Socket 群聊功能

1、Server端：

　　拥有一个存放与客户端连接对象的List<socket> 有一个客户端发信息后 遍历List 实现群发功能 代码如下：

　　

 package com.socket;

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

 public class MyServer {

     public static void main(String[] args) throws Exception {
         ServerSocket ss = new ServerSocket(10002);
         List<Socket> allClient = new ArrayList<>();
         System.out.println("server　is starting....");
         while(true){
             Socket s = ss.accept();
             allClient.add(s);
             new Thread(new ServerThread(s, allClient)).start();
         }
     }

 }
 class ServerThread implements Runnable{
     private Socket s;
     private List<Socket> allClient;

     public ServerThread(Socket s, List<Socket> allClient) {
         super();
         this.s = s;
         this.allClient = allClient;
     }

     @Override
     public void run() {
         try {
             System.out.println(s.getInetAddress().getHostAddress()+"上线了...");
             BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
             String line = null;
             while((line = in.readLine())!=null){
                 for(Socket soc:allClient){
                     //向其他客户端发信息
                     if(!soc.equals(s)){
                         PrintWriter pw = new PrintWriter(soc.getOutputStream(),true);
                         pw.println(line);
                     }
                 }
             }
         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

     }

 }

2、客户端：
　　客户端需要注意的是用户不仅可以输入，还可以随时的接受服务端发来的信息，这就要求读和写分开两个线程来操作代码如下：

　　

 package com.socket;

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

 public class Client {

     public static void main(String[] args) throws IOException, Exception {
         final Socket s = new Socket(InetAddress.getLocalHost(),10002);
         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
         PrintWriter pw = new PrintWriter(s.getOutputStream(),true);
         String line = null;
         new Thread(new Runnable() {
             @Override
             public void run() {
                 try {
                     BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));
                     String str = null;
                     while((str = br.readLine())!=null){
                         System.out.println(str);
                     }
                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }
             }
         }).start();
         while ((line = br.readLine())!=null){
             pw.println(line);
         }
         s.close();
         br.close();
     }
 }