Flex加载文件数据流

Flex加载文件数据流

本文使用URLStream,URLRequest,Loader实现数据流的加载，文件可以是图片、SWF等。

一、Flex代码

<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Script> <!--[CDATA[ import mx.controls.Alert; import mx.rpc.soap.LoadEvent; private var serverUrl:String = "http://localhost:4051/WebSite/DownloadStreamFile.aspx"; private var stream:URLStream; private var loader:Loader; private function loadPicture(event:MouseEvent):void { var urlRequest:URLRequest = new URLRequest(); stream = new URLStream(); urlRequest.url = serverUrl + "?file=1.jpg"; stream.addEventListener(Event.COMPLETE,onUrlRequestHandler); stream.load(urlRequest); } private function onUrlRequestHandler(event:Event):void { if(stream.connected) { var b:int; var bytes:ByteArray = new ByteArray(); try { do { b = stream.readByte(); bytes.writeByte(b); } while(true); } catch(e:EOFError) {} } //创建Loader的遮罩层 // var rect:Shape = new Shape(); // rect.graphics.beginFill(0xFFFFFF); // rect.graphics.drawRect(0, 0, 1000, 1000); // rect.graphics.endFill(); loader = new Loader(); loader.addEventListener(Event.COMPLETE,onLoaderHandler) loader.loadBytes(bytes); //loader.mask = rect; loader.alpha = 1; loader.cacheAsBitmap = true; loader.rotation = 0; //此时加载的图片大小暂未找到获取方法，只好在预知图片大小的情况下将loader适当的缩放一定级别 loader.scaleX = 0.6; loader.scaleY = 0.6 //Loader 对象只能有一个子显示对象,只能选择加载到Image或SWFLoader //image.addChild(loader); mySwfLoader.addChild(loader); } private function onLoaderHandler(event:Event):void { //Loader.loadBytes()时Event.COMPLETE不起作用??!! Alert.show(loader.width.toString()); } private function setSource(event:MouseEvent):void { var str:String = "http://localhost:2286/GetFile.aspx?path=DYDZ200907&file=4.swf"; mySwfLoader.source = str; } ]]--> </mx:Script> <mx:Image x="61" y="105" id="image" width="199" height="142"/> <mx:Button x="61" y="45" label="加载图片" click="loadPicture(event)"/> <mx:Button x="436" y="45" label="加载到swfLoader" click="setSource(event)"/> <mx:Canvas x="388" y="105"> <mx:SWFLoader id="mySwfLoader" scaleContent="true"/> </mx:Canvas> </mx:Application>

二、HttpService生成文件数据流代码

 protected void Page_Load(object sender, EventArgs e) { string file = Request["file"]; if (string.IsNullOrEmpty(file)) return; string filepath = Server.MapPath("~/Download/" + file); if (File.Exists(filepath)) DownLoadStreamFile(filepath); Response.End(); } /// <summary> /// 下载文件 /// </summary> /// <param name="serverfilpath"></param> /// <param name="filename"></param> public static void ToDownload(string serverfilpath, string filename) { FileStream fileStream = new FileStream(serverfilpath, FileMode.Open); long fileSize = fileStream.Length; HttpContext.Current.Response.ContentType = "application/octet-stream"; HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + UTF_FileName(filename) + "\";"); ////attachment --- 作为附件下载 ////inline --- 在线打开 HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString()); byte[] fileBuffer = new byte[fileSize]; fileStream.Read(fileBuffer, 0, (int)fileSize); HttpContext.Current.Response.BinaryWrite(fileBuffer); fileStream.Close(); HttpContext.Current.Response.End(); } /// <summary> /// 打开文件 /// </summary> /// <param name="serverfilpath"></param> /// <param name="filename"></param> public static void ToOpen(string serverfilpath, string filename) { FileStream fileStream = new FileStream(serverfilpath, FileMode.Open); long fileSize = fileStream.Length; HttpContext.Current.Response.ContentType = "application/octet-stream"; HttpContext.Current.Response.AddHeader("Content-Disposition", "inline; filename=\"" + UTF_FileName(filename) + "\";"); HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString()); byte[] fileBuffer = new byte[fileSize]; fileStream.Read(fileBuffer, 0, (int)fileSize); HttpContext.Current.Response.BinaryWrite(fileBuffer); fileStream.Close(); HttpContext.Current.Response.End(); } private static string UTF_FileName(string filename) { return HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8); } /// <summary> /// 下载文件数据流 /// </summary> /// <param name="serverfilpath"></param> public static void DownLoadStreamFile(string serverfilpath) { int blocksize = 1024 * 100; byte[] buffer = new byte[blocksize]; byte[] fileHeader = new byte[101]; int startindex = 0; int bytesread = 0; int bytesfinish = 0; int filesize = 0; string headerText = string.Empty; BinaryReader bReader = null; bReader = new BinaryReader(File.OpenRead(serverfilpath)); filesize = Convert.ToInt32(bReader.BaseStream.Length); while (bytesfinish < filesize) { if (bytesfinish + blocksize < filesize) bytesread = bReader.Read(buffer, startindex, blocksize); else bytesread = bReader.Read(buffer, startindex, filesize - bytesfinish); bytesfinish += bytesread; HttpContext.Current.Response.OutputStream.Write(buffer, 0, bytesread); } bReader.Close(); HttpContext.Current.Response.End(); }

注：本示例加载时获取不到图片等文件的大小，显示时不精确。