flex 文件下载 +Tomcat web应用服务器

　　var download_request:URLRequest=new URLRequest(encodeURI(StringUtil.trim(url)));

    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" URIEncoding="UTF-8"/>

<?xml version="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 mx.controls.Alert;
			import mx.utils.StringUtil;
			protected function button1_clickHandler(event:MouseEvent):void
			{
				// TODO Auto-generated method stub
				downLoad("http://192.168.191.5:8080/netcanvas_s/","360软件小助手截图20140508200748.png");
			}
			
			private  var fileRef:FileReference=new FileReference();
			/**
			 * 文件下载
			 * backUrl: 后台服务器地址
			 * pathFileName: 下载的文件路径+文件名
			 * */
			public  function downLoad(backUrl:String,pathFileName:String):void{
				fileRef.addEventListener(Event.COMPLETE,completeHandler );
				fileRef.addEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler);
				fileRef.addEventListener(ProgressEvent.PROGRESS, progressHandler);
				fileRef.addEventListener(IOErrorEvent.IO_ERROR,ioShow);
				var fileNameArr:Array=StringUtil.trim(pathFileName).split(‘/‘);
				var decodeName=fileNameArr[fileNameArr.length-1];                                //截取文件名
				var url:String=backUrl+pathFileName;
				var download_request:URLRequest=new URLRequest(encodeURI(StringUtil.trim(url)));
				fileRef.download(download_request,decodeName);                                        //下载文件并加入默认文件名
				
			}
			//下载进入处理时间
			private  function progressHandler(event:ProgressEvent):void{
				lbProgress.text = " 已下载 " + (event.bytesLoaded/1024).toFixed(2)+ " K，共 " + (event.bytesTotal/1024).toFixed(2) + " K";
				var proc: uint = event.bytesLoaded / event.bytesTotal * 100;
				progress1.setProgress(proc, 100);
				progress1.label= "当前进度: " + " " + proc + "%";
				
			}
			
			//文件下载成功事件
			private  function completeHandler(event:Event):void {
				mx.controls.Alert.show("文件下载成功");
			}
			//I/O错误处理
			private  function ioShow(evt: IOErrorEvent){   
				Alert.show(evt.toString(),"IO错误");   
			}
			//安全沙箱问题事件
			private  function securityErrorHandler(event:SecurityErrorEvent){
				Alert.show(event.text);
			}
		
			
		]]>
	</fx:Script>
	
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
	</fx:Declarations>
	<s:Button x="289" y="149" label="下载" click="button1_clickHandler(event)"/>
	<mx:ProgressBar x="10" y="40" width="457"   minimum="0" mode="manual" maximum="100" id="progress1" label="当前进度: 0%" styleName="myfont" fontWeight="normal"/>
	<mx:Label x="146" y="98" width="321" id="lbProgress" styleName="myfont" textAlign="right"/>
</s:Application>