ServerSocket ss = null;

Socket socket = ss.accept();

DataOutputStream dos = new DataOutputStream(socket.getOutputStream());//向客户端发送数据的输出流

DataInputStream dis = new DataInputStream(socket.getInputStream());//收客户端发来的数据的输入流

只要接收到的dis.readUTF())值

dos.writeUTF("自动回复的值");