java socket问题 客户端得不到消息求解啊

代码如下

ServerSocket service = new ServerSocket(8888);
   BufferedOutputStream output;
   Scanner sc;
   BufferedInputStream input ;
   Socket client;
   while(true){
    client = service.accept();
    input = new  BufferedInputStream(client.getInputStream());
       output = new BufferedOutputStream(client.getOutputStream());
    sc = new Scanner(input);
    System.out.println("用户上线了");
    while(true){
    String line = sc.nextLine();

    System.out.println(line);
    output.write(line.getBytes());//返回消息给客户端,我用的telnet 127.0.0.1 8888连接   serversocket的
     if(line.toString().startsWith("end")){
      System.out.println("as");
      client.close();

output.write() 之后还要加 output.flush(); 刷过去啊, 不然的话他还在缓冲区的