JDBC Mysql SSH Connection, Url cannot be null

Question

I am creating an application and I need to connect to a remote MySql DB. I am using JSch to connect via SSH. I am able to connect via JSch, however when I try to connect to my database I keep getting errors.

public void connectSSH() {
    int lport = 5656;
    String rhost = "host"; //not actual host
    String host = "host"; //not actual host
    int rport = 3306;
    String user = "user"; //not actual user
    String password = "*********";
    String dbuserName = "user"; //not actual user
    String dbpassword = "********";
    String driverName = "com.mysql.jdbc.Driver";
    String url = "jdbc:mysql://127.0.0.1:" + rport + "?user=" + dbuserName + "&password=" + dbpassword + "&useSSL=true";
    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(driverName).newInstance();
        conn = DriverManager.getConnection(url);
        System.out.println("Database connection established");
        System.out.println("DONE");
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (conn != null && !conn.isClosed()) {
                System.out.println("Closing Database Connection");
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        if (session != null && session.isConnected()) {
            System.out.println("Closing SSH Connection");
            session.disconnect();
        }
    }
}

Output:

Connected
localhost:5656 -> rhost:3306
Port Forwarded
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago.The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2188)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2221)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2016)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:776)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:270)
at com.ej.ozyazgan.classes.SqlHelper.connectSSH(SqlHelper.java:176)
at com.ej.ozyazgan.classes.MainController.initialize(MainController.java:52)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2566)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at com.ej.ozyazgan.classes.Main.start(Main.java:13)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:301)
... 43 more
Closing SSH Connection
The url cannot be null

I'm not totally happy about this closure as duplicate. The error here is fairly specific to the use of SSH and a local/remote port mixup, I voted to close for another reason, specifically that it was basically a typo. @MarkRotteveel — user207421, May 09 '18 at 23:58

user207421 · Answer 1 · 2018-05-09T03:07:02.100

0

Caused by: java.net.ConnectException: Connection refused: connect

You didn't read the stack trace. The actual error here is 'connection refused'. The port in the JDBC URL should be the local SSH forwarding port, not the remote port.

edited May 09 '18 at 03:07

answered May 08 '18 at 21:30

user207421

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JDBC Mysql SSH Connection, Url cannot be null

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