flex java red5_使用 Flex 和Java servlets 将文件上传到 RED5 服务器的步骤

r囧r小猫 2022-11-03 00:58 51阅读 0赞

本文使用一个 demo 来演示如何使用 Flex 和 Java servlets 上传一个任意类型的本地文件到 RED5 服务器。使用的是 Flex 的 FileReference 接口，该接口可以对远程服务器上的文件进行上传、下载。FileReference 类提供了一个对话框接口和一个 upload 方法，通过该对话框，选择本地文件，而 upload 方法将会调用远程服务器端的 PHP，ASP 或者 Java 代码来进行上传。         首先创建一个 Flex3 应用程序，该程序获得本地文件，并调用 RED5 服务器 "http://localhost:5080/Red5FileUploadProj/fileupload" 的 servlet。

UploadToRed5Proj.mxml 源代码如下：

\[Bindable\]privatevar fileReference:FileReference;

\[Bindable\]private var fileSelected:Boolean = false;

\[Bindable\]private var serverUrl:String = "http://localhost:5080/Red5FileUploadProj/fileupload";private var statusArray:Array = newArray();

\[Bindable\]private var statusArrayCollection:ArrayCollection = newArrayCollection();private function doInit():void\{

fileReference= newFileReference();

fileReference.addEventListener(Event.SELECT, onFileSelect);

fileReference.addEventListener(Event.COMPLETE, onUploadComplete);

fileReference.addEventListener(ProgressEvent.PROGRESS,onUploadProgress);

fileReference.addEventListener(IOErrorEvent.IO\_ERROR, onUploadError);

fileReference.addEventListener(SecurityErrorEvent.SECURITY\_ERROR, onUploadError);

\}private function browseFile(event:MouseEvent):void\{

fileReference.browse();

\}private function onFileSelect(event:Event):void\{

fileSelected= true;

fileTxt.text=fileReference.name;

statusArray.push(\{status:"Ready to upload "+fileTxt.text\});

statusArrayCollection= newArrayCollection(statusArray);

\}private function uploadFile(event:MouseEvent):void\{if (!fileSelected || (urlTxt.text.length == 0))

Alert.show("Select a file and Enter a URL");return;

var urlRequest:URLRequest= newURLRequest(urlTxt.text);

fileReference.upload(urlRequest);

\}private function onUploadProgress(event:ProgressEvent):void\{

statusArray.push(\{status:"In progress.."+((event.bytesLoaded \* 100) / event.bytesTotal).toString()+"%"\});

statusArrayCollection= newArrayCollection(statusArray);

\}private function onUploadComplete(event:Event):void\{

statusArray.push(\{status:"Uploaded successfully!"\});

statusArrayCollection= newArrayCollection(statusArray);

\}private function onUploadError(event:Event):void\{if(event is IOErrorEvent)

statusArray.push(\{status:"IO Error: "+(event as IOErrorEvent).text.toString()\});

statusArrayCollection= newArrayCollection(statusArray);

\}else if(event is SecurityErrorEvent)

statusArray.push(\{status:"Security Error: "+(event as IOErrorEvent).text.toString()\});

statusArrayCollection= newArrayCollection(statusArray);

\]\]>

服务器端的 Java Servlet 代码使用一个 Apache 的第三方类库 Commons FileUpload 包，它可以使我们的 servlets 或者 web 应用程序具有上传的功能。这个包可以从这里进行下载：http://commons.apache.org/fileupload/。Commons FileUpload 包内部使用了 Apache Commons IO 包，所以我们把这个包也下下来：http://commons.apache.org/io/。在本文的例子中，我使用的是 commons-fileupload-1.2.1.jar 和 commons-io-1.4.jar。将 commons-fileupload-1.2.1.jar、commons-io-1.4.jar 和 servlet-api.jar 复制到 RED5 项目的 /WEB-INF/lib 目录下。其中 servlet-api.jar 可以去 tomcat 安装目录下的 lib 文件夹下去找。

然后，在我们的 RED5 应用程序的 web.xml 文件夹下添加如下内容：

fileupload

com.mycompany.ind.red5.FileUploadServlet

uploadFolder

uploads

fileupload

/fileupload

如果你熟悉 JEE，你会发现和 tomcat 的 web.xml 配置基本一致：servlet-mapping 元素将匹配 /fileupload 的 url 到名为 "fileupload" 的 servlet，servlet 元素则指示出该 servlet 具体实现类；上传的文件夹名作为 servlet 的初始参数也在这里进行定义，这里定义为 "uploads"，所以应该在我们的 RED5 项目根目录下创建一个同名文件夹。

最后，写具体实现上传的 FileUploadServlet 类：

packagecom.mycompany.ind.red5;importjavax.servlet.ServletException;importjavax.servlet.http.HttpServlet;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importorg.apache.commons.fileupload.FileItem;importorg.apache.commons.fileupload.FileItemFactory;importorg.apache.commons.fileupload.FileUploadException;importorg.apache.commons.fileupload.disk.DiskFileItemFactory;importorg.apache.commons.fileupload.servlet.ServletFileUpload;importjava.io.IOException;importjava.util.Iterator;importjava.util.List;importjava.io.FileOutputStream;importjava.io.FileNotFoundException;public class FileUploadServlet extendsHttpServlet

@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throwsServletException, IOException

\{super.doGet(request, response);

doPost(request,response);

@Overridepublic voiddoPost( HttpServletRequest request, HttpServletResponse response )

\{/\*\*\* Create a factory for new disk-based file items\*/FileItemFactory factory= newDiskFileItemFactory();/\*\*\* Create a new file upload handler\*/ServletFileUpload upload= newServletFileUpload(factory);try\{/\*\*\* Parsing input request\*/List items=upload.parseRequest(request);/\*\*\* Process the uploaded items\*/Iterator iter=items.iterator();while(iter.hasNext())

FileItem item=(FileItem) iter.next();/\*\*\* handling a normal form-field\*/

if(item.isFormField())

System.out.println("A form field");

\}else\{/\*\*\* handling file uploads\*/System.out.println("Not a form field");

String uploadFileName=item.getName();byte\[\] data =item.get();/\*\*\* Gets directory to which the file is to be uploaded\*/String uploadFolder= getServletConfig().getInitParameter("uploadFolder");

String fileFolderName= getServletContext().getRealPath(uploadFolder + "\\\\"+uploadFileName);try\{

FileOutputStream fileOutSt= newFileOutputStream(fileFolderName);try\{

fileOutSt.write(data);

fileOutSt.close();

\}catch(IOException exception)

exception.printStackTrace();

\}catch(FileNotFoundException exception)

exception.printStackTrace();

\}catch(FileUploadException exception)

exception.printStackTrace();