Linux cmd执行后的java读取输出将进入无限循环

Question

我正在从jsch执行cmd，一旦命令完成，我需要显示命令输出。在读取命令输出时，它需要很长时间，而且即使在执行命令之后，它的ns也不会来自while循环。以下是我的代码：

java.util.Properties config = new java.util.Properties(); 
        config.put("StrictHostKeyChecking", "no");


        JSch jsch = new JSch();
        session=jsch.getSession(user, host, 22);
        session.setConfig("PreferredAuthentications","publickey,keyboard-interactive,password");
        session.setPassword(password);

        session.setConfig(config);
        session.connect();
        System.out.println("Connected");

        channel=session.openChannel("shell");
        OutputStream ops = channel.getOutputStream();
        PrintStream ps = new PrintStream(ops, true);

         channel.connect();
         ps.println(cmd);
        InputStream in=channel.getInputStream();
        byte[] tmp=new byte[1024];
        while(channel.getExitStatus() == -1){
          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(3000);}catch(Exception ee){}
        }