java - SSH 连接到 MySQL

Question

我遇到了一个问题，我不确定哪里出了问题。我正在建立到我的远程服务器的 SSH 连接，并试图从那里访问 MySQL 数据库。 SSH 连接正确连接，但是，当尝试访问 MySQL 数据库时，我不断收到错误消息。

在寻求帮助之前，我难以置信地搜索了将近一个星期

更新!!!

好吧，我已经能够将其归结为与 JSCH 有关。我在外部使用 putty 建立了一个 SSH 连接，并在没有实际使用 JSCH 建立 SSH 连接的情况下运行代码，我能够完全访问 teh DB。在这一点上，任何有关 JSCH 的帮助都会非常有帮助。

    int lport=3306;
    String rhost="SERVERNAME";
    String host="SERVERNAME";
    int rport=3306;
    String user="USERNAME";
    String password="SSHPass";
    String dbuserName = "DBUSER";
    String dbpassword = "DBPWD";
    String url = "jdbc:mysql://localhost:3306/dbname";
    String driverName="com.mysql.jdbc.Driver";
    Connection conn = null;
    Session session= null;
    try{
        //Set StrictHostKeyChecking property to no to avoid UnknownHostKey issue
        java.util.Properties config = new java.util.Properties(); 
        config.put("StrictHostKeyChecking", "no");
        JSch jsch = new JSch();
        session=jsch.getSession(user, host, 22);
        session.setPassword(password);
        session.setConfig(config);
        session.connect();
        System.out.println("Connected");
        int assinged_port=session.setPortForwardingL(lport, rhost, rport);
        System.out.println("localhost:"+assinged_port+" -> "+rhost+":"+rport);
        System.out.println("Port Forwarded");

        //mysql database connectivity
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection(url, dbuserName, dbpassword);
        System.out.println ("Database connection established");
        System.out.println("DONE");
    }catch(Exception e){
        e.printStackTrace();
    }finally{
        if(conn != null && !conn.isClosed()){
            System.out.println("Closing Database Connection");
            conn.close();
        }
        if(session !=null && session.isConnected()){
            System.out.println("Closing SSH Connection");
            session.disconnect();
        }
    }

com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

com.mysql.jdbc.CommunicationsException
MESSAGE: Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.io.EOFException
MESSAGE: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.

STACKTRACE:

java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1997)
    at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:573)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1044)
    at com.mysql.jdbc.Connection.createNewIO(Connection.java:2775)
    at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at Data.SQLConnection.getConnection(SQLConnection.java:49)
    at finalproject.Dashboard.jButton1ActionPerformed(Dashboard.java:391)
    at finalproject.Dashboard.access$200(Dashboard.java:37)
    at finalproject.Dashboard$4.actionPerformed(Dashboard.java:221)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6525)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
    at java.awt.Component.processEvent(Component.java:6290)
    at java.awt.Container.processEvent(Container.java:2234)
    at java.awt.Component.dispatchEventImpl(Component.java:4881)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
    at java.awt.Container.dispatchEventImpl(Container.java:2278)
    at java.awt.Window.dispatchEventImpl(Window.java:2750)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

如有任何帮助，我们将不胜感激。

Answer 1

哇哦，我成功了!所以我所做的(我不知道为什么会这样)是我刚刚创建了一个新类，它与 JSCH 建立了 SSH 连接。然后我将所有有趣的 SQL 内容放在另一个中。从连接事件处理程序下的仪表板 gui，我首先添加了 JSCH 连接，然后连接到 SQL DB。谢谢大家的帮助!你们都很棒!