javaのTCPとUDPプログラミングについて簡単に話します。

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class MyClient {

  public static void main(String[] args) throws Exception{
    
    Socket socket = null;
    BufferedReader in = null;
    PrintWriter out = null;
    
    BufferedReader input = null;
    //     ip        
    socket = new Socket("127.0.0.1",3333);
    
    while(true){

      in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      
      out = new PrintWriter(socket.getOutputStream(), true);
      //         
      input = new BufferedReader(new InputStreamReader(System.in));
      // out.println("this is client info!");
      String info = input.readLine();
      
      out.println(info);
      
      String str = in.readLine();
      
      System.out.println("     --》      ：" + str);
    }
    //in.close();
    //out.close();
  }

}

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class MyServices {

  public static void main(String[] args) throws Exception{
    ServerSocket ss = null;
    Socket socket = null;
    BufferedReader in = null;
    PrintWriter out = null;
    BufferedReader input = null;
    
    //   3333  
    ss = new ServerSocket(3333);
    //           
    socket = ss.accept();
    while(true){
      //           
      in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      //           
      String str = in.readLine();
      
      input = new BufferedReader(new InputStreamReader(System.in));
      
      System.out.println("     -->       ：" + str);
      
      out = new PrintWriter(socket.getOutputStream(),true);
      //          
      // out.println("hehe");
      String info = input.readLine();
      
      out.println(info);
    }
//    in.close();
//    out.flush();
//    out.close();
  }

}

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class UDPClient {

  public static void main(String[] args) throws Exception {
    
    DatagramSocket ds = null;
    DatagramPacket dp = null;
    byte[] buf = new byte[1024];
    
    ds = new DatagramSocket(3333);
    dp = new DatagramPacket(buf, 1024);
    
    //     ，     
    ds.receive(dp);
    //          
    String info = new String(dp.getData(),0, dp.getLength());
    System.out.println("       ：" + info);
  }

}

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class UDPServer {

  public static void main(String[] args) throws Exception {
    DatagramSocket ds = null;
    DatagramPacket dp = null;
    
    //       
    ds = new DatagramSocket();
    //      -->     
    String info = "hello world!";
    
    dp = new DatagramPacket(info.getBytes(), info.length(), InetAddress.getByName("localhost"),3333);
    
    //      
    ds.send(dp);
    
  }

}