GWT上傳失敗App引擎

Question

我想通過「GWT上傳」（https://code.google.com/p/gwtupload/）向Google App Engine提供文件上傳。在上傳期間，我收到一個錯誤。作爲UploadAction servlet的我用的是構建在：gwtupload.server.gae.AppEngineUploadAction

該servlet被配置在web.xml通過以下方式：

<context-param> 
    <!-- max size of the upload request --> 
    <param-name>maxSize</param-name> 
    <param-value>3145728</param-value> 
</context-param> 
<context-param> 
    <!-- Useful in development mode to slow down the uploads in fast networks. 
     Put the number of milliseconds to sleep in each block received in the server. 
     false or 0, means don't use slow uploads --> 
    <param-name>slowUploads</param-name> 
    <param-value>200</param-value> 
</context-param> 

<servlet> 
    <servlet-name>uploadServlet</servlet-name> 
    <!-- This is the default servlet, it puts files in session --> 
    <servlet-class>gwtupload.server.gae.AppEngineUploadAction</servlet-class> 
</servlet> 
<servlet-mapping> 
    <servlet-name>uploadServlet</servlet-name> 
    <url-pattern>*.gupld</url-pattern> 
</servlet-mapping> 

在上傳進度條前進的一些百分比，然後顯示以下錯誤：

但也有在日誌中沒有更多的細節。

錯誤消息顯示類別gwtupload.server.gae.MemCacheFileItemFactory$CacheableFileItem與方法setHeader()。這很奇怪，因爲我找不到該類中的方法。這裏發生了什麼事？

編輯： 這基本上是我使用的所有自定義代碼。在服務器端，我使用gwtupload.server.gae.AppEngineUploadAction servlet構建。

package com.uploadtest.client; 

import gwtupload.client.IUploadStatus.Status; 
import gwtupload.client.IUploader; 
import gwtupload.client.IUploader.UploadedInfo; 
import gwtupload.client.MultiUploader; 
import gwtupload.client.PreloadedImage; 
import gwtupload.client.PreloadedImage.OnLoadPreloadedImageHandler; 

import com.google.gwt.core.client.EntryPoint; 
import com.google.gwt.user.client.ui.FlowPanel; 
import com.google.gwt.user.client.ui.RootPanel; 

/** 
* Entry point classes define <code>onModuleLoad()</code>. 
*/ 
public class GWTUploadTest2 implements EntryPoint { 


    // A panel where the thumbnails of uploaded images will be shown 
    private FlowPanel panelImages = new FlowPanel(); 

    public void onModuleLoad() { 
     // Attach the image viewer to the document 
     RootPanel.get("thumbnails").add(panelImages); 

     // Create a new uploader panel and attach it to the document 
     MultiUploader defaultUploader = new MultiUploader(); 
     RootPanel.get("default").add(defaultUploader); 

     // Add a finish handler which will load the image once the upload finishes 
     defaultUploader.addOnFinishUploadHandler(onFinishUploaderHandler); 
    } 

    // Load the image in the document and in the case of success attach it to the viewer 
    private IUploader.OnFinishUploaderHandler onFinishUploaderHandler = new IUploader.OnFinishUploaderHandler() { 
     public void onFinish(IUploader uploader) { 
      if (uploader.getStatus() == Status.SUCCESS) { 

       new PreloadedImage(uploader.fileUrl(), showImage); 

       // The server sends useful information to the client by default 
       UploadedInfo info = uploader.getServerInfo(); 
       System.out.println("File name " + info.name); 
       System.out.println("File content-type " + info.ctype); 
       System.out.println("File size " + info.size); 

       // You can send any customized message and parse it 
       System.out.println("Server message " + info.message); 
      } 
     } 
    }; 

    // Attach an image to the pictures viewer 
    private OnLoadPreloadedImageHandler showImage = new OnLoadPreloadedImageHandler() { 
     public void onLoad(PreloadedImage image) { 
      image.setWidth("75px"); 
      panelImages.add(image); 
     } 
    }; 

} 

此外，我增加了以下罐子我clath路徑：

• 的log4j-1.2.17.jar
• gwtupload-GAE-0.6.6.jar
• gwtupload -0.6.6.jar
• 公地文件上傳-1.3.jar
• 公地-IO-2.4.jar

還拉上我的整個樣本項目，並在這裏上傳吧：

https://skydrive.live.com/redir?resid=60B826E451F52B4D!118&authkey=!ALa1n2mL2sRR0wU

編輯2：

像莫羅指出：我使用 「公地文件上傳-1.3.jar」，而不是「commons-fileupload-1.2.1.jar」。更換jar修復了我的問題！

Answer 1

的問題是在你使用的是公共資源，文件上傳的版本，將其更改爲1.2.1版，這是在gwtupload documentation的一個指向。

它應與1.2.2工作爲好，但使用1.3需要新的方法（setHeaders），這是不具備gwtupload的UploadListeners。

你應該在你的項目目標的Java（JDK遵從）更改爲1.6，因爲它是在GWT支持，以避免問題的最後一個，雖然它在1.7上運行。