SOCKET_여러 사람의 채 팅 을 간단하게 실현 하 다.

package com.kk.review;

import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

class Server extends Thread{
    static List<Socket> online=new ArrayList<Socket>(10); 
    private Socket socket;
    public Server(Socket socket) {
        this.socket=socket;
    }
    
    public static void main(String[] args) {
        Server.receive();
    }
    
    static void receive(){
        try{
            ServerSocket server=new ServerSocket(1234);
            for (;;) {
                Socket socket=server.accept();
                new Server(socket).start();
            }
        }catch(IOException ioe){
            ioe.printStackTrace();
        }
    }
    
    @Override
    public void run() {
        while(true){
            try{
                online.add(socket);
                InputStream in=socket.getInputStream();
                byte []buf=new byte[1024];
                int len=in.read(buf);
                String str=new String(buf,0,len);
                for(Socket client:online){
                    client.getOutputStream().write(str.getBytes());
                }
            }catch(IOException ioe){
                ioe.printStackTrace();
            }
        }
    }
}

package com.kk.review;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;

class Client extends Thread{
    
    public static void main(String[] args) {
        Client.send();
    }
    
    static void send(){
        try{
            Socket client=new Socket(InetAddress.getByName(null),1234);
            OutputStream out=client.getOutputStream();
            new Client().start();
//            Scanner input=new Scanner(System.in);
            while(true){
                Thread.sleep(500);
                BufferedReader bis=new BufferedReader(new InputStreamReader(System.in));
                String str=bis.readLine();
                out.write(str.getBytes());
            }
        }catch(IOException ioe){
            ioe.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    
    public void run() {
        try{
            Socket client=new Socket(InetAddress.getByName(null),1234);
            InputStream in=client.getInputStream();
            for (;;) {
                byte []buf=new byte[1024];
                int len=in.read(buf);
                String str=new String(buf,0,len);
                System.out.println("from server:".concat(str));
            }
        }
        catch(IOException ioe)
        {
            ioe.printStackTrace();
        }
    }
}