MulticastSniffer.java Source code

Introduction

Here is the source code for MulticastSniffer.java

Source

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.SocketException;
import java.net.UnknownHostException;

/**
 * Multicast Sniffer, from Elliotte Harold's book Java Network Programming, by
 * O'Reilly & Associates. Page 342, first edition.
 */

public class MulticastSniffer {
    public static void main(String[] args) {
        InetAddress ia = null;
        byte[] buffer = new byte[65535];
        DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
        int port = 0;

        // read the address from the command line
        try {
            try {
                ia = InetAddress.getByName(args[0]);
            } catch (UnknownHostException e) {
                System.err.println(e);
            }
            port = Integer.parseInt(args[1]);
        } catch (Exception e) {
            System.err.println(e);
            System.err.println("Usage: java MulticastSniffer mcast-addr port");
            System.exit(1);
        }
        System.out.println("About to join " + ia);

        try {
            MulticastSocket ms = new MulticastSocket(port);
            ms.joinGroup(ia);
            while (true) {
                System.out.println("About to receive...");
                ms.receive(dp);
                String s = new String(dp.getData(), 0, 0, dp.getLength());
                System.out.println(s);
            }
        } catch (SocketException se) {
            System.err.println(se);
        } catch (IOException ie) {
            System.err.println(ie);
        }
    }
}