Simple UDP Fortune Client/Server (Proof of Concept)

Tue, 02 Nov 2010 23:09:37 -0400

This program is a simple client/server UDP/Datagram network program. The client sends a random number which is then used to display a random fortune on the client’s screen.

#Client

/**
 * Fortune Cookie Client. Sends random number to specified host via UDP and prints reply.
 * @author Bradley Carey
 * @version November 2, 2010
 */

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

public class FortuneClient
{
    public static void main(String[] args) throws Exception
    {
        if (args.length<= 1)
        {
            System.out.println("You must specify a valid hostname and port number.");
            System.exit(0);
        }
        String hostname = args[0];
        String port = args[1];

        InetAddress destination = InetAddress.getByName(hostname);

        Random myRandom = new Random();
        int requestNo = myRandom.nextInt(10);
        String toSend = "" + requestNo;

        DatagramSocket mySocket = new DatagramSocket();
        mySocket.setSoTimeout(2000);
        byte[] os = toSend.getBytes();
        DatagramPacket sendThis = new DatagramPacket(os, os.length, destination, Integer.parseInt(port));
        mySocket.send(sendThis);

        try
        {
            DatagramPacket replyPacket = new DatagramPacket(new byte[1024], 1024);
            mySocket.receive(replyPacket);
            String recvMsg = new String(replyPacket.getData());
            recvMsg = recvMsg.replaceAll("\n","");
            System.out.println("Fortune: " + recvMsg);
        }
        catch (SocketTimeoutException e)
        {
            System.out.println("Error: Timeout!");
        }

        System.out.println(toSend);
        mySocket.close();
    }
}

#Server

UDP on bradleycarey.com

Simple UDP Fortune Client/Server (Proof of Concept)