locateserver.java

本程序可在局域网内实现聊天、传送文件功能

package org.tuna.net.locate;

import java.io.*;
import java.net.*;
import java.nio.*;
import java.nio.charset.*;

public class LocateServer extends Thread
{
	private boolean stopCommand;
	
	public LocateServer()
	{
		stopCommand = false;
	}
	
	
	// ------ For Thread ------
	public void run()
	{
		try{
			DatagramSocket srvSocket = new DatagramSocket(DataField.LOCATE_SERVER_PORT);
			byte[] receiveData = new byte[DataField.LOCATE_INFO_LEN * 4];
			Charset cset = Charset.forName("UTF-16");
			ByteBuffer buf = cset.encode(DataField.LOCATE_RESPONSE);
			byte[] sendData = buf.array();
			//DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, 
			while(!stopCommand){
				DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
			  srvSocket.receive(receivePacket);
			  ByteBuffer buffer = ByteBuffer.wrap(receiveData, 0, receiveData.length);
			  CharBuffer cbuf = cset.decode(buffer);
			  String rcv = cbuf.toString().trim();
			  if (rcv.length() < DataField.LOCATE_INFO_LEN)
			     continue;
			  else if (rcv.substring(0, DataField.LOCATE_INFO_LEN).equals(DataField.LOCATE_REQUEST)){
			    System.out.println("New request comes from " + receivePacket.getAddress().getHostAddress() + ":" + receivePacket.getPort());
			    newRequest();
			    InetAddress clientAddr = receivePacket.getAddress();
			    int clientPort = receivePacket.getPort();
			    DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, clientAddr, clientPort);
			    srvSocket.send(sendPacket);
			  }  
		  }
		  srvSocket.close();
		}
		catch(Exception e){
			e.printStackTrace();
		}
	}
	
	
	// ------ Public Methods ------
	/**
	 * 定位成功后会调用此方法
	 */
	public void newRequest()
	{
		//System.out.println("request");
	}
		
	public void stopThread()
	{
		stopCommand = true;
	}
	
  
  // ------ For Test ------	
	public static void main(String[] args)
	{
		LocateServer ls = new LocateServer();
		ls.start();
	}
}