Question

我遇到了一个问题，我不确定它出了什么问题。我正在建立到我的远程服务器的SSH连接，并从那里我试图访问MySQL数据库。 SSH连接正确连接但是，当试图访问MySQL数据库时，我一直收到错误。

在寻求帮助之前，我已经搜索了近一个星期

UPDATE !!!

好吧，所以我能够把它归结为与JSCH有关。我在外部使用putty建立了一个SSH连接并运行代码而没有实际使用JSCH来建立SSH连接而且我能够完全访问数据库。此时，对 JSCH 的任何帮助都会非常有用。

    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)

非常感谢任何帮助。

Answer 1

WOOOOO我开始工作了！所以我做了（我不知道为什么这样做）是我刚刚创建了一个与JSCH建立SSH连接的新类。然后我将所有有趣的SQL内容放在另一个中。从我在连接事件处理程序下的仪表板gui，我首先添加了JSCH连接，之后我连接到SQL DB。谢谢大家的帮助！你真棒！

SSH与MySQL的连接

1 个答案: