Question

我非常确定我正在关闭finally块中的con，rs，stmt。但似乎在尝试执行更新的第4次尝试时出现“太多连接”错误。

public boolean setUserSettings(UserSettings userSettings)
{
    ResultSet rs = null;
    Connection con = null;
    PreparedStatement stmt = null;
    String _query;

    try
    {
        System.out.println("total current connections: " + dataSource.getActive());
        con = dataSource.getConnection();
        _query = Util.readIn("/sql/select/selectUserSettingsCount.sql", MySqlPersistence.class);
        stmt = con.prepareStatement(_query);
        stmt.setString(1, userSettings.user);

        rs = stmt.executeQuery();
        boolean found = rs.next() && rs.getInt(1) == 1;

        if (!found)
        {
            _query = Util.readIn("/sql/insert/setUserSettings.sql", MySqlPersistence.class);
            stmt = con.prepareStatement(_query);
            stmt.setString(1, userSettings.user);
            stmt.setBoolean(2, userSettings.isActive);
            stmt.setString(3, userSettings.phone);
            stmt.setString(4, userSettings.phone2);
            stmt.setString(5, userSettings.phone3);
            stmt.setString(6, userSettings.contact_strategy);
        }
        else
        {               
            _query = Util.readIn("/sql/update/updateUserSettings.sql", MySqlPersistence.class);
            stmt = con.prepareStatement(_query);
            stmt.setString(1, userSettings.phone);
            stmt.setString(2, userSettings.phone2);
            stmt.setString(3, userSettings.phone3);
            stmt.setString(4, userSettings.user);
        }

        int success = stmt.executeUpdate();
        if (found && success == 1)
        {
            return true;
        }
        else
        {                
            return false;
        }
    }
    catch (Exception e)
    {            
        e.printStackTrace();
        return false;
    }
    finally
    {
        try { if (rs != null) System.out.println("closing rs"); rs.close(); } catch (SQLException e) { }
        try { if (stmt != null) System.out.println("closing stmt"); stmt.close(); } catch (SQLException e) { }
        try { if (con != null) System.out.println("closing con"); con.close(); } catch (SQLException e) { }
    }
}

Answer 1

每个方法调用创建2个语句，但只关闭1.在输入第一个大if块之前，应关闭现有语句。

更新：

经过进一步反思，我发现你的代码中有另一个错误。这种模式被破坏了：

if (con != null) System.out.println("closing con"); con.close();

事实上，它是一个很好的例子，为什么你应该总是使用if块的大括号。重新格式化，此代码为：

if (con != null) 
    System.out.println("closing con"); 
con.close();

然而，你真正想要的是：

if (con != null) {
    System.out.println("closing con"); 
    con.close();
}

即使dataSource.getActive（）返回0，“Too Many Connections”错误？

1 个答案: