tr></table></figure><h2 id="初始化解析"><a href="#初始化解析" class="headerlink" title="初始化解析"></a>初始化解析</h2><h3 id="初始化OkHttpClient"><a href="#初始化OkHttpClient" class="headerlink" title="初始化OkHttpClient"></a>初始化OkHttpClient</h3><p>主要是添加拦截器来修改请求的配置</p><h3 id="初始化retrofit及retrofitApi"><a href="#初始化retrofit及retrofitApi" class="headerlink" title="初始化retrofit及retrofitApi"></a>初始化retrofit及retrofitApi</h3><pre><code>.addCallAdapterFactory(RxJava3CallAdapterFactory.create()) </code></pre><p>用于上面提到的的Retrofit的Call转换成RxJava的Observable。</p><pre><code>.addConverterFactory(StringConverterFactory.create())</code></pre><p>用于将请求结果的解析成对应类型数据。</p><p>解析Gson可以使用</p><pre><code>.addConverterFactory(GsonConverterFactory.create())</code></pre><p>不要忘记单独添加依赖</p><pre><code>compile 'com.squareup.retrofit2:converter-gson:2.9.0'</code></pre><h2 id="请求方法"><a href="#请求方法" class="headerlink" title="请求方法"></a>请求方法</h2><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> Observable<Response<String>> <span class="hljs-title function_">alipay</span><span class="hljs-params">(String userId, <span class="hljs-type">int</span> money)</span> {<br> <span class="hljs-keyword">return</span> <span class="hljs-built_in">this</span>.api.alipay(userId, money);<br>}<br></code></pre></td></tr></table></figure><p>初始化时Retrofit已经用动态代理生成Observable网络请求对象，所以这里调用接口方法能直接进行网络接口请求</p><h1 id="使用RxJava调用接口"><a href="#使用RxJava调用接口" class="headerlink" title="使用RxJava调用接口"></a>使用RxJava调用接口</h1><p>RxJava调用可以简化代码使代码更清晰，以及能切换线程的方法，在android中实现结果返回时操作UI线程。省去了Android handler或者AsyncTask的复杂创建，抽象了HTTP请求接口，使代码结构更清楚</p><h2 id="自定义观察者基类"><a href="#自定义观察者基类" class="headerlink" title="自定义观察者基类"></a>自定义观察者基类</h2><p>创建一个观察者抽象基类实现Observer接口中onSubscribe onNext onComplete方法，泛型是返回的数据类型，新增了自己的两个回调接口方法</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">abstract</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">BaseObserver</span><T> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">Observer</span><Response<String>> {<br><br> <span class="hljs-keyword">private</span> T result; <span class="hljs-comment">//返回结果</span><br><br> <span class="hljs-keyword">public</span> T <span class="hljs-title function_">getResult</span><span class="hljs-params">()</span> {<br> <span class="hljs-keyword">return</span> result;<br> }<br><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">setResult</span><span class="hljs-params">(T result)</span> {<br> <span class="hljs-built_in">this</span>.result = result;<br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onSubscribe</span><span class="hljs-params">(<span class="hljs-meta">@NonNull</span> Disposable d)</span> {<br> <br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onNext</span><span class="hljs-params">(<span class="hljs-meta">@NonNull</span> Response<String> stringResponse)</span> {<br> ...<br> <span class="hljs-comment">//这边进行数据的封装处理</span><br> <span class="hljs-comment">//成功回调onSuccess(result)接口</span><br> <span class="hljs-comment">//失败回调onFail(msg)接口</span><br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onComplete</span><span class="hljs-params">()</span> {<br><br> }<br><br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 成功回调</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> result</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">abstract</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onSuccess</span><span class="hljs-params">(T result)</span>;<br><br> <span class="hljs-comment">/**</span><br><span class="hljs-comment"> * 错误回调</span><br><span class="hljs-comment"> * <span class="hljs-doctag">@param</span> msg</span><br><span class="hljs-comment"> */</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">abstract</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onFail</span><span class="hljs-params">(String msg)</span>;<br><br>}<br></code></pre></td></tr></table></figure><h2 id="RetrofitSource调用接口并传入Observer对象处理"><a href="#RetrofitSource调用接口并传入Observer对象处理" class="headerlink" title="RetrofitSource调用接口并传入Observer对象处理"></a>RetrofitSource调用接口并传入Observer对象处理</h2><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br></pre></td><td class="code"><pre><code class="hljs java">RetrofitSource.instance().alipay(uid)<br> .subscribeOn(Schedulers.io())<br> .observeOn(AndroidSchedulers.mainThread()) <span class="hljs-comment">//切换andoirdUI线程操作</span><br> .subscribe(<span class="hljs-keyword">new</span> <span class="hljs-title class_">BaseObserver</span><BaseResponse<ResultBean>>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onError</span><span class="hljs-params">(<span class="hljs-meta">@io</span>.reactivex.rxjava3.annotations.NonNull Throwable e)</span> {<br> <span class="hljs-comment">//请求失败回调</span><br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onSuccess</span><span class="hljs-params">(BaseResponse<ResultBean> result)</span> {<br> <span class="hljs-comment">//获取结果并进行UI操作</span><br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onFail</span><span class="hljs-params">(String msg)</span> {<br> <span class="hljs-comment">//返回结果处理失败回调</span><br> }<br> });<br> }<br></code></pre></td></tr></table></figure><p>到此已经能使用此方法进行网络请求操作了，结构清晰，代码简洁。</p><h1 id="总结"><a href="#总结" class="headerlink" title="总结"></a>总结</h1><p>对于网络访问的抽象与优化，实际上是个非常难的课题，在Retrofit之前，大家努力的方向基本上都是Volley/OkHttp这种围绕底层网络访问的工作。<br>因为越底层的东西越容易抽象，越上升到接近业务层，就越容易在纷扰的业务层中迷失。<br>Retrofit能精准地抓到Call网络工作对象这个关键点，并能通过一系列精巧的设计实现对这种类型“飘忽不定”的对象的自动化定制生产，着实令人赞叹。</p>]]></content>
<categories>
<category>Java</category>
</categories>
<tags>
<tag>RxAndroid</tag>
<tag>Java</tag>
<tag>原创</tag>
<tag>Android</tag>
</tags>
</entry>
<entry>
<title>RxJava的使用</title>
<link href="/2022/05/11/RxJava/"/>
<url>/2022/05/11/RxJava/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><h3 id="RxJava介绍"><a href="#RxJava介绍" class="headerlink" title="RxJava介绍"></a>RxJava介绍</h3><p>首先要说明的一点，RxAndroid和RxJava是差不多的东西，只不过RxAndroid 针对Android平台做了一点调整。那么RxJava是什么？在其github上是这样讲的：一个在 Java VM 上使用可观测的序列来组成异步的、基于事件的程序的库。这么讲可能还有点绕口，简单的讲实际上最重要的就是异步两字，RxJava可以简单的实现异步操作，并且不管逻辑多么复杂，它始终能够保持简洁性。<br>通常在Android中，非UI线程是不能更新UI界面的，而一些耗时的操作我们又不能放在UI线程，否则会导致界面卡顿。这种情况下，我们就需要切换线程来实现，即Handler和AsyncTask来实现，但是这两种都有个缺陷，代码非常多，非常杂，可读性非常差。所以，RxJava出现了，它能够两行代码就实现线程切换，非常的简单，使用起来就会让人感觉很爽，再也不用为异步操作写如此繁重的代码了。</p><h3 id="RxJava基本用法"><a href="#RxJava基本用法" class="headerlink" title="RxJava基本用法"></a>RxJava基本用法</h3><p>RxJava最核心的两个东西是Observables（被观察者，事件源）和Observer/Subscriber（观察者），还有将他们联系在一起的操作subscribe（订阅）。当被观察者发生变化时观察者能即使做出相应，就好像我们的按钮事件一样：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java">button.setOnClickListener(<span class="hljs-keyword">new</span> <span class="hljs-title class_">View</span>.OnClickListener() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onClick</span><span class="hljs-params">(View v)</span> {<br><br> }<br> });<br></code></pre></td></tr></table></figure><p>在这里button就是被观察者，OnClickListener就是观察者，setOnClickListener这个方法就相当于订阅操作，当button被按下时，OnClickListener监听到变化，调用OnClick做出反应，RxJava实现的就是类似这样的一个过程。注意这里的观察者有两种Observer，Subscriber，这两个其实是差不多的，Subscriber是对Observer的一种扩展，内部增加了OnStart方法，在事件未发送之前订阅，用于做一些准备工作，并且还有unsubscribe()用于取消订阅。<br>让我们来看一下ObServer的内部实现：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">interface</span> <span class="hljs-title class_">Observer</span><T> {<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onCompleted</span><span class="hljs-params">()</span>;<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onError</span><span class="hljs-params">(Throwable e)</span>;<br><br> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onNext</span><span class="hljs-params">(T t)</span>;<br><br>}<br></code></pre></td></tr></table></figure><p>可以看到ObServer本身是一个接口，内部有onNext(T t)方法：观测到所检测的被观察者有变化时做出相应反应。onCompleted()方法：RxJava 规定，当不会再有新的 onNext() 发出时，需要触发 onCompleted() 方法作为标志。onCompleted()：事件队列发生异常，要调用的方法。我们在定义一个观察者的时候，需要实现这些方法，来完成事件队列。<br>观察者有了，那么被观察者Observables怎么创建呢，RxJava提供了一系列操作符供我们调用，其中就有很多创建型操作符，举个例子,创建一个Observables，发出hello world字符串给观察者：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><code class="hljs java">Observable<String> myObservable = Observable.create( <br> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Observable</span>.OnSubscribe<String>() { <br> <span class="hljs-meta">@Override</span> <br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">call</span><span class="hljs-params">(Subscriber<? <span class="hljs-built_in">super</span> String> sub)</span> { <br> sub.onNext(<span class="hljs-string">"Hello, world!"</span>); <br> sub.onCompleted(); <br> } <br> } );<br></code></pre></td></tr></table></figure><p>既然有了Observables，那我们就可以根据这个Observables创建一个观察者了，如下：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><code class="hljs java">Observer<String> TestObserver=<span class="hljs-keyword">new</span> <span class="hljs-title class_">Observer</span><String>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onCompleted</span><span class="hljs-params">()</span> {<br><br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onError</span><span class="hljs-params">(Throwable e)</span> {<br><br> }<br><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onNext</span><span class="hljs-params">(String s)</span> {<br> Log.i(TAG,s);<br> }<br> }<br></code></pre></td></tr></table></figure><p>这样我们就可以愉快的订阅了：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs java">myObservable.subscribe(TestObserver);<br></code></pre></td></tr></table></figure><p>这样，一个简单的RxJava订阅流程就完成了。这里可能很多人就有疑问了，关键的异步呢，体现在哪了？其实这个例子可能不是很明显，因为被观察者并不是一个耗时线程，不能很直观的体现异步。如果myObservable这是一个异步任务，比如网络请求，那么我们订阅之后，TestObserver会一直监听myObservable是否有返回，如果有，那么就做出响应，本质是一样的。</p><h3 id="RxJava的操作符"><a href="#RxJava的操作符" class="headerlink" title="RxJava的操作符"></a>RxJava的操作符</h3><p>RxJava一个强大的地方在于它的异步，另外一个强大的地方就在于它提供了强大的操作符支持。这里说明一下几个常用的操作符：</p><ul><li> ceate操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><code class="hljs java">Observable<String> myObservable = Observable.create( <br> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Observable</span>.OnSubscribe<String>() { <br> <span class="hljs-meta">@Override</span> <br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">call</span><span class="hljs-params">(Subscriber<? <span class="hljs-built_in">super</span> String> sub)</span> { <br> sub.onNext(<span class="hljs-string">"Hello, world!"</span>); <br> sub.onCompleted(); <br> } <br> } );<br></code></pre></td></tr></table></figure><p>ceate操作符创建一个被观察者，在call方法里持有一个观察者Subscriber参数，当这个Observable被订阅时，执行观察者相应的方法。</p><ul><li> just操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs java">Observable<String> myObservable = Observable.just(<span class="hljs-string">"Hello, world!"</span>);<br></code></pre></td></tr></table></figure><p>上面的代码可以用这一句话，代替。just操作符的功能就是将一个对象转化为Observable。</p><ul><li> from操作符</li></ul><p> <code class=" language-csharp">Observable<String> myObservable = Observable.from("Hello"," world!");</String></code></p><figure class="highlight golo"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><code class="hljs golo"><br>既然有了将单一对象转化为<span class="hljs-keyword">Observable</span>的操作符，那么必须要有将多个对象转化为<span class="hljs-keyword">Observable</span>的操作符，那就是from，from接收一个对象数组，然后逐一发射给观察者。<br><br>现在，用一个例子来说明其他操作符，比如我们有这样一个方法，根据学生姓名关键字查询学生列表，返回一个<span class="hljs-keyword">Observable</span>。<br><br>```java<br><span class="hljs-keyword">Observable</span><List<Student>> query(String name);<br></code></pre></td></tr></table></figure><p>然后我们的需求是一个一个的输出学生姓名，实现如下：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).subscribe(list -> {<br><span class="hljs-keyword">for</span>(Student student:list){<br> Log.i(TAG,student.getName());<br>});<br></code></pre></td></tr></table></figure><ul><li> flatMap操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .subscribe(student ->Log.i(TAG,student.getName());<br>);<br></code></pre></td></tr></table></figure><p>上面的例子用flatMap操作符，就可以变得很简洁，flatMap操作符的功能是接收一个接收一个Observable的输出作为输入，同时输出另外一个Observable，通常是接收一个list，然后逐一发送list的元素。比如这边的Student数组，变成了逐一发送student的Observable。</p><ul><li> Map操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .Map(student-><span class="hljs-keyword">return</span> student.getGrade())<br> .subscribe(grade->Log.i(TAG,grade+<span class="hljs-string">""</span>);<br>);<br></code></pre></td></tr></table></figure><p>现在我们只想输出每个学生的成绩，我们就需要Map操作符，它的功能是接收一种类型的Observable，转化为另外一种Observable，比如这边的Student类型转化为了Int型的Observable。</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .Map(student-><span class="hljs-keyword">return</span> student.getGrade())<br> .subscribe(grade->Log.i(TAG,grade+<span class="hljs-string">""</span>);<br>);<br></code></pre></td></tr></table></figure><ul><li> filter操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .Map(student-><span class="hljs-keyword">return</span> student.getGrade())<br> .filter(grade->grade><span class="hljs-number">80</span>)<br> .subscribe(grade->Log.i(TAG,grade+<span class="hljs-string">""</span>);<br>);<br></code></pre></td></tr></table></figure><p>顾名思义filter操作符就是过滤用的，相当于加个判断条件，比如这边的就是加上分数大于80的条件.</p><ul><li> take操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .Map(student-><span class="hljs-keyword">return</span> student.getGrade())<br> .filter(grade->grade><span class="hljs-number">80</span>)<br> .take(<span class="hljs-number">5</span>)<br> .subscribe(grade->Log.i(TAG,grade+<span class="hljs-string">""</span>);<br>);<br></code></pre></td></tr></table></figure><p>take操作符的功能是限定个数，比如这边的功能就是限定我最多需要5个成绩。</p><ul><li> doOnNext操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .Map(student-><span class="hljs-keyword">return</span> student.getGrade())<br> .filter(grade->grade><span class="hljs-number">80</span>)<br> .take(<span class="hljs-number">5</span>)<br> .doOnNext(grade->save(grade))<br> .subscribe(grade->Log.i(TAG,grade+<span class="hljs-string">""</span>);<br>);<br></code></pre></td></tr></table></figure><p>doOnNext()允许我们在每次输出一个元素之前做一些额外的事情，比如这里的我们用来保存成绩。</p><ul><li> subscribeOn/observeOn操作符</li></ul><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><code class="hljs java">query(<span class="hljs-string">"王"</span>).flatMap(list -> Observable.from(list)) <br> .Map(student-><span class="hljs-keyword">return</span> student.getGrade())<br> .filter(grade->grade><span class="hljs-number">80</span>)<br> .take(<span class="hljs-number">5</span>)<br> .doOnNext(grade->save(grade))<br> .subscribeOn(Schedulers.io())<br> .observeOn(AndroidSchedulers.mainThread())<br> .subscribe(grade->Log.i(TAG,grade+<span class="hljs-string">""</span>);<br>);<br></code></pre></td></tr></table></figure><p>这两个操作符一般都是成对出现的，他们的功能就是切换线程。subscribeOn是指定被观察者的线程，observeOn是指定观察者的线程。比如这个例子中前面的订阅的工作在IO线程做，后面的打印功能在主线程做。</p><ul><li>小结<br> 怎么样，看起来我好像做了很多事情，又有判断数据，又有保存数据，又有选取数据，关键还有线程切换，然而，我实际上就写了那么一点代码，看起来是不是酷！这就是RxJava的魅力所在。</li></ul><h3 id="RxAndroid"><a href="#RxAndroid" class="headerlink" title="RxAndroid"></a>RxAndroid</h3><p>一开始说了，RxAndroid其实跟RxJava是差不多的，但是总归还是有一点变化的。比如Android上会有生命周期的问题，可能会导致内存泄漏：Observable持有Context导致的内存泄露。在这个问题上，我们的解决方法是这样的：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">private</span> Subscription mTestSubscription= Subscriptions.empty();<br><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">test</span><span class="hljs-params">()</span>{<br>mTestSubscription=myObservable.subscribe(TestObserver);<br>}<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onDestroy</span><span class="hljs-params">()</span> {<br> <span class="hljs-built_in">super</span>.onDestroy();<br> <span class="hljs-keyword">if</span> (mTestSubscription != <span class="hljs-literal">null</span> && !mTestSubscription.isUnsubscribed()) {<br> mTestSubscription.unsubscribe();<br> }<br><br> }<br></code></pre></td></tr></table></figure><p>就是在订阅的时候，用一个Subscription来保存它，然后在退出这个Activity的时候取消订阅。<br>另外还有一些专门为Android设计的RxView,比如以下防抖动的View：</p><p><code>java RxView.clicks(btn_click) .throttleFirst(3, TimeUnit.SECONDS) .subscribe();</code></p><p>参考：<a href="https://www.jianshu.com/p/d9fca152017b">https://www.jianshu.com/p/d9fca152017b</a></p>]]></content>
<categories>
<category>Java</category>
<category>RxJava</category>
</categories>
<tags>
<tag>RxJava</tag>
<tag>RxAndroid</tag>
<tag>Observer</tag>
<tag>Subscriber</tag>
</tags>
</entry>
<entry>
<title>retrofit的使用</title>
<link href="/2022/05/10/retrofit/"/>
<url>/2022/05/10/retrofit/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><p>Retrofit是squareup公司的开源力作，和同属squareup公司开源的OkHttp，一个负责网络调度，一个负责网络执行，为Android开发者提供了即方便又高效的网络访问框架。</p><p>不过，对于Retrofit这样设计精妙、代码简洁、使用方便的优秀开源项目，不能仅知道如何扩展和使用，或者仅研究它采用的技术或模式，“技”当然重要，但不能忽视了背后的“道”。</p><p>对于Retrofit，我们还应该看到的，是她在优化App架构方面的努力，以及她在提升开发效率方面的借鉴和启示。</p><p>本文试图通过一个具体场景，先总结Retrofit在架构中起到的作用，再分析其实现原理，最后探讨Retrofit给我们带来的启示。</p><p>我们先通过一个简单的应用场景来回顾Retrofit的使用过程。</p><h1 id="基本场景"><a href="#基本场景" class="headerlink" title="基本场景"></a>基本场景</h1><p>通常来说，使用Retrofit要经过这样几个步骤</p><ol><li><p>引用<br> 在gradle文件中引用retrofit</p><p> compile ‘com.squareup.retrofit2:retrofit:2.3.0’<br> compile ‘com.squareup.retrofit2:retrofit-converters:2.3.0’<br> compile ‘com.squareup.retrofit2:retrofit-adapters:2.3.0’</p></li></ol><p>如果需要使用更多扩展功能，比如gson转换，rxjava适配等，可以视自己需要继续添加引用</p><pre><code>compile 'com.squareup.retrofit2:converter-gson:2.3.0'compile 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'</code></pre><figure class="highlight less"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><code class="hljs less"><br>如果现有的扩展包不能满足需要，还可以自己扩展<span class="hljs-selector-tag">converter</span>，<span class="hljs-selector-tag">adapter</span>等。<br><br><span class="hljs-number">1</span>. 定义接口<br> <span class="hljs-selector-tag">Retrofit</span>要求定义一个网络请求的接口，接口函数里要定义<span class="hljs-selector-tag">url</span>路径、请求参数、返回类型。<br><br>```<span class="hljs-selector-tag">java</span><br><span class="hljs-selector-tag">public</span> <span class="hljs-selector-tag">interface</span> <span class="hljs-selector-tag">INetApiService</span> {<br> <span class="hljs-variable">@GET</span>(<span class="hljs-string">"/demobiz/api.php"</span>)<br> Call<BizEntity> getBizInfo(<span class="hljs-variable">@Query</span>(<span class="hljs-string">"id"</span>) String id);<br>}<br></code></pre></td></tr></table></figure><p>在这个接口定义中，用注解@GET(“/demobiz/api.php”)声明了url路径，用注解@Query(“id”) 声明了请求参数。<br>最重要的是，用Call<BizEntity>声明了返回值是一个Retrofit的Call对象，并且声明了这个对象处理的数据类型为BizEntity，BizEntity是我们自定义的数据模型。</BizEntity></p><ol><li>依次获得<strong>Retrofit对象、接口实例对象、网络工作对象</strong><br> 首先，需要新建一个retrofit对象。<br> 然后，根据上一步的接口，实现一个retrofit加工过的接口对象。<br> 最后，调用接口函数，得到一个可以执行网络访问的网络工作对象。</li></ol><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//新建一个Retrofit对象</span><br>Retrofit retrofit=<span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br>.baseUrl(Config.DOMAIN)<span class="hljs-comment">//要访问的网络地址域名，如http://www.zhihu.com</span><br>.addConverterFactory(GsonConverterFactory.create())<br>.build();<br>...<br><br><span class="hljs-comment">//用retrofit加工出对应的接口实例对象</span><br>INetApiService netApiService= retrofit.create(INetApiService.class);<br><span class="hljs-comment">//可以继续加工出其他接口实例对象</span><br>IOtherService otherService= retrofit.create(IOtherService.class);<br>···<br><br><span class="hljs-comment">//调用接口函数，获得网络工作对象</span><br>Call<BizEntity> callWorker= netApiService.getBizInfo(<span class="hljs-string">"id001"</span>);<br></code></pre></td></tr></table></figure><p>这个复杂的过程下来，最终得到的callWorker对象，才可以执行网络访问。</p><ol><li>访问网络数据<br> 用上一步获取的worker对象，执行网络请求</li></ol><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java">callWorker.enqueue(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Callback</span><BizEntity>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onResponse</span><span class="hljs-params">(Call<BizEntity> call, Response<BizEntity> response)</span> {...}<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title function_">onFailure</span><span class="hljs-params">(Call<BizEntity> call, Throwable t)</span> {...}<br> });<br></code></pre></td></tr></table></figure><p>在回调函数里，取得我们需要的BizEntity数据对象。<br>网络访问结束。</p><h1 id="角色与作用"><a href="#角色与作用" class="headerlink" title="角色与作用"></a>角色与作用</h1><p>我们从上面的应用场景可以看出，Retrofit并不做网络请求，只是生成一个能做网络请求的对象。<br>Retrofit的作用是<strong>按照接口去定制Call网络工作对象</strong></p><p>什么意思？就是说：<br><strong>Retrofit不直接做网络请求<br>Retrofit不直接做网络请求<br>Retrofit不直接做网络请求</strong><br>重要的事情说三遍。</p><p>网络请求的目标虽然是数据，但是我们需要为这个数据写大量的配套代码，发起请求的对象Call，接收数据的对象CallBack，做数据转换的对象Converter，以及检查和处理异常的对象等。<br>这对于一个项目的开发、扩展和维护来说，都是成本和风险。</p><p>而Retrofit做的事情，就是为开发者节省这部分的工作量，Retrofit一方面从底层统一用OkHttp去做网络处理；另一方面在外层灵活提供能直接融入业务逻辑的Call网络访问对象。</p><p>具体来说，Retrofit只负责生产对象，生产能做网络请求的工作对象，他有点像一个工厂，只提供产品，工厂本身不处理网络请求，产品才能处理网络请求。<br>Retrofit在网络请求中的作用大概可以这样理解：</p><p><img src="/2022/05/10/retrofit/35dfaaa7.png"></p><p> Retrofit的作用</p><p>我们看到，从一开始，Retrofit要提供的就是个Call工作对象。<br>换句话说，对于给Retrofit提供的那个接口</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">interface</span> <span class="hljs-title class_">INetApiService</span> {<br> <span class="hljs-meta">@GET("/demobiz/api.php")</span><br> Call<BizEntity> <span class="hljs-title function_">getBizInfo</span><span class="hljs-params">(<span class="hljs-meta">@Query("id")</span> String id)</span>;<br>}<br></code></pre></td></tr></table></figure><p>这个接口并不是传统意义上的网络请求接口，这个接口不是用来获取数据的接口，而是用来生产对象的接口，<strong>这个接口相当于一个工厂，接口中每个函数的返回值不是网络数据，而是一个能进行网络请求的工作对象，我们要先调用函数获得工作对象，再用这个工作对象去请求网络数据。</strong></p><p>所以Retrofit的实用价值意义在于，他能根据你的接口定义，灵活地生成对应的网络工作对象，然后你再择机去调用这个对象访问网络。<br>理解了这一点，我们才能去扩展Retrofit，并理解Retrofit的设计思想。</p><h1 id="功能扩展"><a href="#功能扩展" class="headerlink" title="功能扩展"></a>功能扩展</h1><p>我们先来看Retrofit能扩展哪些功能，然后再去理解Retrofit的工作原理。<br>Retrofit主要可以扩展三个地方：</p><ol><li>OkHttpClient<br> Retrofit使用OkHttpClient来实现网络请求，这个OkHttpClient虽然不能替换为其他的网络执行框架比如Volley，但是Retrofit允许我们使用自己扩展OkHttpClient，一般最常扩展的就是Interceptor拦截器了</li></ol><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-type">OkHttpClient</span> <span class="hljs-variable">mClient</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">OkHttpClient</span>.Builder()<br> .addInterceptor(<span class="hljs-keyword">new</span> <span class="hljs-title class_">Interceptor</span>() {<br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> Response <span class="hljs-title function_">intercept</span><span class="hljs-params">(Chain chain)</span> <span class="hljs-keyword">throws</span> IOException {<br> <span class="hljs-keyword">try</span> {<br> Request.<span class="hljs-type">Builder</span> <span class="hljs-variable">builder</span> <span class="hljs-operator">=</span> chain.request().newBuilder();<br> builder.addHeader(<span class="hljs-string">"Accept-Charset"</span>, <span class="hljs-string">"UTF-8"</span>);<br> builder.addHeader(<span class="hljs-string">"Accept"</span>, <span class="hljs-string">" application/json"</span>);<br> builder.addHeader(<span class="hljs-string">"Content-type"</span>, <span class="hljs-string">"application/json"</span>);<br> <span class="hljs-type">Request</span> <span class="hljs-variable">request</span> <span class="hljs-operator">=</span> builder.build();<br> <span class="hljs-keyword">return</span> chain.proceed(request);<br> } <span class="hljs-keyword">catch</span> (Exception e) {<br> e.printStackTrace();<br> }<br> <span class="hljs-keyword">return</span> <span class="hljs-literal">null</span>;<br> }<br> }).build();<br><br><span class="hljs-type">Retrofit</span> <span class="hljs-variable">retrofit</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br> .baseUrl(Config.DOMAIN)<br> .addConverterFactory(GsonConverterFactory.create())<br> .client(mClient)<br> .build();<br></code></pre></td></tr></table></figure><ol><li> addConverterFactory</li></ol><p>扩展的是对返回的数据类型的自动转换，把一种数据对象转换为另一种数据对象。<br>在上述场景中，GsonConverterFactory可以把Http访问得到的json字符串转换为Java数据对象BizEntity，这个BizEntity是在INetApiService接口中要求的的。<br>这种转换我们自己也经常做，很好理解。<br>如果现有的扩展包不能满足需要，可以继承Retrofit的接口。retrofit2.Converter<F,T>，自己实现Converter和ConverterFactory。<br>在创建Retrofit对象时，可以插入我们自定义的ConverterFactory。</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//retrofit对象</span><br>Retrofit retrofit=<span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br>.baseUrl(Config.DOMAIN)<br>.addConverterFactory(GsonConverterFactory.create())<br>.addConverterFactory(YourConverterFactory.create())<span class="hljs-comment">//添加自定义Converter</span><br>.build();<br></code></pre></td></tr></table></figure><ol><li> addCallAdapterFactory</li></ol><p>扩展的是对网络工作对象callWorker的自动转换，把Retrofit中执行网络请求的Call对象，转换为接口中定义的Call对象。<br>这个转换不太好理解，我们可以对照下图来理解：</p><p><img src="/2022/05/10/retrofit/d496aeae.png"></p><p> callAdapter转换Call对象</p><p>Retrofit本身用一个OkHttpCall的类负责处理网络请求，而我们在接口中定义需要定义很多种Call，例如Call<BizEntity>，或者Flowable<BizEntity>等，接口里的Call和Retrofit里的OkHttpCall并不一致，所以我们需要用一个CallAdapter去做一个适配转换。<br>（Retrofit底层虽然使用了OkHttpClient去处理网络请求，但她并没有使用okhttp3.call这个Call接口，而是自己又建了一个retrofit2.Call接口，OkHttpCall继承的是retrofit2.Call，与okhttp3.call只是引用关系。<br>这样的设计符合依赖倒置原则，可以尽可能的与OkHttpClient解耦。）</BizEntity></BizEntity></p><p>这其实是Retrofit非常核心，也非常好用的一个设计，如果我们在接口中要求的函数返回值是个RxJava的Flowable对象</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">interface</span> <span class="hljs-title class_">INetApiService</span> {<br> <span class="hljs-meta">@GET("/demobiz/api.php")</span><br> Flowable<BizEntity> <span class="hljs-title function_">getBizInfo</span><span class="hljs-params">(<span class="hljs-meta">@Query("id")</span> String id)</span>;<br>}<br></code></pre></td></tr></table></figure><p>那么我们只需要为Retrofit添加对应的扩展</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//retrofit对象</span><br>Retrofit retrofit=<span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br>.baseUrl(Config.DOMAIN)<br>.addConverterFactory(GsonConverterFactory.create())<br>.addCallAdapterFactory(RxJava2CallAdapterFactory.create())<br>.build();<br></code></pre></td></tr></table></figure><p>就能得到Flowable类型的callWorker对象</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//用retrofit加工出对应的接口实例对象</span><br>INetApiService netApiService= retrofit.create(INetApiService.class);<br>···<br><span class="hljs-comment">//调用接口函数，获得网络工作对象</span><br>Flowable<BizEntity> callWorker= netApiService.getBizInfo(<span class="hljs-string">"id001"</span>);<br></code></pre></td></tr></table></figure><p>在这里，callAdapter做的事情就是把retrofit2.Call对象适配转换为Flowable<T>对象。<br>同样，如果现有的扩展包不能满足需要，可以继承Retrofit的接口retrofit2.CallAdapter<R,T>，自己实现CallAdapter和CallAdapterFactory。</T></p><h1 id="Retrofit实现原理"><a href="#Retrofit实现原理" class="headerlink" title="Retrofit实现原理"></a>Retrofit实现原理</h1><p>Retrofit固然设计精妙，代码简洁，使用方便，但相应的，我们要理解Retrofit的实现原理也不太容易，这么精妙的设计是极佳的研究素材，我们不能仅仅停留在知道怎么使用，怎么扩展的阶段，那实在是对这个优秀开源项目的浪费。<br>其实，Retrofit使用的，就是动态代理，方法注解、建造者和适配器等成熟的技术或模式，但是由于她的设计紧凑，而且动态代理屏蔽了很多过程上的细节，所以比较难以理解。</p><h1 id="Retrofit实现原理——从动态代理开始"><a href="#Retrofit实现原理——从动态代理开始" class="headerlink" title="Retrofit实现原理——从动态代理开始"></a>Retrofit实现原理——从动态代理开始</h1><p>从前面的使用场景可知，retrofit会生成一个接口实例。</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//用retrofit加工出对应的接口实例对象</span><br>INetApiService netApiService= retrofit.create(INetApiService.class);<br></code></pre></td></tr></table></figure><p>到Retrofit源码里看create函数，是一个动态代理。</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <T> T <span class="hljs-title function_">create</span><span class="hljs-params">(<span class="hljs-keyword">final</span> Class<T> service)</span> {<br> ...<br> <span class="hljs-keyword">return</span> (T) Proxy.newProxyInstance(service.getClassLoader(), <span class="hljs-keyword">new</span> <span class="hljs-title class_">Class</span><?>[] { service },<br> <span class="hljs-keyword">new</span> <span class="hljs-title class_">InvocationHandler</span>() {<br> ...<br> ServiceMethod<Object, Object> serviceMethod =<br> (ServiceMethod<Object, Object>) loadServiceMethod(method);<br> OkHttpCall<Object> okHttpCall = <span class="hljs-keyword">new</span> <span class="hljs-title class_">OkHttpCall</span><>(serviceMethod, args);<br> <span class="hljs-keyword">return</span> serviceMethod.callAdapter.adapt(okHttpCall);<br> }<br> });<br>}<br></code></pre></td></tr></table></figure><p>要理解动态代理，最好要看到动态生成的代理类。</p><p>由于动态代理是在运行时动态生成的代理类，用常规的反编译方法无法查看，一般要使用Java提供的sun.misc.ProxyGenerator.generateProxyClass(String proxyName,class[] interfaces)函数生成代理类，函数会返回byte[]字节码，然后对字节码反编译得到Java代码。<br>有一个小问题是，AndroidStudio并不提供sun.misc这个包，我们需要用IntelliJ或者Eclipse建立一个Java工程，在Java环境里调用这个函数。</p><p>拿到的代理类，大概是这样的：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> <span class="hljs-keyword">final</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">INetApiService</span> <span class="hljs-keyword">extends</span> <span class="hljs-title class_">Proxy</span> <span class="hljs-keyword">implements</span> <span class="hljs-title class_">INetApiService</span> {<br> ...<span class="hljs-comment">//一些Object自带方法</span><br> <span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> Method m3;<span class="hljs-comment">//接口定义的方法</span><br> <span class="hljs-keyword">static</span> {<br> <span class="hljs-keyword">try</span> {<br> <span class="hljs-comment">//Object自带方法的初始化</span><br> m0,m1,m2 = ...<br> <span class="hljs-comment">//接口中定义的方法</span><br> m3 = Class.forName(<span class="hljs-string">"com.demo.net$INetApiService"</span>)<span class="hljs-comment">//反射接口类</span><br> .getMethod(<span class="hljs-string">"getBizInfo"</span>,<span class="hljs-comment">//反射函数</span><br> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Class</span>[] { Class.forName(<span class="hljs-string">"java.lang.String"</span>) });<span class="hljs-comment">//反射参数</span><br> <span class="hljs-comment">//接口中定义的其他方法</span><br> ...<br> } <br> ...<br> }<br><span class="hljs-comment">//返回接口实例对象</span><br><span class="hljs-keyword">public</span> <span class="hljs-title function_">INetApiService</span> <span class="hljs-params">(InvocationHandler invocationHandler)</span>{<br> <span class="hljs-built_in">super</span>(invocationHandler);<br>}<br><span class="hljs-comment">//</span><br><span class="hljs-keyword">public</span> <span class="hljs-keyword">final</span> Call <span class="hljs-title function_">getBizInfo</span><span class="hljs-params">(String str)</span>{<br> ...<br> <span class="hljs-keyword">try</span>{<span class="hljs-comment">//用Handler去调用</span><br> <span class="hljs-keyword">return</span> (Call)<span class="hljs-built_in">this</span>.h.invoke(<span class="hljs-built_in">this</span>, m3, <span class="hljs-keyword">new</span> <span class="hljs-title class_">Object</span>[]{str});<br> }<br>}<br><br>}<br></code></pre></td></tr></table></figure><p>我们可以看到，代理类生成的是一个INetApiService接口的实例对象，该对象的getBizInfo函数返回的是接口中定义的Call网络工作对象，这也体现了Retrofit的核心价值，生成接口定义的Call网络工作对象。</p><p>那么，这个Call网络工作对象是如何生成的呢，上面动态代理生成的代码是这样的：</p><pre><code>return (Call)this.h.invoke(this, m3, new Object[]{str});</code></pre><p>也就是说，这个Call网络工作对象是在InvocationHandler中实现的，也就是在Retrofit.create函数中，由InvocationHandler实现的。</p><p>这样我们就明白了，<strong>Retrofit使用动态代理，其实是为了开发者在写代码时方便调用，而真正负责生产Call网络工作对象的，还是Retrofit.create函数中定义的这个InvocationHandler</strong>，这个InvocationHandler的代码我们再贴一遍：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">new</span> <span class="hljs-title class_">InvocationHandler</span>() {<br> ...<br> ServiceMethod<Object, Object> serviceMethod =<br> (ServiceMethod<Object, Object>) loadServiceMethod(method);<br> OkHttpCall<Object> okHttpCall = <span class="hljs-keyword">new</span> <span class="hljs-title class_">OkHttpCall</span><>(serviceMethod, args);<br> <span class="hljs-keyword">return</span> serviceMethod.callAdapter.adapt(okHttpCall);<br>}<br></code></pre></td></tr></table></figure><p>ServiceMethod能让我们准确解析到INetApiService中定义的函数，为最后的适配转换提供转换目标，详细分析我们后面再说，先看适配转换的过程。</p><p>我们看到，Retrofit内部默认使用OkHttpCall对象去处理网络请求，但是返回的网络工作对象是经过适配器转换的，转换成接口定义的那种Call网络工作对象。</p><p>这个适配转换，就是Retrofit能按照接口去定制Call网络工作对象的秘密。</p><h1 id="Retrofit实现原理——适配转换Call对象"><a href="#Retrofit实现原理——适配转换Call对象" class="headerlink" title="Retrofit实现原理——适配转换Call对象"></a>Retrofit实现原理——适配转换Call对象</h1><p>我们在初始化Retrofit对象时，好像不添加CallAdapterFactory也能实现适配转换。</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//retrofit对象</span><br>Retrofit retrofit=<span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br>.baseUrl(Config.DOMAIN)<br>.addConverterFactory(GsonConverterFactory.create())<br><span class="hljs-comment">//可以不添加CallAdapterFactory</span><br>.build();<br></code></pre></td></tr></table></figure><p>这是怎么回事呢，我们知道Retrofit使用了建造者模式，建造者模式的特定就是实现了建造和使用的分离，所以建造者模式的建造函数里，一般会有很复杂的对象创建和初始化过程，所以我们要看一下Retrofit的build函数。</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> Retrofit <span class="hljs-title function_">build</span><span class="hljs-params">()</span> {<br> ...<br> okhttp3.Call.<span class="hljs-type">Factory</span> <span class="hljs-variable">callFactory</span> <span class="hljs-operator">=</span> <span class="hljs-built_in">this</span>.callFactory;<br> <span class="hljs-keyword">if</span> (callFactory == <span class="hljs-literal">null</span>) {<br> callFactory = <span class="hljs-keyword">new</span> <span class="hljs-title class_">OkHttpClient</span>();<span class="hljs-comment">//使用OkHttpClient处理网络请求</span><br> }<br> ...<br> <span class="hljs-comment">//根据当前运行平台，设置默认的callAdapterFactory</span><br> adapterFactories.add(platform.defaultCallAdapterFactory(callbackExecutor));<br> ...<br> <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>(callFactory, baseUrl, converterFactories, adapterFactories,<br> callbackExecutor, validateEagerly);<br> }<br></code></pre></td></tr></table></figure><p>这段代码里，我们看到Retrofit使用OkHttpClient处理网络请求，并且会添加默认的callAdapterFactory，这个platform是一个简单工厂，能根据当前系统平台去生成对应的callAdapterFactory</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> Platform <span class="hljs-title function_">findPlatform</span><span class="hljs-params">()</span> {<br> <span class="hljs-keyword">try</span> {<br> Class.forName(<span class="hljs-string">"android.os.Build"</span>);<br> <span class="hljs-keyword">if</span> (Build.VERSION.SDK_INT != <span class="hljs-number">0</span>) {<br> <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Android</span>();<span class="hljs-comment">//根据当前系统平台返回相应的对象</span><br> }<br> ...<br> }<br> ...<br> <span class="hljs-keyword">static</span> <span class="hljs-keyword">class</span> <span class="hljs-title class_">Android</span> <span class="hljs-keyword">extends</span> <span class="hljs-title class_">Platform</span> {<br> ...<br> <span class="hljs-meta">@Override</span> CallAdapter.Factory <span class="hljs-title function_">defaultCallAdapterFactory</span><span class="hljs-params">(<span class="hljs-meta">@Nullable</span> Executor callbackExecutor)</span> {<br> <span class="hljs-keyword">if</span> (callbackExecutor == <span class="hljs-literal">null</span>) <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">AssertionError</span>();<br> <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">ExecutorCallAdapterFactory</span>(callbackExecutor);<br> }<br> ...<br> }<br></code></pre></td></tr></table></figure><p>这个Platform是Retrofit在Builder的构造函数里初始化的。</p><p>所以，在Retrofit.build()函数中，我们为Retrofit默认添加的callAdapterFactory，是在Platform中为Android系统设定的ExecutorCallAdapterFactory。<br>我们看ExecutorCallAdapterFactory的代码，这是一个工厂类，可以返回CallAdapter对象：</p><p> <code class=" language-tsx">@Override<br> public CallAdapter<?, ?> get(Type returnType, Annotation[] annotations, Retrofit retrofit) {<br> ...<br> return new CallAdapter<Object, call<?>>() {<br> ...<br> // 转换后 转换前，也就是OkHttpCall<br> @Override public Call<Object> adapt(Call<Object> call) {<br> return new ExecutorCallbackCall<>(callbackExecutor, call);<br> }<br> };<br> }</Object></Object></Object,></code></p><figure class="highlight swift"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br></pre></td><td class="code"><pre><code class="hljs swift"><br>在adapt函数中，适配器会把<span class="hljs-type">Retrofit中用来访问网络的OkHttpCall，转换为一个ExecutorCallbackCall</span>(继承了<span class="hljs-type">INetApiService接口里要求返回的网络工作对象retrofit2</span>.<span class="hljs-type">Call</span>)，<br>这个例子里面，由于<span class="hljs-type">OkHttpCall和ExecutorCallbackCall都实现了retrofit2</span>.<span class="hljs-type">Call接口，结果出现了从Call</span><<span class="hljs-type">Object</span>>转换为<span class="hljs-type">Call</span><<span class="hljs-type">Object</span>>的情况，这可能不容易理解，我们换个<span class="hljs-type">RxJava2CallAdapterFactory来看看</span><br><br>```java<br><span class="hljs-comment">//RxJava2CallAdapterFactory中</span><br> <span class="hljs-meta">@Override</span><br> <span class="hljs-keyword">public</span> <span class="hljs-type">CallAdapter</span><?, ?> <span class="hljs-keyword">get</span>(<span class="hljs-type">Type</span> returnType, <span class="hljs-type">Annotation</span>[] annotations, <span class="hljs-type">Retrofit</span> retrofit) {<br> <span class="hljs-operator">...</span><br> <span class="hljs-keyword">return</span> new <span class="hljs-type">RxJava2CallAdapter</span>(responseType, scheduler, isAsync, isResult, isBody, isFlowable,<br> isSingle, isMaybe, <span class="hljs-literal">false</span>);<br>}<br> <span class="hljs-comment">//RxJava2CallAdapter中</span><br> <span class="hljs-comment">// 转换后 转换前，也就是OkHttpCall</span><br> <span class="hljs-meta">@Override</span> <span class="hljs-keyword">public</span> <span class="hljs-type">Object</span> adapt(<span class="hljs-type">Call</span><<span class="hljs-type">R</span>> call) {<br> <span class="hljs-operator">...</span><br> <span class="hljs-type">Observable</span><?> observable;<br> <span class="hljs-operator">...</span><br> <span class="hljs-keyword">return</span> observable;<br> }<br></code></pre></td></tr></table></figure><p>这个CallAdapter的转换就比较明显了，把retrofit2.Call对象通过适配器转换为了一个实为Observable<?>的Object对象。</p><p>至此，我们可以理解Retrofit根据接口定义动态生产Call网络请求工作对象的原理了，其实就是通过适配器把retrofit2.Call对象转换为目标对象。</p><p>至于适配器转换过程中，如何实现的对象转换，就可以根据需求来自由实现了，比如利用静态代理等，如有必要，我们可以自行开发扩展，Retrofit框架并不限制我们对于适配器的实现方式。</p><h1 id="Retrofit实现原理——函数解析、网络请求和数据转换"><a href="#Retrofit实现原理——函数解析、网络请求和数据转换" class="headerlink" title="Retrofit实现原理——函数解析、网络请求和数据转换"></a>Retrofit实现原理——函数解析、网络请求和数据转换</h1><p>在前面分析中，我们知道了Retrofit的整体工作流程，就是Retrofit用动态代理生成Call网络请求对象，在这个过程中，用适配器把Retrofit底层的retrofit2.Call对象转换为INetApiService中定义的Call网络请求对象（如Flowable）。</p><p>问题是，Retrofit具体是如何知道了INetApiService中定义的Call网络请求对象，如何实现网络请求，以及如何执行的数据转换呢？</p><p>具体过程如下；<br>首先，根据INetApiService中定义的函数，解析函数，得到函数的具体定义，并生成对应的ServiceMethod。<br>然后，根据这个ServiceMethod，实现一个OkHttpCall的Call对象，负责在Retrofit底层实现网络访问。<br>其中，在网络访问返回了网络数据时，根据ServiceMethod实现数据转换。<br>最后，利用上一小节中匹配的适配器，把OkHttpCall对象转换为INetApiService要求的Call网络请求对象。</p><p>所以，我们要了解的就是函数解析、网络请求和数据转换这三个动作，至于最后的适配转换，在上一节中已经分析过了。</p><p><strong>1. 函数解析</strong><br>在接口函数里，用注解描述了输入参数，用Java对象定义了返回值类型，所以对输入参数和返回值，ServiceMethod采取了不同的方式去处理。<br><strong>输入参数</strong><br>输入参数是用来描述url的，它的处理相对简单，ServiceMethod会根据反射得到的Method，取得Annotation注解信息，这些注解是Retrofit自己预定义好的（retrofit2.http.*），ServiceMethod根据预先的定义，直接判断注解所属的逻辑分支，在有网络请求时分情况进行处理，就能得到目标url，http请求头等数据。<br><strong>返回值</strong><br>返回值是需要用CallAdapter去适配的，所以核心在于生成对应的CallAdapter。<br>在Retrofit生成Call网络工作对象时，她通过动态代理获取到了接口函数的Method定义，从这个Method中可以获取函数定义的返回对象类型，由于这个转换是需要CallAdapterFactory生产CallAdapter对象去实现，而Retrofit事先并不知道要使用哪个Factory，所以她是遍历所有的CallAdapterFactory，根据目标函数的返回值类型，让每个Factory都去尝试生产一个CallAdapter，哪个成功就用哪个。</p><p><strong>2. 网络请求</strong><br>OkHttpCall继承的retrofit2.Call接口是为了依赖倒置解耦的，真正的网络请求是由OkHttpCall内部引用的okhttp3.call处理的，这个okhttp3.call是<br>借道ServiceMethod获取的Retrofit中的callFactory，也就是Retrofit中的OkHttpClient。</p><p>整个引用链条是这样的：<br>OkHttpCall–okhttp3.call<br>–><br>ServiceMethod–callFactory<br>–><br>Retrofit.build()–callFactory//**(如未扩展赋值)<strong>new OkHttpClient();<br>–><br>Retrofit.Builder().client(mClient)//</strong>(可能有扩展赋值)**扩展过的OkHttpClient</p><p>最终的网络请求是由OkHttpCall调用OkHttpClient发出的，调用和回调等过程，也就是在OkHttpCall中处理的。</p><p>网络请求的生成过程中，为了使用接口函数中定义的参数，OkHttpCall会调用ServiceMethod来生成Request请求对象，再交给OkHttpCall去处理。</p><p><strong>3. 数据转换</strong><br>因为回调是在OkHttpCall中处理的，所以对回调数据的转换也在OkHttpCall中触发，为了符合接口函数中定义的返回数据类型，OkHttpCall会调用ServiceMethod来转换Response返回数据对象。</p><p>OkHttpCall对返回的网络数据，会调用一个serviceMethod.toResponse(ResponseBody body)函数，函数中执行的是：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><code class="hljs java">R <span class="hljs-title function_">toResponse</span><span class="hljs-params">(ResponseBody body)</span> <span class="hljs-keyword">throws</span> IOException {<br> <span class="hljs-keyword">return</span> responseConverter.convert(body);<br> }<br></code></pre></td></tr></table></figure><p>这个函数可以把原始的okhttp3. ResponseBody数据转换为INetApiService接口中要求的数据类型（如BizEntity类型）。<br>从代码可以看出，实现数据转换的核心对象其实是responseConverter，这个Converter实际上要依次经过Retrofit的建造和ServiceMethod的建造后，才能确定下来的。</p><p><strong>Retrofit建造时添加数据转换工厂</strong><br>Retrofit里有converterFactries列表，这是在我们初始化Retrofit实例时添加的</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-comment">//retrofit对象</span><br><span class="hljs-type">Retrofit</span> <span class="hljs-variable">retrofit</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">Retrofit</span>.Builder()<br> .baseUrl(Config.DOMAIN)<br> .addConverterFactory(GsonConverterFactory.create())<br> .addConverterFactory(YourConverterFactory.create())<span class="hljs-comment">//添加自定义Converter</span><br> .build();<br></code></pre></td></tr></table></figure><p><strong>ServiceMethod建造时设定数据转换器</strong><br>ServiceMethod在建造时，就已经确定了对应的是INetApiService中的哪个函数，所以需要明确设定自己的Converter<R,T>转换对象</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">public</span> ServiceMethod <span class="hljs-title function_">build</span><span class="hljs-params">()</span> {<br> ...<br> responseConverter = createResponseConverter();<br> ...<br> }<br></code></pre></td></tr></table></figure><p>这需要调用Retrofit</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">private</span> Converter<ResponseBody, T> <span class="hljs-title function_">createResponseConverter</span><span class="hljs-params">()</span> {<br> ...<br> retrofit.responseBodyConverter(responseType, annotations);<br> }<br></code></pre></td></tr></table></figure><p>Retrofit会在自己的转换器工厂列表中遍历每个ConverterFactory，尝试根据ServiceMethod所对应的目标数据类型，找到Converter数据转换类</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-keyword">for</span> (<span class="hljs-type">int</span> <span class="hljs-variable">i</span> <span class="hljs-operator">=</span> start, count = converterFactories.size(); i < count; i++) {<br> Converter<ResponseBody, ?> converter =<br> converterFactories.get(i).responseBodyConverter(type, annotations, <span class="hljs-built_in">this</span>);<br> <span class="hljs-keyword">if</span> (converter != <span class="hljs-literal">null</span>) {<br> <span class="hljs-comment">//noinspection unchecked</span><br> <span class="hljs-keyword">return</span> (Converter<ResponseBody, T>) converter;<br> }<br> }<br></code></pre></td></tr></table></figure><p>以Gson转换为例，GsonConverterFactory会通过getAdapter来尝试匹配目标数据类型：</p><pre><code>public <T> TypeAdapter<T> getAdapter(TypeToken<T> type) {...}</code></pre><p>如果可以匹配，那么前面调用serviceMethod.toResponse(ResponseBody body)函数时，会调用</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><code class="hljs java">R <span class="hljs-title function_">toResponse</span><span class="hljs-params">(ResponseBody body)</span> <span class="hljs-keyword">throws</span> IOException {<br> <span class="hljs-keyword">return</span> responseConverter.convert(body);<br>}<br></code></pre></td></tr></table></figure><p>在调用这段代码时，其实就是调用了Gson中最终执行数据转换的代码：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><code class="hljs java"><span class="hljs-meta">@Override</span> <span class="hljs-keyword">public</span> T <span class="hljs-title function_">convert</span><span class="hljs-params">(ResponseBody value)</span> <span class="hljs-keyword">throws</span> IOException {<br> <span class="hljs-type">JsonReader</span> <span class="hljs-variable">jsonReader</span> <span class="hljs-operator">=</span> gson.newJsonReader(value.charStream());<br> <span class="hljs-keyword">try</span> {<br> <span class="hljs-keyword">return</span> adapter.read(jsonReader);<br> } <span class="hljs-keyword">finally</span> {<br> value.close();<br> }<br> }<br></code></pre></td></tr></table></figure><p>总结来说，Retrofit在类的单一职责方面分隔的很好，OkHttpCall类只负责网络交互，凡是需要知道函数定义的，都交给ServiceMethod类去处理，而ServiceMethod类对使用者不公开，因为Retrofit是个外观模式，而所有需要扩展的都在Retrofit的建造者中实现，他们的分工大概是这样的：</p><p><img src="/2022/05/10/retrofit/25f4d8a2.png"></p><p> 三个类的分工</p><p>这三个类分工合作，共同实现了函数解析、网络访问和数据转换，并保留了良好的可扩展性。</p><h1 id="Retrofit实现原理——整体结构与分工实现"><a href="#Retrofit实现原理——整体结构与分工实现" class="headerlink" title="Retrofit实现原理——整体结构与分工实现"></a>Retrofit实现原理——整体结构与分工实现</h1><p>至此，Retrofit的实现细节就已经基本清楚了，他用动态代理去定制接口定义的Call网络工作对象，用适配器去把底层的Call对象转换为目标Call对象，用函数解析/OkHttpClient/数据转换等实现对Call对象的适配转换，并能处理真正的网络请求。<br>这里面涉及的整体结构和角色分工，大概可以这样表示：</p><p><img src="/2022/05/10/retrofit/951b3a66.png"></p><p> 整体结构与角色分工</p><p>其中，扩展适配器、扩展数据转换和扩展OkHttpClient，虽然都是通过Retrofit实现扩展，但真正的使用者是Retrofit内部的ServiceMethod、OkHttpCall和okhttp3.call等类或对象。</p><h1 id="反推Retrofit的设计过程"><a href="#反推Retrofit的设计过程" class="headerlink" title="反推Retrofit的设计过程"></a>反推Retrofit的设计过程</h1><p>如果我们不直接正面分析Retrofit的结构设计和技术细节，而是先从Retrofit的功能和作用入手，倒过来推测Retrofit的目标，进而分析其架构和搭建细节，Retrofit为什么会设计成这样就很好理解了。</p><p>Retrofit的功能是<strong>按照接口定义，自动定制Call网络工作对象</strong>，所以Retrofit的目标应该就是避免为网络访问开发大量的配套代码。</p><p>为了实现这一目标，Retrofit需要分析哪些是易变的，哪些是不变的，然后分别处理。</p><p>由于Retrofit提供网络访问的工作对象，又是服务于具体业务，所以可以分网络访问和具体业务两部分来分析。</p><p><strong>网络访问的不变性</strong><br>对于网络访问来说，不变的是一定有一个实现网络访问的对象，Retrofit选用了自家的OkHttpClient，不过为了把Retrofit和OkHttp两个项目解耦合，Retrofit根据依赖倒置原则，定义了Retrofit自己的Call即<strong>retrofit2.call</strong>，并定义了操作网络请求的<strong>OkHttpCall</strong>。</p><p><strong>网络访问的易变性</strong><br>对于网络访问来说，易变的是网络访问的url、请求方式（get/post等）、Http请求的Header设置与安全设置等，以及返回的数据类型。</p><p>针对易变的url和请求方式，Retrofit使用了<strong>方法注解</strong>的方式，可读性良好，扩展性优异，但这需要实现对接口函数中注解的解析，这样就有了<strong>ServiceMethod</strong>。<br>针对Http请求的各种设置，其实Retrofit没做什么，因为Retrofit使用的OkHttp有<strong>拦截器</strong>机制，可以应付这种变化。<br>针对返回的数据类型，由于目标数据类型与业务有关，是不确定的，Retrofit无法提供一个万能的转换类，所以Retrofit提供了扩展接口，允许开发者自己定义<strong>ConverterFactory和Converter</strong>，去实现潜在的数据类型转换。</p><p><strong>具体业务的不变性</strong><br>对于具体业务来说，不变的是一定要有一个Call网络工作对象，所以Retrofit可以有一个生产对象的机制（像工厂一样）</p><p><strong>具体业务的易变性</strong><br>对于具体业务来说，易变的就是这个Call网络工作对象的类型，不仅有CallBacl回调、可能还有Flowable工作流、或者其他潜在的对象类型。</p><p>针对这种Call对象的易变性，Retrofit也是无法提供一个万能的实现类，所以也是提供了扩展解耦，允许开发者自己定义<strong>CallAdapterFactory和CallAdapter</strong>，去实现潜在的Call类型转换。</p><p>因为这种Call对象的生产需要有大量的配套代码，为了简化代码，Retrofit使用<strong>动态代理</strong>来生产这个对象。</p><p>最后，因为需要处理的方法和对象太多太复杂，需要使用<strong>建造者模式</strong>来把建造过程和使用过程分离开。</p><p>这样倒着走一遍之后，我们再看Retrofit的设计和实现原理，就会觉得水到渠成，对于Retrofit精妙的设计更会有一种切身体会。</p><h1 id="借鉴与启示"><a href="#借鉴与启示" class="headerlink" title="借鉴与启示"></a>借鉴与启示</h1><p>在上文的反推过程中，我们可窥见（瞎猜）Jake大神的一些思路：</p><ol><li>万物皆对象<br> 网络访问后，回调数据是个对象；网络访问本身也是个对象。</li><li>依赖倒置<br> 哪怕是使用自家的OkHttp，哪怕底层调用的始终是OkHttpClient，也需要依赖一个抽象的retrofit2.Call接口，依赖于抽象，而不是依赖于具体。</li><li>单一职责<br> 类的职责需要维持单一，流程需要但是超出自己职责的功能，去调用相关的类实现，比如OkHttpClient和ServiceMethod的各自职责与调用关系。</li><li>迪米特法则<br> 内部实现再复杂，对于外部调用者也只展示他需要的那些功能，例如Retrofit。</li><li>自动>人工<br> 动态代理的使用，可以用自动生成的模板代码，减轻人工编写配套代码的工作量，成本更低，风险更低。</li><li>利用工厂类开放扩展<br> 对于流程确定，但方法不能确定的，利用工厂类，对调用者开放扩展能力。</li><li>利用多个工厂类组成扩展列表<br> 如果1个工厂类不能实现兼得，何不设置一个工厂类列表，在多个工厂类中，看哪个工厂类能解决问题。</li><li>利用建造者模式把建造和使用分离<br> 这样使用者不需要关系复杂的建造过程，例如Retrofit和ServiceMethod。</li><li>利用外观模式减少对复杂子系统的操作<br> 虽然有复杂的子系统协同工作，调用者只需要调用最外层的Retrofit即可。</li><li>其他<br>开放封闭、接口隔离、里式替换、静态代理等设计原则或设计模式都有体现也都很熟悉了，就不再啰嗦。</li></ol><p>最后感叹一下。</p><p>对于网络访问的抽象与优化，实际上是个非常难的课题，在Retrofit之前，大家努力的方向基本上都是Volley/OkHttp这种围绕底层网络访问的工作。<br>因为越底层的东西越容易抽象，越上升到接近业务层，就越容易在纷扰的业务层中迷失。<br>Retrofit能精准地抓到Call网络工作对象这个关键点，并能通过一系列精巧的设计实现对这种类型“飘忽不定”的对象的自动化定制生产，着实令人赞叹。</p><h1 id="参考"><a href="#参考" class="headerlink" title="参考"></a>参考</h1><p><a href="http://square.github.io/retrofit/">Retrofit</a><br><a href="https://www.jianshu.com/p/308f3c54abdd">你真的会用Retrofit2吗?Retrofit2完全教程</a><br><a href="https://www.jianshu.com/p/c1a3a881a144">Retrofit2 源码解析</a><br><a href="https://www.jianshu.com/p/3b5ef96d1a09">Retrofit 框架源码学习</a><br><a href="https://blog.piasy.com/2016/06/25/Understand-Retrofit/">拆轮子系列：拆 Retrofit</a><br><a href="http://blog.csdn.net/self_study/article/details/55050627">Android 动态代理以及利用动态代理实现 ServiceHook</a></p><p>作者：蓝灰_q<br>链接：<a href="https://www.jianshu.com/p/f57b7cdb1c99">https://www.jianshu.com/p/f57b7cdb1c99</a><br>来源：简书<br>著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。</p>]]></content>
<categories>
<category>Java</category>
<category>retrofit</category>
</categories>
<tags>
<tag>retrofit</tag>
<tag>OkHttp</tag>
<tag>squareup</tag>
</tags>
</entry>
<entry>
<title>Hello World</title>
<link href="/2021/06/24/hello-world/"/>
<url>/2021/06/24/hello-world/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><p>Welcome to <a href="https://hexo.io/">Hexo</a>! This is your very first post. Check <a href="https://hexo.io/docs/">documentation</a> for more info. If you get any problems when using Hexo, you can find the answer in <a href="https://hexo.io/docs/troubleshooting.html">troubleshooting</a> or you can ask me on <a href="https://github.com/hexojs/hexo/issues">GitHub</a>.</p><h2 id="Quick-Start"><a href="#Quick-Start" class="headerlink" title="Quick Start"></a>Quick Start</h2><h3 id="Create-a-new-post"><a href="#Create-a-new-post" class="headerlink" title="Create a new post"></a>Create a new post</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo new <span class="hljs-string">"My New Post"</span><br></code></pre></td></tr></table></figure><p>More info: <a href="https://hexo.io/docs/writing.html">Writing</a></p><h3 id="Run-server"><a href="#Run-server" class="headerlink" title="Run server"></a>Run server</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo server<br></code></pre></td></tr></table></figure><p>More info: <a href="https://hexo.io/docs/server.html">Server</a></p><h3 id="Generate-static-files"><a href="#Generate-static-files" class="headerlink" title="Generate static files"></a>Generate static files</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo generate<br></code></pre></td></tr></table></figure><p>More info: <a href="https://hexo.io/docs/generating.html">Generating</a></p><h3 id="Deploy-to-remote-sites"><a href="#Deploy-to-remote-sites" class="headerlink" title="Deploy to remote sites"></a>Deploy to remote sites</h3><figure class="highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><code class="hljs bash">$ hexo deploy<br></code></pre></td></tr></table></figure><p>More info: <a href="https://hexo.io/docs/one-command-deployment.html">Deployment</a></p>]]></content>
</entry>
<entry>
<title>全景图</title>
<link href="/2021/06/23/My-Gallery/"/>
<url>/2021/06/23/My-Gallery/</url>
<content type="html"><![CDATA[<link rel="stylesheet" class="aplayer-secondary-style-marker" href="\assets\css\APlayer.min.css"><script src="\assets\js\APlayer.min.js" class="aplayer-secondary-script-marker"></script><script class="meting-secondary-script-marker" src="\assets\js\Meting.min.js"></script><p>后续放出</p><p><img src="/image/0d5b857819f4b3bb068b9d7142c830bddca9f8427fd8d98dd8d93ffbf15e6374.jpg" alt="1"></p>]]></content>
<tags>
<tag>全景图</tag>
</tags>
</entry>
</search>