Jv jdbc intro solution #378
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| Book update(Book book); | ||
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| boolean deleteById(Long id); | ||
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| @Dao | ||
| public class BookDaoImpl implements BookDao { | ||
| private static final String URL = "jdbc:mysql://localhost:3306/test"; |
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It's better to create ConnectionUtil class to establish connection to DB
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| try (ResultSet generatedKeys = preparedStatement.getGeneratedKeys()) { | ||
| if (generatedKeys.next()) { | ||
| long id = generatedKeys.getLong(1); |
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| long id = generatedKeys.getLong(1); | |
| long id = generatedKeys.getObject(1, Long.class); | |
| book.setId(id); | |
| return book; |
| long id = generatedKeys.getLong(1); | ||
| return new Book(id, book.getTitle(), book.getPrice()); | ||
| } else { | ||
| throw new RuntimeException("Failed to retrieve the generated key"); |
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| throw new RuntimeException("Failed to retrieve the generated key"); | |
| throw new DataProcessingException("Failed to retrieve the generated key"); |
| } | ||
| } | ||
| } catch (SQLException e) { | ||
| throw new RuntimeException("Cannot create a connection to the DB", e); |
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| throw new RuntimeException("Cannot create a connection to the DB", e); | |
| throw new DataProcessingException("Can't add a new book, " + book, e); |
Check all places where you are using RuntimeEx
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| try (ResultSet resultSet = preparedStatement.executeQuery()) { | ||
| if (resultSet.next()) { | ||
| String title = resultSet.getObject("title", String.class); |
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Create separate method to map ResultSet to book to avoid duplication in findById and findAll methods
| } | ||
| } | ||
| } catch (SQLException e) { | ||
| throw new RuntimeException("Cannot create a connection to the DB", e); |
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Change message according to the logic of method (see example above)
Check everywhere
src/main/resources/init_db.sql
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| CREATE TABLE `books`( | |||
| `id` INT NOT NULL AUTO_INCREMENT, | |||
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| `id` INT NOT NULL AUTO_INCREMENT, | |
| `id` BIGINT AUTO_INCREMENT, |
| } | ||
| } | ||
| } catch (SQLException e) { | ||
| throw new DataProcessingException("Cannot create a connection to the DB", e); |
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Let's change messages to describe more informative the issue like:
Can't add a book:
Can't find book by id ....
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Thank you for comment but I little bit disagree with you because in this case we make try catch for Connection field and if we catch some exception this exception will related to Connection field which is responsible for connection to the database.
Am I right?
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SQLException is related not only to Connection, but to PreparedStatement also.
It's better to use try-catch for public static Connection getConnection() and provide informative message about connection issue, and in BookDaoImpl catch provide information about
Can't add a book:
Can't find book by id ....
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| package mate.academy.dao; | |||
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| package mate.academy.dao; | |
| package mate.academy.util; |
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| package mate.academy.dao; | |||
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| package mate.academy.dao; | |
| package mate.academy.exception; |
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