Java - Network, MultiChat

import java.io.IOException;

import java.net.Socket;

public class MultiClient {

    public static void main(String[] args) throws IOException {

        

        Socket socket = null;

        // 1. 소켓 생성 + 2. 연결 요청

        try {

            socket = new Socket("127.0.0.1", 9000);

            // 3. 할일 하기 + 스레드 생성 및 실행

            System.out.println("연결 수락");

            ClientSender sender = new ClientSender(socket);

            ClientReceiver receiver = new ClientReceiver(socket);

            sender.start();

            receiver.start();

        } catch (Exception e) {

            e.printStackTrace();

            socket.close(); // 문제 발생시 소켓 종료

        }

        

    }

}

import java.io.DataOutputStream;

import java.io.IOException;

import java.net.Socket;

import java.util.Scanner;

public class ClientSender extends Thread {

    

        Socket socket;

        DataOutputStream out;

        

        public ClientSender(Socket socket) {

            this.socket = socket;

            try {

                out = new DataOutputStream(socket.getOutputStream());

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

        

        @Override

        public void run() {

            while(out != null) {

                try {

                    System.out.println("당신 -> ");

                    Scanner scan = new Scanner(System.in);

                    out.writeUTF(scan.nextLine());

                } catch(IOException e){

                    e.printStackTrace();

                    break;

                }

                

            }

        }

}

import java.io.DataInputStream;

import java.io.IOException;

import java.net.Socket;

public class ClientReceiver extends Thread {

    

    Socket socket;

    DataInputStream in;

    

    public ClientReceiver(Socket socket) {

        this.socket = socket;

        try {

            // 소켓에서 뽑고 넣기

            in = new DataInputStream(socket.getInputStream());

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    @Override

    public void run() {

        while(in != null) {

            try {

                // 받아온 내용을 출력

                System.out.println(in.readUTF());

            } catch (IOException e) {

                e.printStackTrace();

                break; // 문제가 생겼을때 종료

            }

        }

    }   

}

import java.net.ServerSocket;

import java.net.Socket;

import java.util.ArrayList;

public class MultiServer {

    static ArrayList<Socket> list = new ArrayList<Socket>();

    

    public static void main(String[] args) {

        

        

        try {

            // 1. 소켓생성 + 특정 IP 오픈

            ServerSocket server = new ServerSocket(9000);

            Socket socket;

            // 2. 연결수락(소켓)

            while(true) {

                System.out.println("요청 대기 중");

                socket = server.accept();

                // 3. 생성된 소켓 저장

                list.add(socket);

                // 4. 서버 스레드 생성

                ServerManager manager = new ServerManager(socket);

                manager.start();

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

        

    }

    

}

import java.io.DataInputStream;

import java.io.DataOutputStream;

import java.io.IOException;

import java.net.Socket;

public class ServerManager extends Thread {

    Socket socket;

    DataInputStream in;

    DataOutputStream out;

    

    public ServerManager(Socket socket) {

        this.socket = socket;

        try {

            in = new DataInputStream(socket.getInputStream());

            sendMsg(socket.getPort()+" 님이 입장 했습니다.");

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    

    @Override

    public void run() {

        try {

            while( in != null) {

                sendMsg(socket.getPort()+" -> "+in.readUTF());

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    

    // 전체 메세지

    public void sendMsg(String msg) throws IOException {

        System.out.println(msg);

        // 1. 소켓을 뽑아오고

        for(Socket s : MultiServer.list) {

            // 2. 스트림을 뽑아오고

            out = new DataOutputStream(s.getOutputStream());

            out.writeUTF(msg); // 3. 메세지 전송

            out.flush();

        }

    }

    

}