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();
    }
}