Flex文件上传下载

发布时间：2020-12-15 01:20:18 所属栏目：百科来源：网络整理
导读：2009-07-28Flex文件上传下载博客分类： Flex FlexServletAdobe浏览器Apache在Flex中，同样支持使用HTTP,multipart/form-data格式上传文件。还支持冲URL下载文件到本地，当然也可以直接跳转浏览器到下载链接，让下载工具来下。一、文件上传:分为Flex客户端，
 
2009-07-28
Flex文件上传下载 
博客分类： 
Flex 
FlexServletAdobe浏览器Apache
在Flex中，同样支持使用HTTP,multipart/form-data格式上传文件。还支持冲URL下载文件到本地，当然也可以直接跳转浏览器到下载链接，让下载工具来下。

一、文件上传:
分为Flex客户端，和Servlet服务器端。服务器端使用apache-common-filupload库上传。

客户端
Js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;   
            //文件上传类   
            private var fileRefer:FileReference=new FileReference();   
            private function doUpload():void{   
                //添加事件   
                //用户选中文件后执行的事件   
                fileRefer.addEventListener(Event.SELECT,selectHandler);   
                //上传完成之后执行的事件   
                fileRefer.addEventListener(Event.COMPLETE,processResult);   
                fileRefer.addEventListener(ProgressEvent.PROGRESS,progress);   
                var filter:FileFilter = new FileFilter("Text","*.mpg");   
                //打开选择文件对话框   
                var flag:Boolean=fileRefer.browse([filter]);   
            }   
            private function selectHandler(event:Event):void{   
                //根据URL执行文件上传，请求到后台Java的Servlet   
                var urlStr:String="http://localhost:8080/fileServer/FileUploadServlet";   
                var r:URLRequest=new URLRequest(urlStr);   
                fileRefer.upload(r);//第二个参数指定文件域的名字，默认为Filedata       
                //提交三个参数Filename,Filedata,Upload               
            }   
            private function processResult(event:Event):void{   
                Alert.show("上传成功!");   
            }   
               
            private function progress(event:ProgressEvent):void{   
                progressBar.setProgress(event.bytesLoaded,event.bytesTotal);   
                progressBar.label = "上传进度:" + int(event.bytesLoaded / event.bytesTotal * 100) + "%";   
            }   
               
        ]]>   
    </mx:Script>       
  
    <mx:VBox horizontalCenter="0" verticalCenter="0">   
        <mx:Button label="上传文件" click="doUpload()" />   
        <mx:ProgressBar id="progressBar" labelPlacement="bottom" themeColor="#F20D7A"  
                minimum="0" visible="true" maximum="100" label="上传进度:0%"  
                direction="right" mode="manual" width="100"/>     
    </mx:VBox>   
</mx:Application>  
<?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;
            //文件上传类
            private var fileRefer:FileReference=new FileReference();
            private function doUpload():void{
                //添加事件
                //用户选中文件后执行的事件
                fileRefer.addEventListener(Event.SELECT,selectHandler);
                //上传完成之后执行的事件
                fileRefer.addEventListener(Event.COMPLETE,processResult);
                fileRefer.addEventListener(ProgressEvent.PROGRESS,progress);
                var filter:FileFilter = new FileFilter("Text","*.mpg");
                //打开选择文件对话框
                var flag:Boolean=fileRefer.browse([filter]);
            }
            private function selectHandler(event:Event):void{
                //根据URL执行文件上传，请求到后台Java的Servlet
                var urlStr:String="http://localhost:8080/fileServer/FileUploadServlet";
                var r:URLRequest=new URLRequest(urlStr);
                fileRefer.upload(r);//第二个参数指定文件域的名字，默认为Filedata    
                //提交三个参数Filename,Upload            
            }
            private function processResult(event:Event):void{
                Alert.show("上传成功!");
            }
            
            private function progress(event:ProgressEvent):void{
                progressBar.setProgress(event.bytesLoaded,event.bytesTotal);
                progressBar.label = "上传进度:" + int(event.bytesLoaded / event.bytesTotal * 100) + "%";
            }
            
        ]]>
    </mx:Script>    

    <mx:VBox horizontalCenter="0" verticalCenter="0">
        <mx:Button label="上传文件" click="doUpload()" />
        <mx:ProgressBar id="progressBar" labelPlacement="bottom" themeColor="#F20D7A"
                minimum="0" visible="true" maximum="100" label="上传进度:0%"
                direction="right" mode="manual" width="100"/>  
    </mx:VBox>
</mx:Application>
 

主要使用FileReference类，调用其Browse方法，弹出文件选择框，提示用户选择要长传的文件。还可以使用FileFilter设置上传文件过滤，browse方法接受一个文件过滤数组。监听Event.SELECT事件，用户选择文件后触发，调用upload方法向url上传文件。 Event.COMPLETE在文件上传完成后触发。通过监听ProgressEvent.PROGRESS，设置文件长传进度条。 progressBar.setProgress(event.bytesLoaded,event.bytesTotal)。bytesLoaded为已上传大小，bytesTotal为总大小。
上传文件的默认字段名为Filedata，可以通过upload方法的第二个参数指定。 

Servlet服务器端
使用的apache-common-fileupload也比较常用，就不多说了。

 

Java代码  
public class FileUploadServlet extends HttpServlet {   
  
  
    private static final long serialVersionUID = 1L;   
  
    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException {   
        DiskFileItemFactory factory = new DiskFileItemFactory();   
  
        ServletFileUpload fileUpload = new ServletFileUpload(factory);   
        fileUpload.setSizeMax(1024 * 1025 * 1024);   
  
        try {   
            List items = fileUpload.parseRequest(request);   
            Iterator iter = items.iterator();   
            while (iter.hasNext()) {   
                FileItem item = (FileItem) iter.next();   
  
                if (item.isFormField()) {   
                    String name = item.getFieldName();   
                    String value = item.getString();   
                    System.out.println(name + ":" + value);   
                } else {   
                    String fieldName = item.getFieldName();   
                    String fileName = item.getName();   
                    String contentType = item.getContentType();   
                    boolean isInMemory = item.isInMemory();   
                    long sizeInBytes = item.getSize();   
                    String path = getServletContext().getRealPath("/");   
                    File uploadedFile = new File(path +   
                            + new Random().nextInt(Integer.MAX_VALUE) + "_"  
                            + fileName);   
                    item.write(uploadedFile);   
                }   
            }   
        } catch (FileUploadException e) {   
            e.printStackTrace();   
        } catch (Exception e) {   
            e.printStackTrace();   
        }   
  
    }   
}  
public class FileUploadServlet extends HttpServlet {


    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request,IOException {
        DiskFileItemFactory factory = new DiskFileItemFactory();

        ServletFileUpload fileUpload = new ServletFileUpload(factory);
        fileUpload.setSizeMax(1024 * 1025 * 1024);

        try {
            List items = fileUpload.parseRequest(request);
            Iterator iter = items.iterator();
            while (iter.hasNext()) {
                FileItem item = (FileItem) iter.next();

                if (item.isFormField()) {
                    String name = item.getFieldName();
                    String value = item.getString();
                    System.out.println(name + ":" + value);
                } else {
                    String fieldName = item.getFieldName();
                    String fileName = item.getName();
                    String contentType = item.getContentType();
                    boolean isInMemory = item.isInMemory();
                    long sizeInBytes = item.getSize();
                    String path = getServletContext().getRealPath("/");
                    File uploadedFile = new File(path +
                            + new Random().nextInt(Integer.MAX_VALUE) + "_"
                            + fileName);
                    item.write(uploadedFile);
                }
            }
        } catch (FileUploadException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}
 

二、文件下载：
Servlet服务器端：
Java代码  
public class FileDownloadServlet extends HttpServlet {   
    private static final long serialVersionUID = 1L;   
  
    protected void doPost(HttpServletRequest request,IOException {   
        String fileName = "hello.txt";   
        response.setContentType("text/plain");   
        response.setHeader("Content-disposition","attachment;filename="  
                + fileName);   
        byte[] data = "Hello,world!".getBytes(Charset.forName("GBK"));   
        OutputStream out = response.getOutputStream();   
        out.write(data);   
        out.flush();   
        out.close();   
    }   
  
    protected void doGet(HttpServletRequest req,HttpServletResponse resp)   
            throws ServletException,IOException {   
        doPost(req,resp);   
    }   
  
}  
public class FileDownloadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request,IOException {
        String fileName = "hello.txt";
        response.setContentType("text/plain");
        response.setHeader("Content-disposition","attachment;filename="
                + fileName);
        byte[] data = "Hello,world!".getBytes(Charset.forName("GBK"));
        OutputStream out = response.getOutputStream();
        out.write(data);
        out.flush();
        out.close();
    }

    protected void doGet(HttpServletRequest req,HttpServletResponse resp)
            throws ServletException,IOException {
        doPost(req,resp);
    }

}
 

下载了一个文件名为hello.txt的文件，内容为Hello,world!

Flex客户端:
Js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 flash.net.navigateToURL;   
           
         private var downloadURL:URLRequest;   
           private var file:FileReference;   
  
       
         public function doDownload():void {   
            //方法一   
             navigateToURL(new URLRequest("http://localhost:8080/fileServer/FileDownloadServlet"),"_blank");   
                
            //方法二   
            /*  
              downloadURL = new URLRequest("http://localhost:8080/fileServer/FileDownloadServlet");  
            file = new FileReference();  
            configureListeners(file);  
            file.download(downloadURL);  
            */  
         }   
  
         private function configureListeners(dispatcher:IEventDispatcher):void {   
            dispatcher.addEventListener(Event.CANCEL,cancelHandler);   
            dispatcher.addEventListener(Event.COMPLETE,completeHandler);   
            dispatcher.addEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler);   
            dispatcher.addEventListener(Event.OPEN,openHandler);   
            dispatcher.addEventListener(ProgressEvent.PROGRESS,progressHandler);   
            dispatcher.addEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler);   
            dispatcher.addEventListener(Event.SELECT,selectHandler);   
        }   
           
        //............省略事件处理函数   
        ]]>   
    </mx:Script>       
  
  
  
    <mx:VBox horizontalCenter="0" verticalCenter="0">   
        <mx:Button label="下载文件" click="doDownload()" />   
    </mx:VBox>   
</mx:Application>  
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">

    <mx:Script>
        <![CDATA[
         import flash.net.navigateToURL;
        
         private var downloadURL:URLRequest;
           private var file:FileReference;

    
         public function doDownload():void {
            //方法一
             navigateToURL(new URLRequest("http://localhost:8080/fileServer/FileDownloadServlet"),"_blank");
             
            //方法二
            /*
              downloadURL = new URLRequest("http://localhost:8080/fileServer/FileDownloadServlet");
            file = new FileReference();
            configureListeners(file);
            file.download(downloadURL);
            */
         }

         private function configureListeners(dispatcher:IEventDispatcher):void {
            dispatcher.addEventListener(Event.CANCEL,cancelHandler);
            dispatcher.addEventListener(Event.COMPLETE,completeHandler);
            dispatcher.addEventListener(IOErrorEvent.IO_ERROR,ioErrorHandler);
            dispatcher.addEventListener(Event.OPEN,openHandler);
            dispatcher.addEventListener(ProgressEvent.PROGRESS,progressHandler);
            dispatcher.addEventListener(SecurityErrorEvent.SECURITY_ERROR,securityErrorHandler);
            dispatcher.addEventListener(Event.SELECT,selectHandler);
        }
        
        //............省略事件处理函数
        ]]>
    </mx:Script>    



    <mx:VBox horizontalCenter="0" verticalCenter="0">
        <mx:Button label="下载文件" click="doDownload()" />
    </mx:VBox>
</mx:Application>
  
下载文件使用了两种方法

方法一最简单，直接跳转到下载链接(迅雷应该启动了)。
方法二同样使用FileReference，调用download方法，弹出对话框让用户选择下载的文件名。方法二有一个麻烦的地方就是，这里的默认文件名是FileDownloadServlet，因为其在下载前就弹出对话框让用户选择下载文件的存放路径，所以无法解析http头中的Content- disposition或filename信息，只有使用其他方式从服务器端取得默认文件名，比较麻烦。
（编辑：李大同）
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