Java Socket实战之二：多线程通信

转自：http://developer.51cto.com/art/201202/317544.htm

上一篇文章说到怎样写一个最简单的Java Socket通信，但是在上一篇文章中的例子有一个问题就是Server只能接受一个Client请求，当第一个Client连接后就占据了这个位置，后续Client不能再继续连接，所以需要做些改动，当Server没接受到一个Client连接请求之后，都把处理流程放到一个独立的线程里去运行，然后等待下一个Client连接请求，这样就不会阻塞Server端接收请求了。每个独立运行的程序在使用完Socket对象之后要将其关闭。

 package com.googlecode.garbagecan.test.socket.sample2;  

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.PrintWriter;
 import java.net.ServerSocket;
 import java.net.Socket;  

 public class MyServer {
     public static void main(String[] args) throws IOException {
         ServerSocket server = new ServerSocket(10000);  

         while (true) {
             Socket socket = server.accept();
             invoke(socket);
         }
     }  

     private static void invoke(final Socket client) throws IOException {
         new Thread(new Runnable() {
             public void run() {
                 BufferedReader in = null;
                 PrintWriter out = null;
                 try {
                     in = new BufferedReader(new InputStreamReader(client.getInputStream()));
                     out = new PrintWriter(client.getOutputStream());  

                     while (true) {
                         String msg = in.readLine();
                         System.out.println(msg);
                         out.println("Server received " + msg);
                         out.flush();
                         if (msg.equals("bye")) {
                             break;
                         }
                     }
                 } catch(IOException ex) {
                     ex.printStackTrace();
                 } finally {
                     try {
                         in.close();
                     } catch (Exception e) {}
                     try {
                         out.close();
                     } catch (Exception e) {}
                     try {
                         client.close();
                     } catch (Exception e) {}
                 }
             }
         }).start();
     }
 } 

下面是Client程序代码：

 package com.googlecode.garbagecan.test.socket.sample2;  

 import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.io.PrintWriter;
 import java.net.Socket;  

 public class MyClient {
     public static void main(String[] args) throws Exception {
         Socket socket = new Socket("localhost", 10000);
         BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
         PrintWriter out = new PrintWriter(socket.getOutputStream());
         BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));  

         while (true) {
             String msg = reader.readLine();
             out.println(msg);
             out.flush();
             if (msg.equals("bye")) {
                 break;
             }
             System.out.println(in.readLine());
         }
         socket.close();
     }
 }  

测试，首先运行MyServer类，然后运行两个MyClient类，然后分别在每个MyClient的提示符下输入字符串，就可以看到Server可以分别接收处理每个Client的请求了。