quoteudpserver.java

高等院校计算机应用技术硕士研究生课程,高级计算机网络程序设计实例子代码,multicast部分.包括server , client.

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

public class QuoteUDPServer
{
	
	private static BufferedReader in;
	public static void main(String args[])
    	{
        	DatagramSocket socket = null;
	        DatagramPacket packet = null;
	        
	        boolean moreQuotes = true;
	        
        	System.out.println("QuoteUDPServer started... ");
        	try
        	{
        		//实例化一个数据报socket
        		socket = new DatagramSocket(1111);
        		in = new BufferedReader(new FileReader("one-liners.txt"));	
        	}
        	catch (FileNotFoundException e)
        	{
        		System.err.println("Couldn't open  file.");
    		}
        	catch(IOException e)
        	{
            		System.err.println(e.getMessage());
        	}
        	
        	while (moreQuotes) 
        	{
            		try 
            		{
                		byte[] buf = new byte[256];

                    		// 生成一个数据报
                		packet = new DatagramPacket(buf, buf.length);
                		//接收数据报
                		socket.receive(packet);

                    		// figure out response
                		String data = null;
                		if (in == null)
                    		data = new Date().toString();
                		else
                    		data = getNextQuote();
                    		
                		buf = data.getBytes();

		    		// 得到接收的数据报的地址
                		InetAddress address = packet.getAddress();
                		System.out.println(address.getHostAddress());
                		 
                		//得到接收数据报的端口
                		int port = packet.getPort();
                		//生成一个数据报
                		packet = new DatagramPacket(buf, data.length(), address, port);
                		//发送数据报
                		socket.send(packet);
            		}
            		catch (IOException e) 
            		{
                		e.printStackTrace();
				moreQuotes = false;
            		}
        	}
        	socket.close();

	}
	
	protected static String getNextQuote() 
	{
        	String returnValue = null;
        	try 
        	{
            		if ((returnValue = in.readLine()) == null) 
            		{
                		in.close();
                		returnValue = "No more quotes. Goodbye.";
            		}
        	} 
        	catch (IOException e) 
        	{
            		returnValue = "IOException occurred in server.";
        	}
        	return returnValue;
    	}
	
        
}