flex 利用json读写数据

由于一直用json开发，对json比较熟悉了，所以学习flex以后一直想做一个flex与json的开发，网上海一样的资源一直没找到合适的，今天偶然间搜到一篇文章才知道flex早就支持json解析。这里提供资源下载网站 
http://code.google.com/p/as3corelib/downloads/list 。顺便将例子上传上来希望对大家学习有帮助。 
举例如下： 
步骤1：到上面的链接中下载swc文件到lib包下 
步骤2：在webRoot下新建文件夹flexds，其下新建文件json.jsp 

 json.jsp内容如下：

 <jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="1.2">
 <jsp:directive.page import="java.text.*"/>
 <jsp:directive.page import="java.lang.*"/>
 <jsp:directive.page contentType="text/json"/>
     [<jsp:scriptlet>
         <![CDATA[
             double compa = 1000.0;
             double compb = 900.0;
             for (int i = 0; i<=30; i++) {
             compa += ( Math.random() * 100 ) - 50;
             compb += ( Math.random() * 100 ) - 50;
             if ( i > 0 ) out.print( "," );
             ]]> </jsp:scriptlet>
             {"compa":<jsp:expression>compa</jsp:expression>,
             "compb":<jsp:expression>compb</jsp:expression>}<jsp:scriptlet>
             <![CDATA[ }
         ]]>
     </jsp:scriptlet>
 ]
 </jsp:root>

 步骤3：下面做测试文件flexSrc下新建jsondg.mxml文件，内容如下：
 <?xml version="1.0" encoding="utf-8"?>
 <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
                 layout="vertical"
                 creationComplete="jsonservice.send()">
     <mx:Script>
         <![CDATA[
             import mx.rpc.events.ResultEvent;
             import com.adobe.serialization.json.JSONDecoder;
             import mx.controls.Alert;

             private function onJSONResult(event:ResultEvent):void
             {
                 var data:String=event.result.toString();

                 data=data.replace(/\s/g, '');
                 var jd:JSONDecoder=new JSONDecoder(data);
                 dg.dataProvider=jd.getValue();
             }
         ]]>
     </mx:Script>
     <mx:HTTPService id="jsonservice"
                     url="http://localhost:8080/felxDOC/flexds/json.jsp"
                     resultFormat="text"
                     result="onJSONResult(event)"/>
     <mx:Panel title="Stock Data "
               width="100% "
               height="100% ">
         <mx:DataGrid id="dg"
                      width="100%"
                      height="100%">
             <mx:columns>
                 <mx:DataGridColumn dataField="compa"/>
                 <mx:DataGridColumn dataField="compb"/>
             </mx:columns>
         </mx:DataGrid>
     </mx:Panel>
 </mx:Application>