네트워크 - 프로그램 예제

- SocketCloseUtil

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

import static util.MyLogger.log;

public class SocketCloseUtil {

    public static void closeAll(Socket socket, InputStream input, OutputStream output) {
        close(input);
        close(output);
        close(socket);
    }

    public static void close(InputStream input) {
        if (input != null) {
            try {
                input.close();
            } catch (IOException e) {
                log(e.getMessage());
            }
        }
    }

    public static void close(OutputStream output) {
        if (output != null) {
            try {
                output.close();
            } catch (IOException e) {
                log(e.getMessage());
            }
        }
    }

    public static void close(Socket socket) {
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
                log(e.getMessage());
            }
        }
    }
}

 

 

- ClientV6

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

import static util.MyLogger.log;

public class ClientV6 {

    private static final int PORT = 12345;

    public static void main(String[] args) throws IOException {
        log("클라이언트 시작");

        try(Socket socket = new Socket("localhost", PORT);
            DataInputStream input = new DataInputStream(socket.getInputStream());
            DataOutputStream output = new DataOutputStream(socket.getOutputStream())) {

            log("소캣 연결: " + socket);

            Scanner scanner = new Scanner(System.in);
            while (true) {
                System.out.print("전송 문자: ");
                String toSend = scanner.nextLine();

                // 서버에게 문자 보내기
                output.writeUTF(toSend);
                log("client -> server: " + toSend);

                if (toSend.equals("exit")) {
                    break;
                }

                // 서버로부터 문자 받기
                String received = input.readUTF();
                log("client <- server: " + received);
            }
        } catch (IOException e) {
            log(e);
        }
    }
}

 

 

- ServerV6

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

import static util.MyLogger.log;

public class ServerV6 {

    private static final int PORT = 12345;

    public static void main(String[] args) throws IOException {
        log("서버 시작");
        SessionManagerV6 sessionManager = new SessionManagerV6();
        ServerSocket serverSocket = new ServerSocket(PORT);
        log("서버 소켓 시작 - 리스닝 포트: " + PORT);

        // ShutdownHook 등록
        ShutdownHook shutdownHook = new ShutdownHook(serverSocket, sessionManager);
        Runtime.getRuntime().addShutdownHook(new Thread(shutdownHook, "shutdown"));

        try {
            while (true) {
                Socket socket = serverSocket.accept(); // 블로킹
                log("소켓 연결: " + socket);

                SessionV6 session = new SessionV6(socket, sessionManager);
                Thread thread = new Thread(session);
                thread.start();
            }
        } catch (IOException e) {
            log("서버 소켓 종료: " + e);
        }

    }

    static class ShutdownHook implements Runnable {
        private final ServerSocket serverSocket;
        private final SessionManagerV6 sessionManager;

        public ShutdownHook(ServerSocket serverSocket, SessionManagerV6 sessionManager) {
            this.serverSocket = serverSocket;
            this.sessionManager = sessionManager;
        }

        @Override
        public void run() {
            log("shutdownHook 실행");
            try {
                sessionManager.closeAll();
                serverSocket.close();

                Thread.sleep(1000); // 자원 정리 대기
            } catch (Exception e) {
                e.printStackTrace();
                System.out.println("e = " + e);
            }

        }
    }
}

 

 

- SessionManagerV6

import java.util.ArrayList;
import java.util.List;

// 동시성 처리
public class SessionManagerV6 {

    private List<SessionV6> sessions = new ArrayList<>();

    public synchronized void add(SessionV6 session) {
        sessions.add(session);
    }

    public synchronized void remove(SessionV6 session) {
        sessions.remove(session);
    }

    public synchronized void closeAll() {
        for (SessionV6 session : sessions) {
            session.close();
        }
        sessions.clear();
    }
}

 

 

- SessionV6

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

import static network.tcp.SocketCloseUtil.*;
import static util.MyLogger.log;

public class SessionV6 implements Runnable {

    private final Socket socket;
    private final DataInputStream input;
    private final DataOutputStream output;
    private final SessionManagerV6 sessionManager;
    private boolean closed = false;

    public SessionV6(Socket socket, SessionManagerV6 sessionManager) throws IOException {
        this.socket = socket;
        this.input = new DataInputStream(socket.getInputStream());
        this.output = new DataOutputStream(socket.getOutputStream());
        this.sessionManager = sessionManager;
        this.sessionManager.add(this);
    }

    @Override
    public void run() {
        try {
            while (true) {
                // 클라이언트로부터 문자 받기
                String received = input.readUTF();
                log("client -> server: " + received);

                if (received.equals("exit")) {
                    break;
                }

                // 클라이언트에게 문자 보내기
                String toSend = received + " World!";
                output.writeUTF(toSend);
                log("client <- server: " + toSend);
            }
        } catch (IOException e) {
            log(e);
        } finally {
            sessionManager.remove(this);
            close();
        }
    }

    // 세션 종료시, 서버 종료시 동시에 호출될 수 있다.
    public synchronized void close() {
        if (closed) {
            return;
        }
        closeAll(socket, input, output); // shutdown
        closed = true;
        log("연결 종료: " + socket);
    }
}