채팅하기

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

public class MyClient {

    public MyClient() throws IOException {
        // 1. 서버 연결
        Socket socket = new Socket("", 10000);

        // 2. 버퍼 생성
        BufferedReader reader = new BufferedReader(
                new InputStreamReader(socket.getInputStream(), "utf-8")
        );
        BufferedWriter writer = new BufferedWriter(
                new OutputStreamWriter(socket.getOutputStream(), "utf-8")
        );
        Scanner keyboard = new Scanner(System.in, "utf-8");

        // 쓰기 스레드
        new Thread(() -> {
            try {
                while(true){
                    String msg = keyboard.nextLine();
                    writer.write("yhl0326:"+msg);
                    writer.write("\n");
                    writer.flush();
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }).start();

        // 읽기 스레드
        new Thread(() -> {
            try {
                while(true){
                    String msg = reader.readLine(); // 버퍼 비우기
                    System.out.println("클라이언트로 부터 받은 메세지 : "+msg);
                }

            }catch (Exception e){
                e.printStackTrace();
            }
        }).start();

    }

    public static void main(String[] args) {
        try {
            new MyClient();
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

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

public class MyServer {

    ServerSocket serverSocket;
    Socket socket;
    BufferedReader reader;
    BufferedWriter writer;
    Scanner keyboard;

    public MyServer() throws Exception {
        // 1. 메인쓰레드는 리스너를 담당
        serverSocket = new ServerSocket(10000);
        socket =  serverSocket.accept(); // 리스너 대기중
        System.out.println("클라이언트가 연결되었습니다");
        System.out.println(socket.getPort());
        System.out.println(socket.getInetAddress());

        connectLine();
        read();
        write();
    }

    public static void main(String[] args) {
        try {
            new MyServer();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


//아래로 보내버려도 무관 (중요치 않은 코드기 때문)

    private void connectLine() throws Exception{
        reader = new BufferedReader(
                new InputStreamReader(socket.getInputStream(),"utf-8")
        );
        writer = new BufferedWriter(
                new OutputStreamWriter(socket.getOutputStream(),"utf-8")
        );
        keyboard = new Scanner(System.in,"utf-8");
    }

    private void write(){
        new Thread(() -> {
            try {
                while(true){
                    String msg = keyboard.nextLine();
                    writer.write(msg);
                    writer.write("\n");
                    writer.flush();
                }

            }catch (Exception e){
                e.printStackTrace();
            }
        }).start();
    }

    private void read(){
        new Thread(() -> {
            try {
                while(true){
                    try {
                        String msg = reader.readLine(); // 버퍼 비우기
                        String username = msg.split(":")[0];
                        String body = msg.split(":")[1];
                        System.out.println(username+" : "+body);
                    }catch (Exception e){
                        System.out.println("괜찮아!!");
                    }

                }

            }catch (Exception e){
                e.printStackTrace();
            }
        }).start();
    }
}

server와 client가 채팅할수있다