SonarQube 不断抱怨 Use try-with-resources 或在“finally”子句中关闭此“PreparedStatement”答案

【问题标题】：SonarQube keeps complaining about Use try-with-resources or close this "PreparedStatement" in a "finally" clauseSonarQube 不断抱怨 Use try-with-resources 或在“finally”子句中关闭此“PreparedStatement”
【发布时间】：2021-12-09 09:34:40
【问题描述】：

我正在尝试从基于用户 ID 的表中获取电子邮件。但是，SonarQube 一直在抱怨我已经拥有的 Use try-with-resources or close this "PreparedStatement" in a "finally" clause。我已经查看了here 和其他地方的答案，但这些解决方案对我不起作用。代码如下：

public String getUserEmail(String id) throws SQLException {
        String emailAddress = null;
        String sql = "select email from my_table where id=?";
        PreparedStatement preparedStatement = this.connection.prepareStatement(sql);
        preparedStatement.setString(1, id);
        try {
            ResultSet rs = preparedStatement.executeQuery();
            while (rs.next()) {
                emailAddress = rs.getString("email");
            }
        } catch(SQLException e) {
            throw new TuringClientException("Failed to getUserEmail. ", e);
        } finally {
            preparedStatement.close();
        }
        return emailAddress;
    }

我也尝试将 PreparedStatement preparedStatement = this.connection.prepareStatement(sql) 包装在另一个 try catch 或嵌套 try-catch 中，但这些尝试都不起作用。

【问题讨论】：

标签： java sql sonarqube prepared-statement

【解决方案1】：

setString 可能会抛出 SQLException。如果语句准备成功，然后setString 抛出异常，它将在try 块的外部这样做，并且语句将永远不会关闭。将prepareStatement 移动到嵌套的try 应该没问题，只要你在右边的finally 块中有clsoe（并且没有看到你做了什么很难说为什么SonarQube 抱怨它），但老实说，使用 try-with-resource 语法会更整洁。注意，顺便提一下，ResultSet 也应该关闭：

public String getUserEmail(String id) throws SQLException {
    String emailAddress = null;
    String sql = "select email from my_table where id=?";
    try (PreparedStatement preparedStatement = this.connection.prepareStatement(sql) {
        preparedStatement.setString(1, id);
        try (ResultSet rs = preparedStatement.executeQuery()) {
            while (rs.next()) {
                emailAddress = rs.getString("email");
            }
        } catch(SQLException e) {
            throw new TuringClientException("Failed to getUserEmail. ", e);
        }
    }
    return emailAddress;
}

【讨论】：

【解决方案2】：

你可以试试（用资源试试）

public String getUserEmail(String id) throws SQLException {
        String emailAddress = null;
        String sql = "select email from my_table where id=?";
        try(PreparedStatement preparedStatement = this.connection.prepareStatement(sql)) {
            preparedStatement.setString(1, id);
            ResultSet rs = preparedStatement.executeQuery();
            while (rs.next()) {
                emailAddress = rs.getString("email");
            }
        } catch(SQLException e) {
            throw new TuringClientException("Failed to getUserEmail. ", e);
        }
        return emailAddress;
    }

【讨论】：