使用servlet上傳文件GWT

我正在開發一個應用程序與GWT，我試圖上傳文件到服務器（或目錄）。我正在使用表單將所選文件與FileUpload小部件一起提交。我有我使用上傳文件的servlet的一個問題：使用servlet上傳文件GWT

package com.asso.server; 

import java.io.File; 
import java.io.IOException; 
import java.util.List; 

import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

import org.apache.commons.fileupload.FileItem; 
import org.apache.commons.fileupload.FileItemFactory; 
import org.apache.commons.fileupload.disk.DiskFileItemFactory; 
import org.apache.commons.fileupload.servlet.ServletFileUpload; 
import org.apache.commons.io.FilenameUtils; 

/** 
* servlet to handle file upload requests 
* 
* @author hturksoy 
* 
*/ 
public class FileUploadServlet extends HttpServlet { 

     private static final String UPLOAD_DIRECTORY = "c:\\uploaded\\"; 
     private static final String DEFAULT_TEMP_DIR = "."; 

     @Override 
     protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
         throws ServletException, IOException { 
       // TODO Auto-generated method stub 
       super.doGet(req, resp); 
     } 

     @Override 
     protected void doPost(HttpServletRequest req, HttpServletResponse resp) 
         throws ServletException, IOException { 

       // process only multipart requests 
       if (ServletFileUpload.isMultipartContent(req)) { 

         File tempDir = getTempDir(); 
         if (!tempDir.exists()) { 
           tempDir.mkdirs(); 
         } 

         // Create a factory for disk-based file items 
         FileItemFactory factory = new DiskFileItemFactory(); 

         // Create a new file upload handler 
         ServletFileUpload upload = new ServletFileUpload(factory); 

         // Parse the request 
         try { 
           List<FileItem> items = upload.parseRequest(req); 
           for (FileItem fileItem : items) { 
             // process only file upload 
             if (fileItem.isFormField()) continue; 

             String fileName = fileItem.getName(); 
             // get only the file name not whole path 
             if (fileName != null) { 
             fileName = FilenameUtils. getName(fileName); 
            } 

             File uploadedFile = new File(UPLOAD_DIRECTORY, fileName); 
             if (uploadedFile.createNewFile()) { 
               fileItem.write(uploadedFile); 
               resp.setStatus(HttpServletResponse.SC_CREATED); 
               resp.getWriter().print("The file was created successfully."); 
               resp.flushBuffer(); 
             } else 
               throw new IOException("The file already exists in repository."); 
           } 
         } catch (Exception e) { 
           resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, 
               "An error occurred while creating the file : " + e.getMessage()); 
         } 

       } else { 
         resp.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE, 
                 "Request contents type is not supported by the servlet."); 
       } 
     } 

     private File getTempDir() { 
       return new File(DEFAULT_TEMP_DIR); 
     } 

}

我得到這個錯誤：

java.lang.NoClassDefFoundError: org/apache/commons/fileupload/FileItemFactory 
    at java.lang.Class.getDeclaredConstructors0(Native Method) 
    at java.lang.Class.privateGetDeclaredConstructors(Unknown Source) 
    at java.lang.Class.getConstructor0(Unknown Source) 
    at java.lang.Class.newInstance0(Unknown Source) 
    at java.lang.Class.newInstance(Unknown Source) 
    at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153) 
    at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:428) 
    at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339) 
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) 
    at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:61) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.DevAppServerServersFilter.doFilter(DevAppServerServersFilter.java:106) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) 
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) 
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) 
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) 
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) 
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:94) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:421) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at org.mortbay.jetty.Server.handle(Server.java:326) 
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) 
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) 
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) 
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) 
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) 
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) 
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) 
Caused by: java.lang.ClassNotFoundException: org.apache.commons.fileupload.FileItemFactory 
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.net.URLClassLoader.findClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    at com.google.appengine.tools.development.IsolatedAppClassLoader.loadClass(IsolatedAppClassLoader.java:214) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    ... 41 more

我看到了這個問題，它說，我要補充的commons-fileupload-1.3.jar和commons-io-2.4.jar我已經完成了。 How to solve this java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream? 任何解決方案？編輯：直接添加JAR文件到我的WEB-INF/lib目錄後，我得到這個錯誤

java.lang.NoClassDefFoundError: `java.io.FileOutputStream is a restricted class. Please see the Google App Engine developer's guide for more details. 
    at com.google.appengine.tools.development.agent.runtime.Runtime.reject(Runtime.java:51) 
    at org.apache.commons.io.output.DeferredFileOutputStream.thresholdReached(DeferredFileOutputStream.java:178) 
    at org.apache.commons.io.output.ThresholdingOutputStream.checkThreshold(ThresholdingOutputStream.java:224) 
    at org.apache.commons.io.output.ThresholdingOutputStream.write(ThresholdingOutputStream.java:128) 
    at org.apache.commons.fileupload.util.Streams.copy(Streams.java:108) 
    at org.apache.commons.fileupload.util.Streams.copy(Streams.java:70) 
    at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:347) 
    at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:115) 
    at com.asso.server.FileUploadServlet.doPost(FileUploadServlet.java:56) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) 
    at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:123) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:61) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.DevAppServerServersFilter.doFilter(DevAppServerServersFilter.java:106) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) 
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) 
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) 
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) 
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) 
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:94) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:421) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at org.mortbay.jetty.Server.handle(Server.java:326) 
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) 
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) 
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) 
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) 
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) 
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) 
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)`

來源

2013-04-17 Hassen Ch.

你重新啓動服務器？（關閉開發模式，並重新啓動不重啓按鈕） – David

是的，我做了很多次！ –

您是使用maven還是將apache jar複製到WEB-INF/lib中？是Dev模式還是Prod模式下的錯誤？ – SSR

確保你沒有錯過複製文件的commons-文件上傳-1.3.jar和commons-IO-2.4.jar到您的WEB-INF/lib中。你也應該檢查你的啓動類路徑的devmode。

示例 - 我已經添加了一個樣本jar到我的lib中，並可以通過我的啓動配置看到相同的結果。

更新 - 如果你正在使用GAE請通讀

enter image description here

來源

2013-04-18 03:36:37 SSR

我沒有將它們複製到WEB-INF/lib，我將它們添加爲外部JAR。但我有他們在我的建立路徑和類路徑 –

看看編輯和新的錯誤 –

避免張貼更新作爲答案！由於您試圖使用谷歌應用程序引擎您的查詢可能會通過http://stackoverflow.com/questions/1513603/how-to-upload-and-store-an-image-with-google-app-engine-java – SSR

Google App Engine應用程序cannot write to the filesystem。

您使用試圖寫入文件系統，因此你會得到以下異常的DiskFileItemFactory對象：

java.lang.NoClassDefFoundError: `java.io.FileOutputStream is a restricted class. Please see the Google App Engine developer's guide for more details.

下面是DiskFileItemFactory documentation的解釋：

此實現創建其保持的FileItem情況下，它們無論是在內存中，對於較小的項目，還是在磁盤上的臨時文件中，對於較大的項目。大小閾值（高於該閾值的內容將被存儲在磁盤上）是可配置的，因爲將創建臨時文件的目錄。如果沒有另外配置，則的默認配置值如下所示：大小閾值爲10KB。

解決方案：您應該增加文件大小閾值。覆蓋默認值。將其設置爲您想要上傳到您的servlet的最大文件大小。

DiskFileItemFactory factory= new DiskFileItemFactory(5000000,null);

或

DiskFileItemFactory factory= new DiskFileItemFactory(); 
factory.setSizeThreshold(5000000);

來源

2013-08-10 15:36:35

使用servlet上傳文件GWT

回答

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