request.getParameter（“xyz”）无效

Question

hiii大家......我正在netbeans ide上做我的项目，为数据库创建一个post web服务器。我在文件上传方面遇到了一些问题..我正在从高级休息客户端发送数据以及文件... bt发送500错误...它不接受request.getParameter（“我从休息客户端提供的数据”） ....我的代码是......

else if (action.equalsIgnoreCase("fileUpload")) {
       String userId =request.getParameter("userId");

        boolean isMultipart = ServletFileUpload.isMultipartContent(request);
        if (!isMultipart) {


        } else {

            FileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload upload = new ServletFileUpload(factory);
            List items = null;
            try {

                items = upload.parseRequest(request);
            } catch (FileUploadException e) {
                e.printStackTrace();
            }
            Iterator itr = items.iterator();

            while (itr.hasNext()) {


                FileItem item = (FileItem) itr.next();
                if (item.isFormField()) {



                } 
                else {
                    try {

                        String itemName = item.getName();
                        System.out.println("FILE PATH " + getServletContext().getRealPath("/"));
                        File savedFile = new File(getServletContext().getRealPath("/") + "uploadedFiles/" + itemName);
                        item.write(savedFile);


                       String str = "build-web-uploadedFiles-" + itemName + "";

                        dao.addFile(userId, str);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }

                }

            }

        }
 }