[英]How can I not throw exception at interface method signature If I throw exception in method that implements that interface?
我為每個實體都有 Dao 接口。我也為每個資源實現了這些接口,例如 MYSQL.MYSQL Dao 方法拋出特定的異常,所以我需要在接口層拋出它們,但異常是特定於 Z14498B83DD1667A0C78F4ZF5在接口層?或者我需要改變設計嗎? 例如,我有 UserDao 接口:
public interface UserDao {
boolean insertUser(Connection connection, User user) throws MySQLEXContainer.MySQLDBNotUniqueException, MySQLEXContainer.MySQLDBLargeDataException, MySQLEXContainer.MySQLDBExecutionException, SQLException;
boolean deleteUser(Connection connection,String login) throws MySQLEXContainer.MySQLDBExecutionException, SQLException;
boolean validateUser(Connection connection,String login,String password) throws MySQLEXContainer.MySQLDBExecutionException, SQLException;
User findUser(Connection connection,String login) throws MySQLEXContainer.MySQLDBExecutionException, SQLException;
boolean updateUser(Connection connection,String login,String newPassword) throws MySQLEXContainer.MySQLDBExecutionException, SQLException;
List<User> findAllUser(Connection connection) throws MySQLEXContainer.MySQLDBExecutionException, SQLException;
}
我已經實現了所有這些,但我只展示了一個
MYSQLUserDao class insertUser方法的實現
@Override
public boolean insertUser(Connection connection, User user) throws MySQLEXContainer.MySQLDBNotUniqueException, MySQLEXContainer.MySQLDBLargeDataException, MySQLEXContainer.MySQLDBExecutionException, SQLException {
LOGGER.debug("Insert User Is started");
int rowNum;
ResultSet keys = null;
Connection con;
PreparedStatement statement = null;
try {
String query = QueriesUtil.getQuery("insertUser");
con = connection;
statement = con.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);
statement.setString(1, user.getLogin());
statement.setString(2, PasswordUtil.generateStrongPasswordHash(user.getPassword()));
statement.setString(3, user.getUserType());
statement.setString(4, user.getUserEmail());
rowNum = statement.executeUpdate();
keys = statement.getGeneratedKeys();
if (keys.next()) {
user.setUserId(keys.getInt(1));
}
} catch (SQLException e) {
LOGGER.error(e);
if (e.getErrorCode() == 1062) {
throw new MySQLEXContainer.MySQLDBNotUniqueException(String.format("%s %s", user.getLogin(), user.getUserEmail()), e.getCause());
} else if (e.getErrorCode() == 1406) {
throw new MySQLEXContainer.MySQLDBLargeDataException("Data Is too long", e);
}
throw new MySQLEXContainer.MySQLDBExecutionException("Bad execution", e);
} finally {
ConnectionUtil.oneMethodToCloseThemAll(keys, statement, null);
LOGGER.debug("Close all resources");
}
return rowNum > 0;
}
如果我想為 Oracle 實現 dao,我需要向 OracleDb 拋出特定異常,因此接口的方法簽名將有太多異常。 我該如何解決這個問題?
我至少可以想到兩種方法來實現這一目標:
閱讀本文以了解處理異常的一些已知最佳實踐: https://dzone.com/articles/9-best-practices-to-handle-exceptions-in-java
我相信你的方法太老了。 幾乎所有的開發者都使用某種 ORM,例如 Hibernate、MyBatis 等...
所以,在我看來,你必須使用 ORM。 它節省了很多時間。 例如,如果您使用 Maven 項目,只需將 hibernate 依賴項添加到您的 pom.xml
或者
您必須編寫自定義異常 class 並使用自定義 class。
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