Flex与服务器交互之一（URLRequest +URLLoader应用） .? 由于Flex只是一种客户端技术其本身并不能直接同数据
Flex与服务器交互之一（URLRequest +URLLoader应用） .
? 由于Flex只是一种客户端技术其本身并不能直接同数据库交互，在实际的应用开发过程中Flex提供了如URLRequest、HTTPService、RemoteObject、WebService等类以实现同服务器的通讯和数据交互，下面做一些介绍和实例解析:
?? 1、使用URLRequest向服务器发送请求，使用URLLoader接收服务器返回的数据:
??? URLRequest类可捕获单个 HTTP 请求中的所有信息，可以将 URLRequest 对象传递给 Loader、URLStream 和 URLLoader 类以及其他加载操作的 load() 方法以启动 URL 下载;默认情况下，传递给 url 参数的 URL 必须与执行调用的 SWF 文件在完全相同的域，包括子域。如果要从其它域中加载数据，请在承载数据的服务器上放置一个跨域策略文件。有关URLRequest详细可参看http://help.adobe.com/zh_CN/AIR/1.1/jslr/flash/net/URLRequest.html
?? URLVariables类主要用来在应用程序和服务器之间传输参数变量;详细查看:http://livedocs.adobe.com/flex/3_cn/langref/flash/net/URLVariables.html
?? URLLoader 类以文本、XML、二进制数据或 URL 编码变量的形式从 URL 返回请求的数据详细请参看:http://livedocs.adobe.com/flex/3_cn/langref/flash/net/URLLoader.html
??? 完成以下示例要引用到的Flex包:
import mx.rpc.events.FaultEvent; import mx.collections.XMLListCollection; import flash.net.URLLoader; import flash.net.URLRequest; import flash.net.URLVariables; import flash.net.URLRequestMethod; import flash.events.Event; import mx.utils.URLUtil; import mx.collections.ArrayCollection; import mx.rpc.events.ResultEvent; import com.adobe.serialization.json.JSON;
?? 2、应用示例一：通过URLRequest和URLVariables向服务器发送参数请求并返回服务器文本数据（以下服务器端都采用asp.net编写）
?? 服务器端代码: protected void Page_Load(object sender, EventArgs e) { //获取URLResuest请求回的参数 返回数据用；分隔以方便Flex对数据进行序列化 string rs = String.Format("name={0};age={1};address={2}",Request.QueryString["name"], Request.QueryString["age"], Request.QueryString["address"]); Response.ClearContent(); Response.ContentType = "text/plain"; Response.Write(rs); //以文本形式返回数据 Response.End(); }
?? FLEX中发送请求： private function getText():void { var v:URLVariables = new URLVariables("name=jacky&age=35&address=HongKong China"); var r:URLRequest = new URLRequest(); r.url = "http://localhost:2222/FlexService/TextFrm.aspx"; r.method = URLRequestMethod.GET; r.data = v; var l:URLLoader = new URLLoader(); l.load(r); l.addEventListener(Event.COMPLETE,txtCompleteHandler); //注册请求完成后 响应获取数据事件方法 labMsg.alpha = 1; }
?? Flex中接收返回数据 private function txtCompleteHandler(e:Event):void { var l:URLLoader = URLLoader(e.target); var o:Object = URLUtil.stringToObject(String(l.data)); //使用URLUtil对将数据进行反序列化以方便使用 txtName.text = o.name; txtAge.text = o.age; txtAddress.text = o.address; labMsg.alpha = 0; }
?? 3、应用示例二：返回JSON格式数据：
?? 服务器端代码:
???? public partial class JsonFrm : System.Web.UI.Page { Person person; protected void Page_Load(object sender, EventArgs e) { person = new Person(); person.Name = "YAO MING"; person.Age = 29; person.Address = "ShangHai China"; HttpContext.Current.Response.ClearContent(); HttpContext.Current.Response.ContentType = "text/plain"; System.Runtime.Serialization.Json.DataContractJsonSerializer dcjs = new System.Runtime.Serialization.Json.DataContractJsonSerializer(person.GetType()); dcjs.WriteObject(HttpContext.Current.Response.OutputStream,person); HttpContext.Current.Response.End(); } } [System.Runtime.Serialization.DataContract] public class Person { [System.Runtime.Serialization.DataMember] public String Name{get;set;} [System.Runtime.Serialization.DataMember] public int Age { get; set; } [System.Runtime.Serialization.DataMember] public String Address { get; set; } }
?? FLEX中发送请求：
??? private function getJson():void { var v:URLVariables = new URLVariables(); var r:URLRequest = new URLRequest(); r.url = "http://localhost:2222/FlexService/JsonFrm.aspx"; r.method = URLRequestMethod.GET; r.data = v; var l:URLLoader = new URLLoader(); l.load(r); l.addEventListener(Event.COMPLETE,jsonCompleteHandler); labMsg.alpha = 1; }
?? Flex中接收返回数据
?? public function jsonCompleteHandler(e:Event):void { var l:URLLoader = e.target as URLLoader; var o:* = JSON.decode(l.data); txtName.text = o.Name; txtAge.text = o.Age; txtAddress.text = o.Address; labMsg.alpha = 0; }
? 4、应用示例三：返回XML格式数据：
? 服务器端代码: protected void Page_Load(object sender, EventArgs e) { String s = @"<?xml version=""1.0"" encoding=""utf-8""?> <EV_ChartData_Scatter xmlns=""http://www.byd.com/ChartData/XML""> <ScatterItem id=""0""> <CAN_ITEM_ID>561</CAN_ITEM_ID> <CAN_ITEM_NAME>主控ECU通讯状况</CAN_ITEM_NAME> <ITEM_VALUE>0</ITEM_VALUE> <MATCH_VALUE>正常</MATCH_VALUE> </ScatterItem> <ScatterItem id=""1""> <CAN_ITEM_ID>561</CAN_ITEM_ID> <CAN_ITEM_NAME>主控ECU通讯状况</CAN_ITEM_NAME> <ITEM_VALUE>1</ITEM_VALUE> <MATCH_VALUE>丢包</MATCH_VALUE> </ScatterItem> </EV_ChartData_Scatter>"; Response.ClearContent(); Response.ContentType = "text/xml"; Response.Write(s); Response.End(); }
?? FLEX中发送请求：
??? private function getXML():void { var v:URLVariables = new URLVariables(); var r:URLRequest = new URLRequest(); r.url = "http://localhost:2222/FlexService/XMLFrm.aspx"; r.method = URLRequestMethod.GET; r.data = v; var l:URLLoader = new URLLoader(); l.load(r); l.addEventListener(Event.COMPLETE,xmlCompleteHandler); }
?? Flex中接收返回数据
[c-sharp] view plaincopyprint?
- [Bindable]??????????private?var?xml:XML;??
- ????????private?function?xmlCompleteHandler(e:Event):void?? ????????{??
- ????????????var?l:URLLoader?=?e.target?as?URLLoader;?? ????????????xml=?new?XML(l.data);??
- ????????????for?each(var?v?in?xml.ScatterItem)?? ????????????{??
- ?????????????????????????????}??
- ????????????labMsg.alpha?=?0;??????????}??
