Sending commands to remote server through ssh by Java with JSch

Question

I'm trying to set up a class so that I can ssh into a remote server (I have the IP, username, and password) and then send a command like echo "test" and then receive back the output (e.g., "test"). I'm using JSch to do this but I don't understand how to do it.

import com.jcraft.jsch.*;

public class ConnectSSH {

public int execute (String command) {
    
    JSch jsch   = new JSch();
    String ip   = "00.00.00.00";
    String user = "root";
    String pass = "password";
    int port    = 22;

    Session session = jsch.getSession(user, ip, port);   
    session.setPassword(pass);
    session.connect();

    ...

I'm stuck after connecting.

score 25 · Answer 1 · edited May 18 '15 at 08:25

25

Try this:

JSch jsch=new JSch();
Session session=jsch.getSession(remoteHostUserName, RemoteHostName, 22);
session.setPassword(remoteHostpassword);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.connect();

ChannelExec channel=(ChannelExec) session.openChannel("exec");
BufferedReader in=new BufferedReader(new InputStreamReader(channel.getInputStream()));
channel.setCommand("pwd;");
channel.connect();

String msg=null;
while((msg=in.readLine())!=null){
  System.out.println(msg);
}

channel.disconnect();
session.disconnect();

edited May 18 '15 at 08:25

davegson

8,205
4
51
71

answered Jun 14 '13 at 06:39

Shamnad

384
5
16

how to run multiple commands like if I want to execute "cd xx/xx/xx" and then check "pwd" – Vinod Sep 03 '15 at 06:19
Got my answer here: http://stackoverflow.com/questions/5831594/multiple-commands-through-jsch-shell/5831846#5831846, thanks – Vinod Sep 03 '15 at 07:04

score 9 · Answer 2 · answered Oct 10 '14 at 19:08

shamnu's answer above was right. I couldn't add a comment to it, so here are a few examples to enhance his answer. One is how to do a remote execution of 'ls -l', another of 'mkdir', and another of a local to remote copy. All done with version 0.1.51 of jsch (http://www.jcraft.com/jsch/).

  public void remoteLs() throws JSchException, IOException {
    JSch js = new JSch();
    Session s = js.getSession("myusername", "myremotemachine.mycompany.com", 22);
    s.setPassword("mypassword");
    Properties config = new Properties();
    config.put("StrictHostKeyChecking", "no");
    s.setConfig(config);
    s.connect();

    Channel c = s.openChannel("exec");
    ChannelExec ce = (ChannelExec) c;

    ce.setCommand("ls -l");
    ce.setErrStream(System.err);

    ce.connect();

    BufferedReader reader = new BufferedReader(new InputStreamReader(ce.getInputStream()));
    String line;
    while ((line = reader.readLine()) != null) {
      System.out.println(line);
    }

    ce.disconnect();
    s.disconnect();

    System.out.println("Exit code: " + ce.getExitStatus());

  }



  public void remoteMkdir() throws JSchException, IOException {
    JSch js = new JSch();
    Session s = js.getSession("myusername", "myremotemachine.mycompany.com", 22);
    s.setPassword("mypassword");
    Properties config = new Properties();
    config.put("StrictHostKeyChecking", "no");
    s.setConfig(config);
    s.connect();

    Channel c = s.openChannel("exec");
    ChannelExec ce = (ChannelExec) c;

    ce.setCommand("mkdir remotetestdir");
    ce.setErrStream(System.err);

    ce.connect();

    BufferedReader reader = new BufferedReader(new InputStreamReader(ce.getInputStream()));
    String line;
    while ((line = reader.readLine()) != null) {
      System.out.println(line);
    }

    ce.disconnect();
    s.disconnect();

    System.out.println("Exit code: " + ce.getExitStatus());

  }

  public void remoteCopy() throws JSchException, IOException, SftpException {
    JSch js = new JSch();
    Session s = js.getSession("myusername", "myremotemachine.mycompany.com", 22);
    s.setPassword("mypassword");
    Properties config = new Properties();
    config.put("StrictHostKeyChecking", "no");
    s.setConfig(config);
    s.connect();

    Channel c = s.openChannel("sftp");
    ChannelSftp ce = (ChannelSftp) c;

    ce.connect();

    ce.put("/home/myuser/test.txt","test.txt");

    ce.disconnect();
    s.disconnect();    
  }

Just a note, if all you're doing is file operations you can use [ChannelSftp](http://epaul.github.io/jsch-documentation/simple.javadoc/com/jcraft/jsch/ChannelSftp.html) which provides methods like cd(), mkdir(), and put(). — Loren_, Aug 25 '15 at 15:46

score 2 · Answer 3 · edited May 23 '17 at 12:02

I suggest looking at the hidden example on the JCraft website: http://www.jcraft.com/jsch/examples/UserAuthKI.java

Their example prompts for username, hostname, password, so it is ready to test out of the box. I ran it on my network and was able to connect to an AIX server without changing any code.

Note, their example has a problem (this may be why it is hidden).. it does not ever close the channel. If you send 'exit' the server will disconnect you, but the channel object stays open and your Java program never exits. I have provided a fix for that here: Never ending of reading server response using jSch

score -1 · Answer 4 · answered Feb 24 '16 at 11:13

 1. List item

import java.io.InputStream;

import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;

public class SSHCommandExecutor {

    /**
     * @param args
     */
    public static void main(String[] args) {
        String host="10.75.81.21";
        String user="root";
        String password="Avaya_123";
        String command1="ls -l";
        try{

            java.util.Properties config = new java.util.Properties(); 
            config.put("StrictHostKeyChecking", "no");
            JSch jsch = new JSch();
            Session session=jsch.getSession(user, host, 22);
            session.setPassword(password);
            session.setConfig(config);
            session.connect();
            System.out.println("Connected");

            Channel channel=session.openChannel("exec");
            ((ChannelExec)channel).setCommand(command1);
            channel.setInputStream(null);
            ((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));
              }`enter code here`
              if(channel.isClosed()){
                System.out.println("exit-status: "+channel.getExitStatus());
                break;
              }
              try{Thread.sleep(1000);}catch(Exception ee){}
            }
            channel.disconnect();
            session.disconnect();
            System.out.println("DONE");
        }catch(Exception e){
            e.printStackTrace();
        }

    }


 1. List item

}

Can you please elaborate on your solution? – CAFEBABE Feb 24 '16 at 11:30 — CAFEBABE, Feb 24 '16 at 11:30

Sending commands to remote server through ssh by Java with JSch

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