Flex与Java通信之HttpService方式

Flex用RemoteObject方式与Java通信是最常用的方式，这是一种最直观的方式。当然Flex也可以用HttpService与服务器类如servlet通信，这也是本次学习的重点。

这次学习是在上节的基础上进行的。本节学习用到的LoginEvent.as,LoginModule.sa文件代码如上节所示。

好了，新建一个servlet类LoginServlet.java，代码如下所示：

package  com.it161.servlet;
import  java.io.IOException;
import  java.io.PrintWriter;

import  javax.servlet.ServletException;
import  javax.servlet.http.HttpServlet;
import  javax.servlet.http.HttpServletRequest;
import  javax.servlet.http.HttpServletResponse;

publicclass LoginServlet  extends  HttpServlet {
    @Override
    protectedvoid service(HttpServletRequest req, HttpServletResponse resp)
           throws  ServletException, IOException {
       // TODO Auto-generatedmethod stub
       req.setCharacterEncoding( "utf-8" );
       resp.setCharacterEncoding( "utf-8" );
       PrintWriter out=resp.getWriter();
       String username=req.getParameter( "username" );
       String passworld=req.getParameter( "passworld" );
       //System.out.println(username+":"+passworld);
       if (username.equals( "admin" )&&passworld.equals( "123" )){
           out.print( true );
       } else {
           out.print( false );
       }
    }
}

 

这个servlet在web.xml中的配置如下所示：

<servlet>
     <servlet-name>LoginServlet</servlet-name>
     <servlet- class >com.yqsn.servlet.LoginServlet</servlet- class >
    </servlet>
<servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>

将MyEclipse切换到flash视图，新建一个application文件HttpServiceDemo.mxml，代码如下所示：

<? xmlversion = "1.0"  encoding = "utf-8" ?>
< s:Application  xmlns:fx = "http://ns.adobe.com/mxml/2009"
              xmlns:s = "library://ns.adobe.com/flex/spark"
              xmlns:mx = "library://ns.adobe.com/flex/mx"  minWidth = "955"  minHeight = "600" >

    < fx:Script >
       <![CDATA[
           import com.flex.ases.LoginEvent;
           import com.flex.ases.LoginMess;
           import com.flex.module.LoginModule;

           import mx.controls.Alert;
           import mx.managers.PopUpManager;
           import mx.rpc.events.FaultEvent;
           import mx.rpc.events.ResultEvent;
           privatevar loginModule:LoginModule=new LoginModule();
           [Bindable]
           private var username:String;
           [Bindable]
           private varpassworld:String;
           protectedfunction login_clickHandler(event:MouseEvent):void
           {
              // TODOAuto-generated method stub
               PopUpManager.addPopUp(loginModule,this,true);
               PopUpManager.centerPopUp(this.loginModule);
               loginModule.addEventListener(LoginEvent.LOGIN_EVENT,loginHander);
           }
           publicfunction loginHander(event:LoginEvent):void{
              //varobj:Object=event.loginMess as Object;
              username=event.loginMess['username'];
              passworld=event.loginMess['passworld'];
              httpServiceSend.send();
           }

           protectedfunction httpServiceSend_faultHandler(event:FaultEvent):void
           {
              // TODOAuto-generated method stub
              Alert.show(event.fault.message as String,"提示");

           }

           protectedfunction httpServiceSend_resultHandler(event:ResultEvent):void
           {
              // TODOAuto-generated method stub
              var result:Boolean=event.result as Boolean;
              if(result==true){
                  Alert.show(username+",欢迎您回来！","提示");
                  aaa.text=username+",欢迎您回来！";
                  login.label="";
                  bbb.text="";

              }else{
                  Alert.show("对不起，用户名或密码不存在！","提示");
              }
              //Alert.show("成功了！");
           }

       ]]>
    </ fx:Script >

    < fx:Declarations >
       <!-- Place non-visualelements (e.g., services, value objects) here -->
       < s:HTTPService  id = "httpServiceSend"   url = "http://localhost:8000/JavaAndFlexDemo/LoginServlet"  useProxy = "false" fault = "httpServiceSend_faultHandler(event)" result = "httpServiceSend_resultHandler(event)"  >
           < s:request >
              < username >{username}</ username >
              < passworld >{passworld}</ passworld >
           </ s:request >
       </ s:HTTPService >
    </ fx:Declarations >
    < s:Label  x = "200"  y = "150"  width = "182"  height = "27"  fontSize = "18"  id = "aaa"  text = "您还没有登陆，现在就"  verticalAlign = "middle" />
    < mx:LinkButton  x = "393"   y = "150"  width = "57"   height = "27"  label = "登陆"  id = "login"  fontSize = "18" click = "login_clickHandler(event)" />
    < s:Label  x = "459"  y = "150"  width = "37"  height = "27"  id = "bbb"  fontSize = "18"  text = "吧！"  verticalAlign = "middle" />
</ s:Application >

从代码中我们可以看出，我们先定义一个HttpServlet发送请求httpServiceSend，然后通过下面这种方式存值：

< s:request  >
              < username >{username}</ username >
              < passworld >{passworld}</ passworld >
           </ s:request >

这种方式很简单，我们在后台通过request. getParameter(“参数名”)取值就可以了，当然我们也可以在loginHander(event:LoginEvent)函数中通过下面方式存值并发送请求：

public  functionloginHander(event:LoginEvent): void {
              //varobj:Object=event.loginMess as Object;
              username=event.loginMess[ 'username' ];
              passworld=event.loginMess[ 'passworld' ];
              var  obj: Object = new  Object ;
              obj.username=username;
              obj.passworld=passworld;
              httpServiceSend.send(obj);
           }

运行结果是一样的，你可以试试。

好了，程序算是完成了，现在开始验收结果。

打开服务器并部署项目，运行felx页面RemoteObjectDemo.mxml，如下所示：

当我们点击“登陆”按钮后，弹出module页面，如下所示：

当我们输入的用户名和密码都正确时则提示你登陆正确：

输入错误则提示你输入不正确：

可以看出，我们输入的用户名与密码已经用httpservice方式发送到后台并且成功接受了并将结果返回给前台了。

好了，就学习这么多，下节将学习WebService方式。

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