写过很多文件上传的功能，包括AJAX实现动态监控上传进度的，现在看到了FLEX实现文件上传功能，还真是很方便，没什么好说的，上代码：

upload.mxml

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="init()" layout="absolute" width="497" height="136" backgroundGradientAlphas="[1.0, 1.0]" backgroundGradientColors="[#F2F8F8, #45E7E5]">
    <mx:Script source="upload.as"></mx:Script>
    <mx:Style>
        .myfont{font-size:13pt}
    </mx:Style>
    <mx:Button x="10" y="95" label="上传文件" click="pickfile()" styleName="myfont"/>
    <mx:Label x="10" y="10" text="文件上传" styleName="myfont"/>
    <mx:ProgressBar x="10" y="40" width="457" themeColor="#F20D7A" 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"/>
</mx:Application>

upload.as

 1 // ActionScript file
 2 import flash.events.Event;
 3 import flash.net.FileFilter;
 4 import flash.net.FileReference;
 5 private var fileRef:FileReference = new FileReference();
 6 private function init():void{
 7     
 8 }
 9 
10 private function pickfile():void{
11     var imageTypes:FileFilter = new FileFilter("图片 (*.jpg, *.jpeg, *.gif,*.png)", "*.jpg; *.jpeg; *.gif; *.png");
12     var textTypes:FileFilter = new FileFilter("文本文件(*.txt","*.txt;");
13     var officeType:FileFilter = new FileFilter("Office文件(*.doc, *.xls","*.doc; *.xls");
14     var anyType:FileFilter = new FileFilter("所有文件(*.*)","*.*");
15     var allTypes:Array = new Array(imageTypes, textTypes,officeType,anyType);
16     fileRef.addEventListener(Event.SELECT, selectHandler);
17     fileRef.addEventListener(Event.COMPLETE, completeHandler);
18     fileRef.addEventListener(ProgressEvent.PROGRESS, progressHandler);
19     fileRef.addEventListener("ioError", ioerrorHandler);
20     try{
21         var success:Boolean = fileRef.browse(allTypes);
22     }catch (error:Error){
23         trace("Unable to browse for files."+error.toString());
24     }
25 }
26 private function ioerrorHandler(event:Event):void{
27     trace("Unable to upload file."+event.toString());
28 }
29 private function progressHandler(event:ProgressEvent):void{
30     lbProgress.text = " 已上传 " + (event.bytesLoaded/1024).toFixed(2)+ " K，共 " + (event.bytesTotal/1024).toFixed(2) + " K";
31     var proc: uint = event.bytesLoaded / event.bytesTotal * 100;
32     progress1.setProgress(proc, 100);
33     progress1.label= "当前进度: " + " " + proc + "%";
34 
35 }
36 private    function selectHandler(event:Event):void{
37     var request:URLRequest = new URLRequest("http://localhost:9080/upload/upload.jsp")
38     try
39     {
40         fileRef.upload(request);
41     }
42     catch (error:Error)
43     {
44         trace("Unable to upload file."+error.toString());
45     }
46 }
47 private function completeHandler(event:Event):void{
48     trace("uploaded");
49 }
50 
51 

效果图：