j2me结合j2ee实现用户登陆功能【转】

手机客户端代码:
LoginForm:
package com;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

/** *//**
* 用Http方式与服务器交互
*
* @author zdw
*
*/
public class LoginForm extends MIDlet implements CommandListener
{
    private Form form = null;
    private Display display = Display.getDisplay(this);;
    private Command login = null;
    private Command exit = null;
    private TextField username = null;
    private TextField password = null;
    private Alert alert = null;
    private Alert error = null;

    public LoginForm()
    {
         form = new Form("用户登录");
         display.setCurrent(form);
         login = new Command("登录", Command.SCREEN, 1);
         exit = new Command("退出", Command.EXIT, 1);
         form.addCommand(login);
         form.addCommand(exit);

         username = new TextField("用户名", "", 20, TextField.ANY);
         password = new TextField("密码", "", 20, TextField.PASSWORD);

         form.append(username);
         form.append(password);
         form.setCommandListener(this);
     }

    public void initAlertOK()
    {
         alert = new Alert("提示", "登录成功!!\r\n您的用户名为:" + username.getString()
                + "\r\n密码为:" + password.getString(), null, AlertType.INFO);
         alert.setTimeout(Alert.FOREVER);
         display.setCurrent(alert);
     }

    public void initAlertError()
    {
         error = new Alert("提示", "登录失败,用户名或密码错误", null, AlertType.ERROR);
         display.setCurrent(error);
     }

    protected void startApp() throws MIDletStateChangeException
    {

     }

    /** *//**
      * 事件处理
     */
    public void commandAction(Command cmd, Displayable dis)
    {
        // 点击退出按钮事件
        if (cmd.getCommandType() == Command.EXIT)
        {
             System.out.println("exit");
            this.notifyDestroyed();
         }
        if (cmd == login)
        {
            // 必须开启独立线程来处理Http请求,否则会造成死锁
            new Thread(new Runnable()
            {
                public void run()
                {
                    try
                    {
                         inTurnServer();
                     } catch (Exception e)
                    {
                         e.printStackTrace();
                     }
                 }
             }).start();

         }
     }

    /** *//***************************************************************************
      * 与服务器交互相关代码
     */
    public void inTurnServer()
    {
        try
        {
            // 服务器请求地址
             String url = "http://localhost:8888/LoginWeb/LoginServlet";
            // 用户输入的用户名
             String username = this.username.getString();
            // 用户输入的密码
             String password = this.password.getString();
            // 用url建立一个Http连接(安全的)
             HttpConnection conn = (HttpConnection) Connector.open(url);
            // 设置请求类型为POST
             conn.setRequestMethod(HttpConnection.POST);
            // 设置一般的请求属性
             conn.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded");
             conn.setRequestProperty("User-Agent",
                    "Profile/MIDP-1.0 Configuration/CLDC-1.0");
             conn.setRequestProperty("Content-Language", "en-US");
             conn.setRequestProperty("Accept", "application/octet-stream");
             conn.setRequestProperty("Connection", "close");

            // 要发送的数据
             String formData = "username=" + username + "&password=" + password;
            // 转换显字节流
            byte[] data = formData.getBytes();
            // 设置写入流的长度
             conn.setRequestProperty("Content-Length", Integer
                     .toString(data.length));
             OutputStream os = conn.openOutputStream();
             os.write(data);
             os.close();
            // 得到Http响应代码
            int rc = conn.getResponseCode();
            // 正常响应
            if (rc == HttpConnection.HTTP_OK)
            {
                // 构建输入流
                 DataInputStream dism = new DataInputStream(conn
                         .openInputStream());
                // 读取服务器返回的字节流
                 String result = dism.readUTF();
                 dism.close();
                // 判断
                if (result.equals("true"))
                {
                    // 显示登录成功
                    this.initAlertOK();
                 }
                if (result.equals("false"))
                {
                    // 显示登录失败
                    this.initAlertError();
                    // 将输入框置空
                    this.username.delete(0, this.username.getString().length());
                    this.password.delete(0, this.password.getString().length());
                }
             }
         } catch (IOException e)
        {
             e.printStackTrace();
         }
     }

    protected void destroyApp(boolean arg0) throws MIDletStateChangeException
    {

     }

    protected void pauseApp()
    {

     }

}