Java | 채팅프로그램

채팅프로그램

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Iterator;

public class ChatServer {

    private HashMap<String, OutputStream> clients;

    public static void main(String[] args) {
        new ChatServer().start();
        //ChatServer cs=new ChatServer();
        //cs.start() 한것과 같다

    }

    public ChatServer(){
        clients = new HashMap<>();
    }

    public void start(){
        ServerSocket serverSocket = null;
        Socket socket = null;

        try{
            serverSocket = new ServerSocket(3579);
            System.out.println("서버가 시작되었습니다");

            while(true){
                socket = serverSocket.accept(); //클라올때까지 대기
                System.out.println("ip: "+socket.getInetAddress()+", port: " +socket.getPort() + "에서 접속했습니다");
                ServerReceiver thread = new ServerReceiver(socket);
                thread.start();
            }
        }catch(IOException e){
            e.printStackTrace();
        }

    }
    public void sendToAll(String msg){
        Iterator<String> it = clients.keySet().iterator();

        while(it.hasNext()){
            try{
                DataOutputStream out = (DataOutputStream) clients.get(it.next());
                out.writeUTF(msg);

            }catch(IOException e){
                e.printStackTrace();
            }
        }
    }


    //이너클래스
    class ServerReceiver extends Thread {
        private Socket socket;
        private DataInputStream in;
        private DataOutputStream out;

        public ServerReceiver(Socket socket){
            this.socket = socket;
            try {
                in = new DataInputStream(socket.getInputStream());
                out = new DataOutputStream(socket.getOutputStream());
            }catch(IOException e){
                e.printStackTrace();
            }
        }

        @Override
        public void run() {
            String userName = "";
            try{
                userName = in.readUTF();
                sendToAll("😁" + userName + "님이 들어오셨습니다");
                clients.put(userName, out);
                System.out.println("현재 접속자: " + clients.size());

                while(in != null ){
                    String msg = in.readUTF();
                    if(msg.contains("quit")) break;
                    sendToAll(msg);
                }

            }catch(IOException e){
                e.printStackTrace();
            }finally {
                sendToAll("😁"+userName +"님이 나가셨습니다");
                clients.remove(userName);
                System.out.println("ip: "+socket.getInetAddress()+", port: " +socket.getPort() +"에서 접속을 종료했습니다");
                System.out.println("현재 접속자: " + clients.size());
            }
        }
    }



}

import java.io.*;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;

public class ChatClient {
    public static void main(String[] args) {
        System.out.println("대화명을 입력하세요");
        Scanner sc = new Scanner(System.in);
        String userName = sc.next();

        try{
            Socket socket = new Socket("127.0.0.1",3579);
            System.out.println("서버와 연결되었습니다");

            Thread sender = new Thread(new ClientSender(socket, userName));
            Thread receiver = new Thread(new ClientReceiver(socket));
            sender.start();
            receiver.start();
        }catch(IOException e){
            e.printStackTrace();
        }
    }

    static class ClientSender extends Thread {  //이너클래스
        private Socket socket;
        private DataOutputStream out;
        private String userName;

        public ClientSender(Socket socket, String userName){
            this.socket = socket;
            try{
                out = new DataOutputStream(socket.getOutputStream());
                this.userName = userName;
            }catch(IOException e){
                e.printStackTrace();
            }
        }

        @Override
        public void run() {
            BufferedReader br = null;
            try{
                br = new BufferedReader(new InputStreamReader(System.in));
                if(out != null) out.writeUTF(userName);

                while(out!= null){
                    out.writeUTF("["+userName+"]" + br.readLine());
                    // [apple] 안녕하세요
                }
            }catch (IOException e){
                e.printStackTrace();
            }finally{
                if(br != null)try{br.close();} catch(IOException e){}
                if(out != null)try{out.close();} catch(IOException e){}
            }
        }
    }
    static class ClientReceiver extends Thread { //이너클래스
        private Socket socket;
        private DataInputStream in;

        public ClientReceiver(Socket socket){
            this.socket = socket;
            try{
                in = new DataInputStream(socket.getInputStream());
            }catch (IOException e){
                e.printStackTrace();
            }
        }

        @Override
        public void run() {
            while(in != null){
                try{
                    System.out.println(in.readUTF());
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
        }
    }

}