udptest.java

孙鑫JAVA从入门到精通配套练习程序。所有程序都实际运行过

//演示UDP传输协议网络程序编写
import java.net.*;
public class UdpTest
{
	public static void main(String[] args)
	{
		if (args.length > 0)
		{
			recv();
		}
		else
		{
			send();
		}
	}
	//接收端程序编写
	public static void recv()
	{
		try
		{
			DatagramSocket ds = new DatagramSocket(6000);
			byte[] bufRecv = new byte[100];
			DatagramPacket dp = new DatagramPacket(bufRecv, 100);
			ds.receive(dp);
			System.out.println(new String(bufRecv, 0, dp.getLength()));
			
			//给发送端返回一个信息
			String strSend = "Welcome you!";
			DatagramPacket dpSend = new DatagramPacket(strSend.getBytes(),
																								 strSend.length(),
																								 dp.getAddress(),
																								 dp.getPort());
			ds.send(dpSend);
			ds.close();
		}
		catch(Throwable ex)
		{
			ex.printStackTrace();
		}
	}
	//发送端程序编写
	public static void send()
	{
		try
		{
			DatagramSocket ds = new DatagramSocket();
			String strSend = "This is zhangshan";
			DatagramPacket dp = new DatagramPacket(strSend.getBytes(), strSend.length(),
																							InetAddress.getByName("localhost"),
																							6000);
			ds.send(dp);
			//等待接收服务器端的返回信息
			byte[] bufRecv = new byte[100];
			DatagramPacket dpRecv = new DatagramPacket(bufRecv, 100);
			ds.receive(dpRecv);
			System.out.println(new String(bufRecv, 0, dpRecv.getLength()));
			ds.close();
		}
		catch(Throwable ex)
		{
			ex.printStackTrace();
		}
	}
}