I am trying to make something from this simple example :
SSH, execute remote commands with Android
I just want to see if I can connect from my android phone to a linux server using SSH but it doesn't work...
Here is my main code :
package com.example.ssh;
import java.util.Properties;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
import android.os.Bundle;
import android.app.Activity;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try
{
JSch jsch = new JSch();
Session session = jsch.getSession("root","192.168.0.26", 22);
session.setPassword("xxxxx");
// Avoid asking for key confirmation
Properties prop = new Properties();
prop.put("StrictHostKeyChecking", "no");
session.setConfig(prop);
session.connect();
}
catch (Exception e)
{
System.out.println(e.getMessage());
}
}
}
What did I do wrong ? I have no error messages and I don't see any SSH connection on my Linux. I added the libraries jsch and jzlib. I have no problem to get connect with a putty session.
EDIT1 : In fact, I found an error which explain why it doesn't work even if I don't know how to resolve the problem. The error is :
android.os.NetworkOnMainThreadException
so it seems to mean that the app can't perform a networking operation on its main thread...
An execution of a shell command via SSH can be done in Java, in just a few lines, using jcabi-ssh: String hello = new Shell. Plain( new SSH( "ssh.example.com", 22, "yegor", "-----BEGIN RSA PRIVATE KEY-----..." ) ).
JSch. JSch is the Java implementation of SSH2 that allows us to connect to an SSH server and use port forwarding, X11 forwarding, and file transfer. Also, it is licensed under the BSD style license and provides us with an easy way to establish an SSH connection with Java.
JSch is a pure Java implementation of SSH2. JSch allows you to connect to an sshd server and use port forwarding, X11 forwarding, file transfer, etc., and you can integrate its functionality into your own Java programs. JSch is licensed under BSD style license.
You have to execute that code in another thread so you don't hang the UI thread is what that exception means. If the UI thread is executing a network call it can't repaint the UI so your users sees a frozen UI that doesn't respond to them while the app is waiting on the network call to finish. Android wants to avoid bad user experiences like this so it prevents you from doing things like this by throwing this exception.
Your onCreate() method should invoke another thread (I'd suggest using an AsyncTask over a raw thread) to perform the SSH connection. Then when it's done it can post the results back to the UI thread and safely update your application's UI from the UI thread.
http://developer.android.com/reference/android/os/AsyncTask.html
chubbsondubs's solution is perfect. I just want to share the code that I made for this problem too for people who want a quick solution:
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new AsyncTask<Integer, Void, Void>(){
@Override
protected Void doInBackground(Integer... params) {
try {
executeRemoteCommand("root", "myPW","192.168.0.26", 22);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}.execute(1);
}
public static String executeRemoteCommand(String username,String password,String hostname,int port)
throws Exception {
JSch jsch = new JSch();
Session session = jsch.getSession(username, hostname, port);
session.setPassword(password);
// Avoid asking for key confirmation
Properties prop = new Properties();
prop.put("StrictHostKeyChecking", "no");
session.setConfig(prop);
session.connect();
// SSH Channel
ChannelExec channelssh = (ChannelExec)
session.openChannel("exec");
ByteArrayOutputStream baos = new ByteArrayOutputStream();
channelssh.setOutputStream(baos);
// Execute command
channelssh.setCommand("lsusb > /home/pi/test.txt");
channelssh.connect();
channelssh.disconnect();
return baos.toString();
}
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With