Java——UDP

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

//=================================================
// File Name       :	UDPServer_demo
//------------------------------------------------------------------------------
// Author          :	Common

//主类
//Function        : 	UDPServer_demo
public class UDPServer_demo {

	public static void main(String[] args) throws Exception{
		// TODO 自动生成的方法存根
		DatagramSocket ds = null;					//声明DatagramSocket对象
		DatagramPacket dp = null;					//声明DatagramPacket对象
		ds = new DatagramSocket(3000);
		String str = "HelloWord";
		dp = new DatagramPacket(str.getBytes(),str.length(),InetAddress.getByName("localhost"),9000);
		System.out.println("发送信息");
		ds.send(dp);
		ds.close();
	}

}

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

//=================================================
// File Name       :	UDPClient_demo
//------------------------------------------------------------------------------
// Author          :	Common

//主类
//Function        : 	UDPClient_demo
public class UDPClient_demo {

	public static void main(String[] args) throws Exception{
		// TODO 自动生成的方法存根
		DatagramSocket ds = null;					//声明DatagramSocket对象
		byte[] buf = new byte[1024];			//定义接收数据的字节数据
		DatagramPacket dp = null;					//声明DatagramPacket对象
		ds = new DatagramSocket(9000);		//此客户端在9000端口监听
		dp = new DatagramPacket(buf,1024);			//指定接收数据的长度为1024
		System.out.println("等待接收数据");
		ds.receive(dp); 				//接收数据
		String str = new String(dp.getData(),0,dp.getLength())+" from"
		+dp.getAddress().getHostAddress()+" : "+dp.getPort();	//接收数据
		System.out.println(str);			//输出数据
		ds.close();
	}

}