java 网络编程（三）简单的即时通讯（UDP传输）

发送端：

package cn.sasa.netDemo2;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.Scanner;

public class SendDemo {

    public static void main(String[] args) throws IOException {
        /**
         *
         */
        Scanner scanner = new Scanner(System.in);
        DatagramSocket socket = new DatagramSocket();//发送使用空参构造函数
        InetAddress host = InetAddress.getByName("127.0.0.1");

        while(true) {
            String input = scanner.nextLine();
            byte[] buff = input.getBytes();
            DatagramPacket packet = new DatagramPacket(buff, buff.length, host, 8046);
            socket.send(packet);//调用send
        }
    }
}

接收端：

package cn.sasa.netDemo2;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class ReceiveDemo {

    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(8046);
        byte[] buff = new byte[1024];

        while(true) {
            DatagramPacket packet = new DatagramPacket(buff, buff.length);
            socket.receive(packet);
            int length = packet.getLength();//接收的字节长度
            System.out.println(new String(buff,0,length)+"==="+packet.getAddress().getHostAddress());
        }
    }
}