19.7 TCP 채팅 프로그램

package ch19.sec07;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.json.JSONObject;

public class ChatServer {
	// 필드
	ServerSocket serverSocket;
	ExecutorService threadPool = Executors.newFixedThreadPool(100);
	Map<String, SocketClient> chatRoom = Collections.synchronizedMap(new HashMap<>());

	// 메소드: 서버 시작
	public void start() throws IOException {
		serverSocket = new ServerSocket(50001);
		System.out.println("[서버] 시작됨");

		Thread thread = new Thread(() -> {
			try {
				while (true) {
					Socket socket = serverSocket.accept();
					SocketClient sc = new SocketClient(this, socket);
				}
			} catch (IOException e) {
			}
		});
		thread.start();
	}

	// 메소드: 클라이언트 연결 시 SocketClient 생성 및 추가
	public void addSocketClient(SocketClient socketClient) {
		String key = socketClient.chatName + "@" + socketClient.clientIp;
		chatRoom.put(key, socketClient);
		System.out.println("입장: " + key);
		System.out.println("현재 채팅자 수: " + chatRoom.size() + "\n");
	}

	// 메소드: 클라이언트 연결 종료 시 SocketClient 제거
	public void removeSocketClient(SocketClient socketClient) {
		String key = socketClient.chatName + "@" + socketClient.clientIp;
		chatRoom.remove(key);
		System.out.println("나감: " + key);
		System.out.println("현재 채팅자 수: " + chatRoom.size() + "\n");
	}

	// 메소드: 모든 클라이언트에게 메시지 보냄
	public void sendToAll(SocketClient sender, String message) {
		JSONObject root = new JSONObject();
		root.put("clientIp", sender.clientIp);
		root.put("chatName", sender.chatName);
		root.put("message", message);
		String json = root.toString();

		Collection<SocketClient> socketClients = chatRoom.values();
		for (SocketClient sc : socketClients) {
			if (sc == sender) continue;
			sc.send(json);
		}
	}

	// 메소드: 서버 종료
	public void stop() {
		try {
			serverSocket.close();
			threadPool.shutdownNow();
			chatRoom.values().stream().forEach(sc -> sc.close());
			System.out.println("[서버] 종료됨");
		} catch (IOException e1) {}
	}

	// 메소드: 메인
	public static void main(String[] args) {
		try {
			ChatServer chatServer = new ChatServer();
			chatServer.start();

			System.out.println("--------------------------------------------------------------------");
			System.out.println("서버를 종료하려면 q를 입력하고 Enter 키를 입력하세요.");
			System.out.println("--------------------------------------------------------------------");

			Scanner scanner = new Scanner(System.in);
			while (true) {
				String key = scanner.nextLine();
				if (key.equals("q")) break;
			}
			scanner.close();
			chatServer.stop();
		} catch (IOException e) {
			System.out.println("[서버] " + e.getMessage());
		}
	}
}

package ch19.sec07;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;

import org.json.JSONObject;

public class SocketClient {
	// 필드
	ChatServer chatServer;
	Socket socket;
	DataInputStream dis;
	DataOutputStream dos;
	String clientIp;
	String chatName;

	// 생성자
	public SocketClient(ChatServer chatServer, Socket socket) {
		try {
			this.chatServer = chatServer;
			this.socket = socket;
			this.dis = new DataInputStream(socket.getInputStream());
			this.dos = new DataOutputStream(socket.getOutputStream());
			InetSocketAddress isa = (InetSocketAddress) socket.getRemoteSocketAddress();
			this.clientIp = isa.getHostName();
			receive();
		} catch (IOException e) {
		}
	}

	// 메소드: JSON 받기
	public void receive() {
		chatServer.threadPool.execute(() -> {
			try {
				while (true) {
					String receiveJson = dis.readUTF();

					JSONObject jsonObject = new JSONObject(receiveJson);
					String command = jsonObject.getString("command");

					switch (command) {
						case "incoming":
							this.chatName = jsonObject.getString("data");
							chatServer.sendToAll(this, "들어오셨습니다.");
							chatServer.addSocketClient(this);
							break;
						case "message":
							String message = jsonObject.getString("data");
							chatServer.sendToAll(this, message);
							break;
					}
				}
			} catch (IOException e) {
				chatServer.sendToAll(this, "나가셨습니다.");
				chatServer.removeSocketClient(this);
			}
		});
	}

	// 메소드: JSON 보내기
	public void send(String json) {
		try {
			dos.writeUTF(json);
			dos.flush();
		} catch (IOException e) {
		}
	}

	// 메소드: 연결 종료
	public void close() {
		try {
			socket.close();
		} catch (Exception e) {}
	}
}

package ch19.sec07;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.util.Scanner;

import org.json.JSONObject;

public class ChatClient {
	// 필드
	Socket socket;
	DataInputStream dis;
	DataOutputStream dos;
	String chatName;

	// 메소드: 서버 연결
	public void connect() throws IOException {
		socket = new Socket("localhost", 50001);
		dis = new DataInputStream(socket.getInputStream());
		dos = new DataOutputStream(socket.getOutputStream());
		System.out.println("[클라이언트] 서버에 연결됨");
	}

	// 메소드: JSON 받기
	public void receive() {
		Thread thread = new Thread(() -> {
			try {
				while (true) {
					String json = dis.readUTF();
					JSONObject root = new JSONObject(json);
					String clientIp = root.getString("clientIp");
					String chatName = root.getString("chatName");
					String message = root.getString("message");
					System.out.println("<" + chatName + "@" + clientIp + "> " + message);
				}
			} catch (Exception e1) {
				System.out.println("[클라이언트] 서버 연결 끊김");
				System.exit(0);
			}
		});
		thread.start();
	}

	// 메소드: JSON 보내기
	public void send(String json) throws IOException {
		dos.writeUTF(json);
		dos.flush();
	}

	// 메소드: 서버 연결 종료
	public void unconnect() throws IOException {
		socket.close();
	}

	// 메소드: 메인
	public static void main(String[] args) {
		try {
			ChatClient chatClient = new ChatClient();
			chatClient.connect();

			Scanner scanner = new Scanner(System.in);
			System.out.println("대화명 입력: ");
			chatClient.chatName = scanner.nextLine();

			JSONObject jsonObject = new JSONObject();
			jsonObject.put("command", "incoming");
			jsonObject.put("data", chatClient.chatName);
			String json = jsonObject.toString();
			chatClient.send(json);

			chatClient.receive();

			System.out.println("--------------------------------------------------------------------");
			System.out.println("보낼 메시지를 입력하고 Enter");
			System.out.println("채팅를 종료하려면 q를 입력하고 Enter");
			System.out.println("--------------------------------------------------------------------");

			while (true) {
				String message = scanner.nextLine();
				if (message.toLowerCase().equals("q")) {
					break;
				} else {
					jsonObject = new JSONObject();
					jsonObject.put("command", "message");
					jsonObject.put("data", message);
					json = jsonObject.toString();
					chatClient.send(json);
				}
			}
			scanner.close();
			chatClient.unconnect();
		} catch (IOException e) {
			System.out.println("[클라이언트] 서버 연결 안됨");
		}
	}
}