udpserver.java

疯狂Java讲义_源码(含Java设计模式CHM

import java.awt.*;
import java.net.*;
import java.io.*;
import java.util.*;

/**
 * Description:
 * <br/>Copyright (C), 2008-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class UdpServer
{
	public static final int PORT = 30000;
	//定义每个数据报的最大大小为4K
	private static final int DATA_LEN = 4096;
	//定义该服务器使用的DatagramSocket
	private DatagramSocket socket = null;
	//定义接收网络数据的字节数组
	byte[] inBuff = new byte[DATA_LEN];
	//以指定字节数组创建准备接受数据的DatagramPacket对象
	private DatagramPacket inPacket = 
		new DatagramPacket(inBuff , inBuff.length);
	//定义一个用于发送的DatagramPacket对象
	private DatagramPacket outPacket;
	//定义一个字符串数组，服务器发送该数组的的元素
	String[] books = new String[]
	{
		"轻量级J2EE企业应用实战",
		"基于J2EE的Ajax宝典",
		"Struts2权威指南",
		"ROR敏捷开发最佳实践"
	};
	public void init()throws IOException
	{
		try
		{
			//创建DatagramSocket对象
			socket = new DatagramSocket(PORT);
			//采用循环接受数据
			for (int i = 0; i < 1000 ; i++ )
			{
				//读取Socket中的数据，读到的数据放在inPacket所封装的字节数组里。
				socket.receive(inPacket);
				//判断inPacket.getData()和inBuff是否是同一个数组
				System.out.println(inBuff == inPacket.getData());
				//将接收到的内容转成字符串后输出
				System.out.println(new String(inBuff ,
					0 , inPacket.getLength()));
				//从字符串数组中取出一个元素作为发送的数据
				byte[] sendData = books[i % 4].getBytes();
				//以指定字节数组作为发送数据、以刚接受到的DatagramPacket的
				//源SocketAddress作为目标SocketAddress创建DatagramPacket。
				outPacket = new DatagramPacket(sendData ,
					sendData.length , inPacket.getSocketAddress());
				//发送数据
				socket.send(outPacket);	
			}
		}
		//使用finally块保证关闭资源
		finally
		{
			if (socket != null)
			{
				socket.close();
			}
		}
	}
	public static void main(String[] args) 
		throws IOException
	{
		new UdpServer().init();
	}
}