[Java] 87. 채팅 프로그램

1. 서버

package ex20.ch04;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

// Multiflex (채팅)
public class MyServer04 {

    private List<ManagerThread> threads = new ArrayList<>();

    class ManagerThread extends Thread {
        private String username; // s1, s2, s3
        private Socket socket;
        private BufferedReader br;
        private BufferedWriter bw;


        public ManagerThread(Socket socket) {
            this.socket = socket;

            try {
                this.br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                this.bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }

        public void setUsername() {
            try {
                username = br.readLine();
                System.out.println(username + " connected");
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

        public String getUsername() {
            return username;
        }

        @Override
        public void run() {
            send("당신의 아이디를 전달해주세요");
            setUsername();
            send("당신의 아이디는 " + getUsername() + "입니다");
            while (true) {
                try {
                    String msg = br.readLine();

                    // 1. 파싱
                    String[] sps = msg.split(":"); // ALL:msg, ssar:msg
                    String protocal = sps[0];
                    String body = sps[1];

                    // 2. 프로토콜 분석
                    if (protocal.equals("ALL")) {
                        for (ManagerThread mt : threads) {
                            mt.send(body); // 전체 메시지
                        }
                    } else {
                        for (ManagerThread mt : threads) {
                            if (protocal.equals(mt.getUsername())) {
                                mt.send(body); // 귓속말
                            }
                        }
                    }


                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
        }

        public void send(String msg) {
            try {
                bw.write(msg);
                bw.write("\n");
                bw.flush();
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    public MyServer04() {
        try {
            ServerSocket serverSocket = new ServerSocket(20000);

            while (true) {
                Socket socket = serverSocket.accept();

                ManagerThread mt = new ManagerThread(socket);
                threads.add(mt);

                mt.start(); // 분신
            }


        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {
        new MyServer04();
    }
}

2. 클라이언트

package ex20.ch04;

import java.io.*;
import java.net.Socket;

public class MyClient04 {
    public static void main(String[] args) {
        try {
            Socket socket = new Socket("192.168.0.99", 20000); // 소켓 연결

            // 1. 쓰기 분신
            BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));

            new Thread(() -> {
                while (true) {
                    try {
                        String reqBody = keyboard.readLine();
                        bw.write(reqBody);
                        bw.write("\n");
                        bw.flush();
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }
                }
            }).start();

            // 2. 읽기 분신
            BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            new Thread(() -> {
                while (true) {
                    try {
                        String reqBody = br.readLine();
                        System.out.println("서버로 부터 받은 메시지 : " + reqBody);
                    } catch (IOException e) {
                        throw new RuntimeException(e);
                    }
                }
            }).start();

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}