udpreceive.java

java入门经典教程 java入门经典教程 java入门经典教程

// 例8.3.4 UDPReceive.java
import java.net.*;
import java.io.*;
public class UDPReceive
{
	public static void main(String[] args)
	{
		DatagramSocket receive = null;
		DatagramSocket send = null;
		try 
		{
			// 创建接收数据报的套接字
			receive = new DatagramSocket(8083);
			byte[] buf = new byte[1024];

			// 创建发送数据报的套接字
			send = new DatagramSocket();
			String str = "消息已收到！";
			byte[] bytes = str.getBytes();
			int length = bytes.length;

			while (true)
			{
				// 接收数据报，并输出
				DatagramPacket rp = new DatagramPacket(buf, 1024);
				receive.receive(rp);
				String temp = new String(rp.getData(),0, rp.getLength());
				System.out.println(temp.trim());
				
				// 发送已收到消息的信息
				DatagramPacket sp = new DatagramPacket(bytes, length,InetAddress.getLocalHost(), 8082);
				send.send(sp);				
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			receive.close();
			send.close();
		}
	}
}