1. 技术文章
  2. com.jcraft.jsch.JSchException: java.net.ConnectException: Connection refused: connect

com.jcraft.jsch.JSchException: java.net.ConnectException: Connection refused: connect

由 你离开我真会死。 提交于 2019-12-06 05:00:05

You're attempting to connect to your local host via the SSH protocol. With JSCH this isn't exactly socket programming, but your issue is related to socket programming.

Essentially your issue is that your program is trying to connect to a port which isn't open, specifically in this instance it's port 22. You don't have an SSH server so your SSH client can't do anything. You're making a telephone call to someone who doesn't have a phone.

To resolve this issue you need to either find a test server which does have ssh running on it to do your development against or install an ssh server on your local PC. For a windows box your best bet is cygwin, which will allow you to emulate a posix system and run SSHD on your local machine. A google search for cygwin and sshd will provide you with examples of how to set this up.

Kelly

I have no idea why but after i can putty to my own localhost, although the above (Sample code, and Thank you for providing the code) i faces the error but the following code (Again, thank you for providing the code. This code is from JCraft, if im not confused, works! i managed to send the command 'help'). Lots of thanks to #chris midolo for providing an answer and #Robby Cornelissen for commenting... although i become more confused (So... SSH means a Server and a Client(?) Sigh... and i though remote access means as long as my computer is on, i can access it from else where... So my computer, in order to be accessed from elsewhere, must also have some kind of server running... OMG! my head hurts....)

Please note that apart from 'help' using other command will result in 'Unable to execute command or shell on remote system: Failed to Execute process. As per http://www.freesshd.com/index.php?ctt=forum&action=view&topic=1186152755, you need to use cmd /c dir and to execute my bat file, i need to use C:\Users\kellyseo\sampling.bat (If i just uses sampling.bat, it shows an error)

My Batch File content is as follows:

ECHO RUNNING kellyseo SAMPLING.BAT
@ECHO OFF
CD C:\Users\kellyseo\Desktop
set ldt=kellyseo folder version executed on %date% %time%
echo %ldt%>> logs.txt
EXIT

I actually have 2 version of the same file (one i put at desktop) then i can use just 'sampling.bat'

If you do not like to many prompts, apart from removing the prompts, you might also need the following code if you faces this com.jcraft.jsch.JSchException: UnknownHostKey (Thanks to com.jcraft.jsch.JSchException: UnknownHostKey)

session.setPassword(password);
java.util.Properties config = new java.util.Properties(); 
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect();

**NOTE: #1 prompt = enter password. #2 prompt = enter command. username is 'user1' 

/* -*-mode:java; c-basic-offset:2; indent-tabs-mode:nil -*- */
/**
 * This program will demonstrate remote exec.
 *   $ CLASSPATH=.:../build javac Exec.java 
 *   $ CLASSPATH=.:../build java Exec
 * You will be asked username, hostname, displayname, passwd and command.
 * If everything works fine, given command will be invoked 
 * on the remote side and outputs will be printed out.
 *
 */
import com.jcraft.jsch.*;
import java.awt.*;
import javax.swing.*;
import java.io.*;

public class Exec{
  public static void main(String[] arg){
    try{
      JSch jsch=new JSch();  
/*
      String host=null;
      if(arg.length>0){
        host=arg[0];
      }
      else{
        host=JOptionPane.showInputDialog("Enter username@hostname",
                                         System.getProperty("user.name")+
                                         "@localhost"); 
      }
      String user=host.substring(0, host.indexOf('@'));
      host=host.substring(host.indexOf('@')+1);
*/
      String user1 = "user1";
      String host1 = "127.0.0.1";
      Session session=jsch.getSession(user1, host1, 22);

      /*
      String xhost="127.0.0.1";
      int xport=0;
      String display=JOptionPane.showInputDialog("Enter display name", 
                                                 xhost+":"+xport);
      xhost=display.substring(0, display.indexOf(':'));
      xport=Integer.parseInt(display.substring(display.indexOf(':')+1));
      session.setX11Host(xhost);
      session.setX11Port(xport+6000);
      */

      // username and password will be given via UserInfo interface.
      UserInfo ui=new MyUserInfo();
      session.setUserInfo(ui);
      session.connect();

      String command=JOptionPane.showInputDialog("Enter command", 
                                                 "set|grep SSH");

      Channel channel=session.openChannel("exec");
      ((ChannelExec)channel).setCommand(command);

      // X Forwarding
      // channel.setXForwarding(true);

      //channel.setInputStream(System.in);
      channel.setInputStream(null);

      //channel.setOutputStream(System.out);

      //FileOutputStream fos=new FileOutputStream("/tmp/stderr");
      //((ChannelExec)channel).setErrStream(fos);
      ((ChannelExec)channel).setErrStream(System.err);

      InputStream in=channel.getInputStream();

      channel.connect();

      byte[] tmp=new byte[1024];
      while(true){
        while(in.available()>0){
          int i=in.read(tmp, 0, 1024);
          if(i<0)break;
          System.out.print(new String(tmp, 0, i));
        }
        if(channel.isClosed()){
          if(in.available()>0) continue; 
          System.out.println("exit-status: "+channel.getExitStatus());
          break;
        }
        try{Thread.sleep(1000);}catch(Exception ee){}
      }
      channel.disconnect();
      session.disconnect();
    }
    catch(Exception e){
      System.out.println(e);
    }
  }

  public static class MyUserInfo implements UserInfo, UIKeyboardInteractive{
    public String getPassword(){ return passwd; }
    public boolean promptYesNo(String str){
      Object[] options={ "yes", "no" };
      int foo=JOptionPane.showOptionDialog(null, 
             str,
             "Warning", 
             JOptionPane.DEFAULT_OPTION, 
             JOptionPane.WARNING_MESSAGE,
             null, options, options[0]);
       return foo==0;
    }

    String passwd;
    JTextField passwordField=(JTextField)new JPasswordField(20);

    public String getPassphrase(){ return null; }
    public boolean promptPassphrase(String message){ return true; }
    public boolean promptPassword(String message){
      Object[] ob={passwordField}; 
      int result=
        JOptionPane.showConfirmDialog(null, ob, message,
                                      JOptionPane.OK_CANCEL_OPTION);
      if(result==JOptionPane.OK_OPTION){
        passwd=passwordField.getText();
        return true;
      }
      else{ 
        return false; 
      }
    }
    public void showMessage(String message){
      JOptionPane.showMessageDialog(null, message);
    }
    final GridBagConstraints gbc = 
      new GridBagConstraints(0,0,1,1,1,1,
                             GridBagConstraints.NORTHWEST,
                             GridBagConstraints.NONE,
                             new Insets(0,0,0,0),0,0);
    private Container panel;
    public String[] promptKeyboardInteractive(String destination,
                                              String name,
                                              String instruction,
                                              String[] prompt,
                                              boolean[] echo){
      panel = new JPanel();
      panel.setLayout(new GridBagLayout());

      gbc.weightx = 1.0;
      gbc.gridwidth = GridBagConstraints.REMAINDER;
      gbc.gridx = 0;
      panel.add(new JLabel(instruction), gbc);
      gbc.gridy++;

      gbc.gridwidth = GridBagConstraints.RELATIVE;

      JTextField[] texts=new JTextField[prompt.length];
      for(int i=0; i<prompt.length; i++){
        gbc.fill = GridBagConstraints.NONE;
        gbc.gridx = 0;
        gbc.weightx = 1;
        panel.add(new JLabel(prompt[i]),gbc);

        gbc.gridx = 1;
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.weighty = 1;
        if(echo[i]){
          texts[i]=new JTextField(20);
        }
        else{
          texts[i]=new JPasswordField(20);
        }
        panel.add(texts[i], gbc);
        gbc.gridy++;
      }

      if(JOptionPane.showConfirmDialog(null, panel, 
                                       destination+": "+name,
                                       JOptionPane.OK_CANCEL_OPTION,
                                       JOptionPane.QUESTION_MESSAGE)
         ==JOptionPane.OK_OPTION){
        String[] response=new String[prompt.length];
        for(int i=0; i<prompt.length; i++){
          response[i]=texts[i].getText();
        }
    return response;
      }
      else{
        return null;  // cancel
      }
    }
  }
}

If you are using mac there is a possibility that you haven't allowed remote logins to the server(in this case your machine). Go to System preferences-> Sharing and enable remote login. Also add the user that you want to work with.

标签
sockets
jsch
易学教程内所有资源均来自网络或用户发布的内容，如有违反法律规定的内容欢迎反馈！
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!