broadcasterserver.java

来自「java 完全探索的随书源码」· Java 代码 · 共 90 行

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

public class BroadcasterServer
{
  // Set a default listener port
  private int senderPort = 59;
  // set a 10 second UDP timeout
  private static final int TIMEOUT = 10000;
  private DatagramSocket senderSocket = null;
  private static int MAX_PACKET_SIZE = 255;

  // Default Constructor
  public BroadcasterServer()
  {
    super();
  }

  // Alternate Constructor to Override Port
  public BroadcasterServer( int newPort )
  {
    // overide port setting
    senderPort = newPort;
  }

  public void sendBroadcast( String msg )
  {
    // Determine the actual size of the message
    int msgSize = msg.length();

    // Create a byte to hold the message
    byte[] buffer = new byte[ msgSize ];
    buffer = msg.getBytes();

    try
    {
      // For this example, just send it to the local host
      InetAddress addr = InetAddress.getLocalHost();

      // Create the packet of information
      DatagramPacket infoPacket =
        new DatagramPacket( buffer, msgSize, addr, this.senderPort );

      senderSocket = new DatagramSocket();

      // Send the packet and clean up the resources
      senderSocket.send( infoPacket );
      senderSocket.close();
    }
    catch( Exception ex )
    {
      System.out.println( "Problem creating socket on port: " + senderPort );
      System.exit( -1 );
    }
  }

  public static void main( String[] args )
  {
    BroadcasterServer server = null;
    int argLength = args.length;
    // Make sure the correct number of args were passed in
    if ( argLength != 2 )
    {
      System.out.println( "Usage: java BroadcasterClient <port> <message>" );
      System.exit( 0 );
    }

    int port = 0;

    String arg = args[0];
    String msg = args[1];

    try
    {
      // Try to parse the port string into an int
      port = Integer.parseInt( arg );
    }
    catch( Exception ex )
    {
      System.out.println( "Invalid port specified on the command line:arg" );
      System.exit( -1 );
    }

    server = new BroadcasterServer( port );
    // Broadcast the data out
    server.sendBroadcast( msg );
  }
}