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Mydb #358

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11 changes: 11 additions & 0 deletions pom.xml

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revert this. we should keep 1 blank line at the EOF

Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,16 @@
</maven.checkstyle.plugin.configLocation>
</properties>

<dependencies>
<!-- https://mvnrepository.com/artifact/com.mysql/mysql-connector-j -->
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
<version>8.0.33</version>
</dependency>

</dependencies>

<build>
<plugins>
<plugin>
Expand Down Expand Up @@ -55,4 +65,5 @@
</plugins>
</pluginManagement>
</build>

</project>
37 changes: 37 additions & 0 deletions src/main/java/mate/academy/Main.java
Original file line number Diff line number Diff line change
@@ -1,7 +1,44 @@
package mate.academy;

import java.math.BigDecimal;
import java.util.List;
import java.util.Optional;
import mate.academy.dao.BookDao;
import mate.academy.lib.Injector;
import mate.academy.model.Book;

public class Main {
private static final Injector INJECTOR = Injector.getInstance("mate.academy");
private static final Book BOOK_1 = new Book("OnePiece", new BigDecimal(195));

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remove these constants

private static final Book BOOK_1_UPDATE = new Book(1L, "OnePice", new BigDecimal(250));
private static final Book BOOK_2 = new Book("Naruto", new BigDecimal(235));
private static final Book BOOK_3 = new Book("Jujutsu Kaisen", new BigDecimal(243));

public static void main(String[] args) {
BookDao bookDao = (BookDao) INJECTOR.getInstance(BookDao.class);

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Let's create list of books here

Suggested change
List<Book> books = List.of(
new Book(...

bookDao.create(BOOK_1);
bookDao.create(BOOK_2);
bookDao.create(BOOK_3);

bookDao.update(BOOK_1_UPDATE);

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return updated book and print it


List<Book> books = bookDao.findAll();
System.out.println("All books:");
for (Book book : books) {
System.out.println(book);
}

Optional<Book> findById = bookDao.findById(1L);
System.out.println("Book found id: " + findById);

bookDao.deleteById(3L);

List<Book> listAfterDelete = bookDao.findAll();
System.out.println("List after delete by id:");
for (Book book : listAfterDelete) {
System.out.println(book);
}

}
}
17 changes: 17 additions & 0 deletions src/main/java/mate/academy/dao/BookDao.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,17 @@
package mate.academy.dao;

import java.util.List;
import java.util.Optional;
import mate.academy.model.Book;

public interface BookDao {
Book create(Book book);

Optional<Book> findById(Long id);

List<Book> findAll();

Book update(Book book);

boolean deleteById(Long id);
}
99 changes: 99 additions & 0 deletions src/main/java/mate/academy/dao/BookDaoImpl.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,99 @@
package mate.academy.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import mate.academy.lib.Dao;
import mate.academy.model.Book;
import mate.academy.util.ConnectionUtil;

@Dao
public class BookDaoImpl implements BookDao {
@Override
public Book create(Book book) {
String query = "INSERT INTO books (title, price) VALUES (?, ?)";
try (Connection connection = ConnectionUtil.getConnection();
PreparedStatement preparedStatement = connection.prepareStatement(query,
PreparedStatement.RETURN_GENERATED_KEYS)) {
preparedStatement.setString(1, book.getTitle());
preparedStatement.setBigDecimal(2, book.getPrice());
preparedStatement.executeUpdate();

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Suggested change
preparedStatement.executeUpdate();
int affectedRows = statement.executeUpdate();
if (affectedRows < 1) {
throw new DataProcessingException(
"Expected to insert at least 1 row, but 0 was inserted");
}

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Better use this case

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Not fixed

ResultSet resultSet = preparedStatement.getGeneratedKeys();
if (resultSet.next()) {
book.setId(resultSet.getLong(1));

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Suggested change
book.setId(resultSet.getLong(1));
Long id = generatedKeys.getObject(1, Long.class);
book.setId(id);

Check common mistakes file

}
return book;
} catch (SQLException e) {
throw new RuntimeException("Failed to create a book", e);

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Suggested change
throw new RuntimeException("Failed to create a book", e);
throw new DataProcessingException("Failed to create a book", e);

Check all places and use DataProcessingException

}
}

@Override
public Optional<Book> findById(Long id) {
String query = "SELECT * FROM books WHERE id = ?";
try (Connection connection = ConnectionUtil.getConnection();
PreparedStatement preparedStatement = connection.prepareStatement(query)) {
preparedStatement.setLong(1, id);
ResultSet resultSet = preparedStatement.executeQuery();
if (resultSet.next()) {
return Optional.of(new Book(
resultSet.getLong("id"),
resultSet.getString("title"),
resultSet.getBigDecimal("price")));
}
return Optional.empty();
} catch (SQLException e) {
throw new RuntimeException("Failed to find a book by id: " + id, e);
}
}

@Override
public List<Book> findAll() {
String query = "SELECT * FROM books";
try (Connection connection = ConnectionUtil.getConnection();
PreparedStatement preparedStatement = connection.prepareStatement(query)) {
ResultSet resultSet = preparedStatement.executeQuery();
List<Book> books = new ArrayList<>();
while (resultSet.next()) {
books.add(new Book(
resultSet.getLong("id"),
resultSet.getString("title"),
resultSet.getBigDecimal("price")));
}
return books;
} catch (SQLException e) {
throw new RuntimeException("Failed to find all books", e);
}
}

@Override
public Book update(Book book) {
String query = "UPDATE books SET title = ?, price = ? WHERE id = ?";
try (Connection connection = ConnectionUtil.getConnection();
PreparedStatement preparedStatement = connection.prepareStatement(query)) {

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The same with Try-w-resources

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Not fixed

preparedStatement.setString(1, book.getTitle());
preparedStatement.setBigDecimal(2, book.getPrice());
preparedStatement.setLong(3, book.getId());
preparedStatement.executeUpdate();

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Suggested change
preparedStatement.executeUpdate();
int affectedRows = statement.executeUpdate();
if (affectedRows < 1) {
throw new DataProcessingException(
"Expected to update at least 1 row, but 0 was updated.");
}

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Not fixed

return book;
} catch (SQLException e) {
throw new RuntimeException("Failed to update a book", e);
}
}

@Override
public boolean deleteById(Long id) {
String query = "DELETE FROM books WHERE id = ?";
try (Connection connection = ConnectionUtil.getConnection();
PreparedStatement preparedStatement = connection.prepareStatement(query)) {
preparedStatement.setLong(1, id);
return preparedStatement.executeUpdate() > 0;
} catch (SQLException e) {
throw new RuntimeException("Failed to delete a book with id: " + id, e);
}
}
}
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
package mate.academy.exception;

public class DataProcessingException extends RuntimeException {
public DataProcessingException(String message, Throwable ex) {
super(message, ex);
}
}
53 changes: 53 additions & 0 deletions src/main/java/mate/academy/model/Book.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,53 @@
package mate.academy.model;

import java.math.BigDecimal;

public class Book {
private Long id;
private String title;
private BigDecimal price;

public Book(String title, BigDecimal price) {
this.title = title;
this.price = price;
}

public Book(Long id, String title, BigDecimal price) {
this.id = id;
this.title = title;
this.price = price;
}

public Long getId() {
return id;
}

public void setId(Long id) {
this.id = id;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public BigDecimal getPrice() {
return price;
}

public void setPrice(BigDecimal price) {
this.price = price;
}

@Override
public String toString() {
return "Book {"
+ "id - " + id
+ ", title - '" + title + '\''
+ ", price - " + price
+ "}";
}
}
28 changes: 28 additions & 0 deletions src/main/java/mate/academy/util/ConnectionUtil.java
Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
package mate.academy.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class ConnectionUtil {
private static final String DB_URL = "jdbc:mysql:"

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Suggested change
private static final String DB_URL = "jdbc:mysql:"
private static final String DB_URL = "jdbc:mysql://localhost:3306/mydatabase?serverTimezone=UTC";

any concatenation creating new String object.

+ "//localhost:3306/mydatabase?serverTimezone=UTC";
private static final Properties DB_PROPERTIES;

static {
DB_PROPERTIES = new Properties();
DB_PROPERTIES.put("user", "mary");
DB_PROPERTIES.put("password", "1905Z");

try {
Class.forName("com.mysql.cj.jdbc.Driver");
} catch (ClassNotFoundException e) {
throw new RuntimeException("Can not load JDBC driver", e);
}
}

public static Connection getConnection() throws SQLException {
return DriverManager.getConnection(DB_URL, DB_PROPERTIES);
}
}
6 changes: 6 additions & 0 deletions src/main/resources/init_db.sql
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
CREATE TABLE IF NOT EXISTS books (
id BIGINT NOT NULL AUTO_INCREMENT,
title VARCHAR(255),
price INT,
PRIMARY KEY(id)
);
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