相关疑难解决方法(0)

我在Java中有一个JDBC MySQL连接.我的程序适用于简单的查询执行.

如果我运行相同的程序超过10个小时并执行查询,那么我收到以下MySQL异常:

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: 
Connection.close() has already been called. Invalid operation in 
this state.
  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(
  Native Method)
  com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException:
  No operations allowed after statement closed.
  at sun.reflect.NativeConstructorAccessorImpl.newInstance0(
  Native Method)

我没有close()在任何地方使用过方法.我创建了数据库连接并永远打开它并始终执行查询.我没有明确提到连接超时的地方.我无法确定问题所在.

这是我用于数据库连接的代码:

 String driver = PropertyReader.getDriver();
 String url = dbURLPath;
 Class.forName(driver);
 connectToServerDB = DriverManager.getConnection(url);
 connectToServerDB.setAutoCommit(false);

是什么导致了这种例外

我正在尝试连接到我在Java程序中使用MySQL创建的数据库,但它总是失败.

为了举例,这是我的代码:

import java.sql.*;

public class Squirrel {
    public static void main(String[] args) {
        String user;
        String password;
        Connection connection;
        Statement statement;
        try {
            Class.forName("com.mysql.jdbc.Driver");

            connection = DriverManager.getConnection(
                "jdbc:mysql://localhost:3306", user, password);

            statement = connection.createStatement();

            // Other code
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

我能够从IntelliJ中连接到数据库并添加mysql-connector-java-5.1.40.jar添加到项目中,但每次运行程序时都会DriverManager.getConnection()抛出:

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: …