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
/**
* Fortune Cookie server program.
* @author Bradley Carey
* @version November 2, 2010
*/
import java.io.*;
import java.util.*;
import java.net.*;
public class FortuneServer
{
public static void main(String[] args) throws Exception
{
Scanner myScanner = new Scanner(System.in);
System.out.print("Enter port number: ");
int port = Integer.parseInt(myScanner.nextLine());
DatagramSocket socket = new DatagramSocket(port);
Random random = new Random();
while(true)
{
DatagramPacket request = new DatagramPacket(new byte[1024], 1024);
socket.receive(request);
InetAddress clientHost = request.getAddress();
int clientPort = request.getPort();
int fortuneNo = random.nextInt(10);
String fortune = "";
if(fortuneNo == 0)
fortune += "A feather in the hand is better than a bird in the air.";
else if(fortuneNo == 1)
fortune += "Better ask twice than lose yourself once.";
else if(fortuneNo == 2)
fortune += "Disbelief destroys the magic.";
else if(fortuneNo == 3)
fortune += "Fortune Not Found: Abort, Retry, Ignore?";
else if(fortuneNo == 4)
fortune += "Help! I'm being held prisoner in a chinese bakery!";
else if(fortuneNo == 5)
fortune += "Please visit us at www.wontonfood.com";
else if(fortuneNo == 6)
fortune += "Confucius says: Man who run behind car get exhausted!";
else if(fortuneNo == 7)
fortune += "Unexpected statement.";
else if(fortuneNo == 8)
fortune += "The cake IS a lie.";
else if(fortuneNo == 9)
fortune += "Cannot find host. Your fortune is void.";
else
fortune += "Error: Your fortune does not exist.";
byte[] fortunereply = fortune.getBytes();
DatagramPacket reply = new DatagramPacket(fortunereply, fortunereply.length, clientHost, clientPort);
socket.send(reply);
}
}
}