---------------------------------------------服务端-----------------------------------------------

 1 package C;
 2 import java.io.*;
 3 import java.net.*;
 4 
 5 public class Server extends ServerSocket            
 6 {
 7     public Server(int serverPort) throws IOException
 8     {
 9         super(serverPort);
10         try
11         {
12             while (true)
13             {
14                 Socket socket = accept();
15                 new ServerThread(socket);
16             }
17         } catch (IOException e) {
18             e.printStackTrace();
19         }
20         finally {
21             close();
22         }
23     }
24     class ServerThread extends Thread       /*建立服务端线程*/
25     {
26         private Socket socket;
27         private BufferedReader in;
28         private PrintWriter out;
29         public ServerThread(Socket s) throws IOException
30         {
31             this.socket = s;
32             in = new BufferedReader(new InputStreamReader(
33                     socket.getInputStream(), "GB2312"));        /*国标码*/
34             out = new PrintWriter(socket.getOutputStream(),true);
35             start();                /*开始线程*/
36         }
37 
38         public void run()
39         {
40                     try {
41                 while (true)
42                 {
43                     String line = in.readLine();
44                     if ("finish".equals(line))
45                     {
46                         System.out.println("服务器已停止监听");
47                         break;
48                     }
49                     System.out.println("接收到的数据：" + line);
50                     String msg = "'" + line + "'已传输到服务器端.";
51                     out.println(msg);
52                     out.flush();
53                 }
54                 out.close();
55                 in.close();
56                 socket.close();
57             }
58             catch (IOException e)
59             {
60                 e.printStackTrace();
61             }
62         }
63     }
64         public static void main(String[] args) throws IOException
65         {
66             System.out.println("服务器开始运行......");
67             new Server(2333);       /*绑定端口号*/
68         }
69 
70 }
---------------------------------------------客户端-----------------------------------------------

 1 package C;
 2 import java.io.*;
 3 import java.net.*;
 4 
 5     public class Client
 6     {
 7         private Socket socket;                  /*定义socket连接*/
 8         private BufferedReader reader;          /*从字符输入流读取文本*/
 9         private PrintWriter writer;             /*打印到文本输出流*/
10 
11         public Client(int serverPort) {                 /*定义客户端端口号*/
12             try {                                                       /*抛异常*/
13                 socket = new Socket("123.206.78.55", serverPort);
14                 reader = new BufferedReader(
15                         new InputStreamReader(socket.getInputStream()));        /*标准输入输出流*/
16                 writer = new PrintWriter(socket.getOutputStream());
17 
18                 while (true)
19                 {
20 
21                     BufferedReader in = new BufferedReader(
22                             new InputStreamReader(System.in));
23                     String message = in.readLine();
24                     writer.println(message);
25                     writer.flush();                             /*不关闭流，清空输入缓存区*/
26 
27                     if ("finish".equals(message))
28                     {
29                         System.out.println("服务器已停止监听");
30                         break;
31                     }
32                     String received = reader.readLine();
33                     System.out.println(received);
34                 }
35 
36                 writer.close();
37                 reader.close();            /*关闭流*/
38                 socket.close();
39 
40             }
41             catch (UnknownHostException ex)
42             {
43                 ex.printStackTrace();
44             }
45             catch (IOException ex)
46             {
47                 ex.printStackTrace();       /*在命令行打印异常信息在程序中出错的位置及原因*/
48             }
49         }
50 
51 
52 
53         public static void main(String[] args)
54         {
55              new Client(2333);      /*绑定端口号*/
56         }
57     }

服务端是通过客户端的流式输入来实现监听和停止监听的。