quoteserverthread.java

这是一个英文版的《Java程序设计与问题解决》现在好多大学都当成教材

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

public class QuoteServerThread extends Thread {
    private DatagramSocket socket = null;
    private DataInputStream in = null;
    private boolean moreQuotes = true;

    public QuoteServerThread() throws IOException {
        super("QuoteServerThread");
        socket = new DatagramSocket(4445);
	try {
            in = new DataInputStream(new FileInputStream("one-liners.txt"));
	} catch (FileNotFoundException e) {
            System.err.println("Could not open quote file. Serving time instead.");
        }
    }

    public void run() {

        while (moreQuotes) {
            try {
                byte[] buf = new byte[256];

                    // receive request
                DatagramPacket packet = new DatagramPacket(buf, buf.length);
                socket.receive(packet);

		    // figure out response
                String dString = null;
                if (in == null)
                    dString = new Date().toString();
                else
                    dString = getNextQuote();
                dString.getBytes(0, dString.length(), buf, 0);

                    // send the response to the client at "address" and "port"
                InetAddress address = packet.getAddress();
                int port = packet.getPort();
                packet = new DatagramPacket(buf, buf.length, address, port);
                socket.send(packet);
            } catch (IOException e) {
                e.printStackTrace();
		moreQuotes = false;
            }
        }
	socket.close();
    }

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

}