帮忙看看有什么问题，文件拷贝地方是不是不对，运行无结果
客户端向服务器上传文件
服务端代码
public static void main(String[] args) throws IOException {
  
  ServerSocket server = new  ServerSocket(20334);
  while(true) {
  final Socket socket = server.accept();
  new Thread() {
   public void run() {
    try {
  BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
  PrintStream ps;
  
   ps = new PrintStream(socket.getOutputStream());
  
  File dir = new File("update");
  File file = new File(dir,br.readLine());
  
  if(!file.exists()) {
   ps.println("no");
  }else {
   ps.println("yes");
  }
  
  
  int len = 0;
  BufferedInputStream bis = new BufferedInputStream(socket.getInputStream());
  BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
  
  while ((len = bis.read()) != -1)
   bos.write(len);
   
  bis.close();
  socket.close();
  } catch (IOException e) {

   e.printStackTrace();
  }
}
  }.start();
  }
}
客户端代码
public static void main(String[] args) throws UnknownHostException, IOException {

  //创建客户端
  Socket socket = new Socket("127.0.0.1",20334);
  
  //创建客户端输入输出流
  
  BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
  PrintStream ps = new PrintStream(socket.getOutputStream());
  
  System.out.println("请输入要上传文件的路径");
  //创建键盘录入对象
  Scanner scanner = new Scanner(System.in);
  //创建文件对象判断文件是否存在以及是否是文件夹
  while(true){
   File file = new File(scanner.nextLine());
   if(!file.exists()||file.isDirectory()) {
    System.out.println("你输入的路径有有误，请重新输入");
   }else {
    ps.println(scanner.nextLine());
    break;
   
   }
  }
  if("yes".equals(br.readLine())) {
   System.out.println("您上传的文件已存在，请不要重复上传");
   return;
  }
  
  BufferedInputStream bis = new BufferedInputStream(new FileInputStream(scanner.nextLine())) ;
  BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream());
  int len = 0;
  
  while((len=bis.read()) != -1)
   
   bos.write(len) ;
  bis.close();
  socket.close();
}

这代码格式都不想往下看