datagramclientdemo.java

java经典10例子

import java.io.*;
import java.net.*;

class DatagramClientDemo{
 	public static void main (String [] args){
 		String host = "127.0.0.1";
 		if (args.length == 1)
 			host = args [0];
   		DatagramSocket s = null;
		try{
			s = new DatagramSocket ();//创建客户端套接字
			//建立要发送的数据报以及设置服务器地址和端口
			byte [] buffer;
			buffer = new String ("Send me a datagram").getBytes ();
			InetAddress ia = InetAddress.getByName (host);
			DatagramPacket dgp=new DatagramPacket(
				buffer,buffer.length,ia,8899);
			s.send (dgp);//发送数据报
			//建立接收数据报缓冲并从服务器端接收数据
			byte [] buffer2 = new byte [100];
			dgp = new DatagramPacket (buffer2,buffer.length,ia,8899);
			s.receive (dgp);//接收从服务器端发送来的数据报
			System.out.println (new String (dgp.getData ()));
		}catch (IOException e){
			System.out.println (e.toString ());
		}finally{
			if (s != null)
				s.close (); 
		}
	}
}