채팅 프로그램 만들어보기

ChatThread

package com.example.chat2;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class ChatThread extends Thread{
    private String name;
    private BufferedReader br;
    private PrintWriter pw;
    private Socket socket;
    List<ChatThread> list;
    public ChatThread(Socket socket, List<ChatThread> list) throws Exception{
        this.socket = socket;
        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter pw = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
        this.br = br;
        this.pw = pw;
        this.name = br.readLine();
        this.list = list;
        this.list.add(this);
    }

    public void sendMessage(String msg){
        pw.println(msg);
        pw.flush();
    }

    @Override
    public void run() {
        // broadcast
        // ChatThread는 사용자가 보낸 메시지를 읽어들여서
        // 접속된 모든 클라이언트에게 메시지를 보낸다.

        // 나를 제외한 모든 사용자에게 "00님이 연결되었습니다."
        // 현재 ChatThread를 제외하고 보낸다.
        broadcast(name + "님이 입장하였습니다.", false);

        String line = null;
        try {
            while ((line = br.readLine()) != null){
                // 나를 포함한 ChatThread에게 메시지를 보낸다.
                if ("/quit".equals(line)){
                    break;
                }
                broadcast(name + "> " + line,true);
            }
        }catch (Exception e){ // ChatThread가 연결이 끊어졌다.
            e.printStackTrace();
        }finally {
            broadcast(name +"님이 퇴장하였습니다.", false);
            this.list.remove(this);
            try {
                br.close();
            }catch (Exception ex){

            }
            try {
                pw.close();
            }catch (Exception ex){

            }
            try {
                socket.close();
            }catch (Exception ex){

            }
        }
    }

    private void broadcast(String msg, boolean includeMe){
        List<ChatThread> chatThreads = new ArrayList<>();
        for (int i = 0; i < this.list.size(); i++){
            chatThreads.add(list.get(i));
        }

        try {
            for (int i = 0; i < chatThreads.size(); i++){
                ChatThread ct = chatThreads.get(i);
                if(!includeMe){ // 나를 포함하지 마라
                    if (ct == this){
                        continue;
                    }
                }
                ct.sendMessage(msg);
            }
        }catch (Exception ex){

        }
    }
}

ChatClient

package com.example.chat2;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;

public class ChatClient {
    public static void main(String[] args) throws Exception {
        if (args.length != 1) {
            System.out.println("사용법 : java com.example.chat2.ChatClient 닉네임");
            return;
        }

        String name = args[0];
        Socket socket = new Socket("127.0.0.1", 8090);
        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter pw = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
        BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));

        //닉네임 전송
        pw.println(name);
        pw.flush();

        // 백그라운드로 서버가 보내준 메시지를 읽어들여서 화면에 출력한다.
        InputThread inputThread = new InputThread(br);
        inputThread.start();

        // 클라이언트는 읽어들인 메시지를 서버에게 전송한다.
        try {
            String line = null;
            while ((line = keyboard.readLine()) != null) {
                if ("/quit".equals(line)) {
                    pw.println("/quit");
                    pw.flush();
                    break; //while문을 빠져나간다
                }
                pw.println(line);
                pw.flush();
            }
        } catch (Exception ex) {
            System.out.println("....");
        }
        try {
            br.close();
        }catch (Exception ex){

        }
        try {
            pw.close();
        }catch (Exception ex){

        }
        try {
            System.out.println("socket close");
            socket.close();
        }catch (Exception ex){

        }

    }

    static class InputThread extends Thread{
        BufferedReader br;

        public InputThread(BufferedReader br) {
            this.br = br;
        }

        @Override
        public void run() {
            try {
                String line = null;
                while ((line = br.readLine()) != null) {
                    System.out.println(line);
                }
            } catch (Exception ex) {
                System.out.println("....");
            }
        }
    }
}

ChatServer

package com.example.chat2;

import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class ChatServer {
    public static void main(String[] args) throws Exception{
        ServerSocket serverSocket = new ServerSocket(8090);

        List<ChatThread> list = Collections.synchronizedList(new ArrayList<>());
        while (true){
            Socket socket = serverSocket.accept(); // 클라이언트가 접속한다.
            ChatThread chatThread = new ChatThread(socket, list);
            chatThread.start();
        } // while

    } // main
}