ServletFileUpload使用servlet和JSP上传文件时出现parseRequest（）编译错误

Question

我正在尝试使用servlet和JSP上传图像上传。

我的JSP页是相当简单的，并且具有唯一的以下形式：

<form method="post" action="${pageContext.request.contextPath}/uploader" enctype="multipart/form-data"> 
    <input type="file" name="file" value="Select an image..." /> 
    <input type="submit" value="Upload Now" /> 
</form> 

相应servlet和servlet映射在web.xml进行说明。
而我doPost方法看起来：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    PrintWriter out = response.getWriter(); 

    FileItemFactory itemFactory = new DiskFileItemFactory(); 
    ServletFileUpload upload = new ServletFileUpload(itemFactory); 

    if (!contentType.equals("image/png")) { 
     out.println("Only PNG image files supported."); 
     continue; 
    } 

    try { 
     List<FileItem> items = upload.parseRequest(request); // here is an error 
     for (FileItem item : items) { 
      String contentType = item.getContentType(); 

      File uploadDir = new File(UPLOAD_DIR); 
      File file = File.createTempFile("img", ".png", uploadDir); 

      item.write(file); 

      out.println("File uploaded."); 
     } 
    } catch (FileUploadException e) { 
     out.println("Upload failed."); 
     return; 
    } 
} 

但是，编译以下行抱怨：List<FileItem> items = upload.parseRequest(request);：

在文件FileUploadBase方法parseRequest(RequestContext)是不适用的参数（HttpServletRequest的）。

虽然在回答How to upload files to server using JSP/Servlet?这种方法不会产生任何错误：如果我在这里看到org.apache.commons.fileupload 请求应ServletRequestContext不HttpServletRequest的

List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request); 

Answer 1

：

List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(new ServletRequestContext(request)); 

Answer 2

此代码应该解决问题

DiskFileItemFactory diskFactory = new DiskFileItemFactory(); 
diskFactory.setSizeThreshold(4000); 
diskFactory.setRepository(new File(System.getProperty("java.io.tmpdir"))); 
ServletFileUpload uploadHandler = new ServletFileUpload(diskFactory); 
List<FileItem> items = upload.parseRequest(request);