JSch / SSHJ - Connect to an SSH server when a button is clicked

Question

I try to connect to the SSH Unix server when I click the button (the code is written in the actionPerformed () method). I am using JSch to connect to an SSH server. The code is written in the SwingWorker class, as this is a network operation.

private void testConnectionButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                     

        SwingWorker<Boolean, Void> sw = new SwingWorker<Boolean, Void>(){

            @Override
            protected Boolean doInBackground() throws Exception {
                JSch jsch = new JSch();

                String host = "ServerHost";
                String username = "username";
                String password = "password";

                Session session = jsch.getSession(username, host);
                session.setPassword(password);

                session.setTimeout(20000);
                System.out.println("Connecting to server...");
                session.connect();

                return true;
            }

            @Override
            public void done(){
                try {
                    System.out.println(get().toString());
                } catch (Exception ex) {
                    System.out.err(ex);
                } 
            }
        };

        sw.execute();

    }  

But after starting the correct hostname, username and password, I get the following error:

com.jcraft.jsch.JSchException: timeout: socket is not established
    at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)
    at java.util.concurrent.FutureTask.get(FutureTask.java:83)
    at javax.swing.SwingWorker.get(SwingWorker.java:583)

But whenever I run the same code in a standalone program, I mean instead to write the actionPerformed () method if I write it in the usual way and calling main (). This will work. when I integrate the same code with the Click Click actionPerformed () method, it will give me the above exceptions.

Can someone suggest what I am doing wrong here, or any changes should be made to the code.

SSH- "SSHJ", :

java.net.SocketException: Connection reset
    at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)
    at java.util.concurrent.FutureTask.get(FutureTask.java:83)
    at javax.swing.SwingWorker.get(SwingWorker.java:583)

- - ?

Answer 1

, GUI- ( -generics, , JSch). . , ( ).

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;

import com.jcraft.jsch.*;



class SwingWorkerExample {

    JTextField hostField;
    JTextField userNameField;
    JTextField passwordField;
    JPanel panel;


    public SwingWorkerExample() {
        JPanel p = panel = new JPanel(new GridLayout(0,2));
        hostField = new JTextField(20);
        userNameField = new JTextField(20);
        passwordField = new JPasswordField(20);
        JButton testButton = new JButton("connect!");
        testButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent ev) {
                    testConnectionButtonActionPerformed(ev);
                }
            });
        p.add(new JLabel("host:"));
        p.add(hostField);
        p.add(new JLabel("user:"));
        p.add(userNameField);
        p.add(new JLabel("password:"));
        p.add(passwordField);
        p.add(testButton);
    }

    public JPanel getPanel() {
        return panel;
    }

    private void testConnectionButtonActionPerformed(ActionEvent evt) {

        SwingWorker sw = new SwingWorker(){

                protected Object doInBackground() throws Exception {
                    try {
                        JSch jsch = new JSch();

                        String host = hostField.getText();
                        String username = userNameField.getText();
                        String password = passwordField.getText();

                        Session session = jsch.getSession(username, host);
                        session.setPassword(password);
                        session.setConfig("StrictHostKeyChecking", "no");

                        session.setTimeout(20000);
                        System.out.println("Connecting to server...");
                        session.connect();

                        return session;
                    }
                    catch(Exception ex) {
                        ex.printStackTrace();
                        throw ex;
                    }
                }

                public void done(){
                    try {
                        System.out.println(get());
                    } catch (Exception ex) {
                        ex.printStackTrace();
                    }
                }
            };

        sw.execute();

    }


    public static void main(String[] egal) {
        EventQueue.invokeLater(new Runnable(){public void run() {
            SwingWorkerExample ex = new SwingWorkerExample();
            JFrame f = new JFrame("bla");
            f.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
            f.setContentPane(ex.getPanel());
            f.pack();
            f.setVisible(true);
        }});
    }
}