一个midlet应用模型　非常经典的例子　大家可以看看　非常经典

				/*
				 * @(#)Sender.java	1.4 03/03/02
				 *
				 * Copyright (c) 2004 Sun Microsystems, Inc.  All rights reserved.
				 * Use is subject to license terms
				 */
				package example.datagram;
				
				import javax.microedition.midlet.*;
				import javax.microedition.io.*;
				import javax.microedition.lcdui.*;
				
				public class Sender extends Thread {
				
				    private DatagramConnection dc;
				    private String address;
				    private String message;
				
				    public Sender(DatagramConnection dc) {
				        this.dc = dc;
				        start();
				    }
				
				    public synchronized void send(String addr, String msg) {
				        address = addr;
				        message = msg;
				        notify();
				    }
				
				    public synchronized void run() {
				
				        while(true) {
				
				            // If no client to deal, wait until one connects
				            if (message == null) {
				                try {
				                    wait();
				                } catch (InterruptedException e) {
				                }
				            }
				
				            try {
				                byte[] bytes = message.getBytes();
				                Datagram dg = null;
				                // Are we a sender thread for the client ? If so then there's
				                // no address parameter
				                if (address == null) {
				                    dg = dc.newDatagram(bytes, bytes.length);
				                } else {
				                    dg = dc.newDatagram(bytes, bytes.length, address);
				                }
				                dc.send(dg);
				            } catch (Exception ioe) {
				                ioe.printStackTrace();
				            }
				
				            // Completed client handling, return handler to pool and
				            // mark for wait
				            message = null;
				        }
				    }
				
				}