SonarQube 不斷抱怨 Use try-with-resources 或在“finally”子句中關閉此“PreparedStatement”

Question

我正在嘗試根據用戶的 ID 從表中獲取電子郵件。 但是，SonarQube 一直在抱怨Use try-with-resources or close this "PreparedStatement" in a "finally" clause我已經擁有Use try-with-resources or close this "PreparedStatement" in a "finally" clause 。 我已經看過這里和其他地方的答案，但這些解決方案對我不起作用。 這是代碼：

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;
    }

我也嘗試將PreparedStatement preparedStatement = this.connection.prepareStatement(sql)包裝在另一個 try catch 或嵌套 try-catch 中，但沒有任何嘗試有效。

Answer 1

您可以嘗試（嘗試使用資源）

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;
    }

Answer 2

setString可能會拋出SQLException 。 如果語句准備成功，然后setString拋出異常，它將在try塊之外執行，並且該語句將永遠不會被關閉。 將prepareStatement移動到嵌套的try應該沒問題，只要你在正確的finally塊中有clsoe （並且沒有看到你做了什么，很難說為什么 SonarQube 抱怨它），但老實說，使用 try-with -resource 語法會更簡潔。 請注意，順便說一下， ResultSet也應該關閉：

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;
}