问使用JSch在远程SSH会话上运行telnet命令后挂起执行

EN

    public static void main(String[] arg) {
    try {
        System.out.println(telnetConnection(command, puttyUserName,
    puttyPassword, puttyHostName));
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static String telnetConnection(String command, String user, String password, String host)
        throws JSchException, Exception {
    JSch jsch = new JSch();
    jsch.addIdentity(puttyPublicKey, puttyPassword);
    Session session = jsch.getSession(user, host, 22);

    session.setConfig("StrictHostKeyChecking", "no");

    session.connect(500);//This timeout is not working as mentioned in the example. Program execution never stops.

    Channel channel = session.openChannel("shell");

    channel.connect(500);

    DataInputStream dataIn = new DataInputStream(channel.getInputStream());
    BufferedReader reader = new BufferedReader(new InputStreamReader(dataIn));
    DataOutputStream dataOut = new DataOutputStream(channel.getOutputStream());
    System.out.println("Starting telnet connection...");
    dataOut.writeBytes("telnet localhost 4444\r\n"); after this no commands executes
    dataOut.writeBytes(command + "\r\n"); 

    dataOut.writeBytes("quit\r\n");

    dataOut.writeBytes("exit\r\n"); // exit from shell
    dataOut.flush();
    String line = reader.readLine(); 
    String result = line + "\n";
    while (!(line = reader.readLine()).equals("Connection closed by foreign host")) 
    {
        result += line + "\n";

        System.out.println("heart beat" + result);
    }

    System.out.println("after while done");
    dataIn.close();
    dataOut.close();
    channel.disconnect();
    session.disconnect();
    System.out.println("done");
    return result;
}