Java - Network - Chat

< Chat >

import java.io.IOException;

import java.net.InetSocketAddress;

import java.net.ServerSocket;

import java.net.Socket;

public class ChatServer {

    public static void main(String[] args) {

        

        try {

            //1. 서버소켓 생성+특정 IP 개방

            ServerSocket server = new ServerSocket(5001);       

            System.out.println("연결 요청 대기");

            //2. 연결 수락

            Socket socket = server.accept();

            System.out.println("연결 수락");

            //3. 메시지가 오면 받아서 읽고

            Receiver recv = new Receiver(socket);   

            recv.start();

            //4. 보낼 메시지가 있으면 보낸다.

            Sender sender = new Sender(socket);

            sender.start();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

import java.net.Socket;

public class ChatClient {

    public static void main(String[] args) {

        

        try {

            //1. 소켓생성+접속 요청

            Socket socket = new Socket("localhost",5001);

            //2. 보낼 메시지 보내고

            Sender sender = new Sender(socket);

            sender.start();

            //3. 받을 메시지 받고

            Receiver recv = new Receiver(socket);

            recv.start();

        } catch (Exception e) {

            e.printStackTrace();

        }

        

    }

}

< Send, Receive MSG >

import java.io.IOException;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.net.Socket;

import java.util.Scanner;

public class Sender extends Thread {

    

    private Socket socket;

    OutputStream os = null;

    OutputStreamWriter writer = null;

    Scanner scan = null;

    public Sender(Socket socket) {

        this.socket = socket;

    }

    @Override

    public void run() {

        String msg;

        try {

            //1. 스트림 준비

            os = socket.getOutputStream();

            writer = new OutputStreamWriter(os, "UTF-8");

            while(os != null) {

                scan = new Scanner(System.in);//스캐너 준비

                msg = scan.nextLine();//입력값 읽어오기

                writer.write(msg);//내보내기

                writer.flush();

            }

        }catch(Exception e) {

            try {

                writer.close();

                os.close();

            } catch (IOException e1) {}         

        }

    }

}

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.net.Socket;

public class Receiver extends Thread {

    private Socket socket;

    InputStream is = null;

    InputStreamReader reader = null;

    

    public Receiver(Socket socket) {

        this.socket = socket;

    }

    @Override

    public void run() {

        //1. 스트림 준비

        try {

            is = socket.getInputStream();

            reader = new InputStreamReader(is,"UTF-8");                     

            char[] arr = new char[100];

            while(is != null) {

                int len = reader.read(arr);

                String msg = new String(arr);

                String result = msg.substring(0,len);               

                System.out.println("상대> "+result);//3. 읽은 내용 출력

                arr = new char[100];// 긴문 장 후 짧은 문장이 올 경우 배열에 남은 값과 섞이는 것을 방지

            }

        } catch (IOException e) {

            try {

                is.close();

                reader.close();

            } catch (IOException e1) {}         

            e.printStackTrace();

        }

    }

    

}