（转载）Java Socket实战之二：多线程通信

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。

具体代码如下：

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。