java ssh免密登录

package com.meituan.stabletest.sshtest;
import java.io.InputStream;

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


/**
 * Hello world!
 *
 */
public class App 
{
    public static void main(String[] args) {
        String host="192.168.56.101";
        String user="root";
        String command1="ls -ltr";
        try{
            
            java.util.Properties config = new java.util.Properties(); 
            config.put("StrictHostKeyChecking", "no");
            JSch jsch = new JSch();
            Session session=jsch.getSession(user, host, 22);
            jsch.setKnownHosts("~/.ssh/known_hosts");
            jsch.addIdentity("~/.ssh/id_rsa");
            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));
              }
              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();
        }

    }
}