Apache commons file upload

[Noopur Kore]

Here I'm trying to upload a file and write it's content in my JSP. Here's my code :

   if (!ServletFileUpload.isMultipartContent(request)) {
            return;
        }
        DiskFileItemFactory factory = new DiskFileItemFactory();
        factory.setSizeThreshold(THRESHOLD_SIZE);
        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
        ServletFileUpload upload = new ServletFileUpload(factory);
        upload.setFileSizeMax(MAX_FILE_SIZE);
        upload.setSizeMax(REQUEST_SIZE);
        String uploadPath = getServletContext().getRealPath("")
            + File.separator + UPLOAD_DIRECTORY;
        String file = null;
        File uploadDir = new File(uploadPath);
        if (!uploadDir.exists()) {
            uploadDir.mkdir();
        }
         
        try {
            List formItems = upload.parseRequest(request);
            Iterator iter = formItems.iterator();
            while (iter.hasNext()) {
                FileItem item = (FileItem) iter.next();
                if (!item.isFormField()) 
                {
                    file= item.getString();
                }
                request.getSession().setAttribute("file", file);
                response.sendRedirect("/jsp/upload.html");
            }

Here my string file appears to be empty. Can someone please tell me where am I going wrong?
Because while debugging I can see the file being uploaded to the servlet but I'm unable to retrieve contents of the file. Please help.

[Noopur Kore]

 List items = uploadHandler.parseRequest(request);
            Iterator iterator = items.iterator();
            while(iterator.hasNext()) {
                FileItem item = (FileItem) iterator.next();
 
                //Handle Form Fields
                if(item.isFormField()) {
                    System.out.println("Field Name = " + item.getFieldName() + ", Value = " + item.getString());
                    if(item.getFieldName().trim().equalsIgnoreCase("filename")){
                        fileName = item.getString().trim();
                    }
                } 
 
                //Handle Uploaded files.
                else {
                    System.out.println("Field Name = " + item.getFieldName()+
                            ", File Name = "+ item.getName()+
                            ", Content type = "+item.getContentType()+
                            ", File Size = "+item.getSize());
                    fullName = item.getName().trim();
 
                    //Write file to the ultimate location.
                    file = new File(destinationDir,item.getName());
                    item.write(file);
                }

I got this code from my friend. Can someone please help me in understanding how this while loop is working?

[Swastik Dey]

Iterator iterator = items.iterator();

The iterator above is collection of objects retrieved in request object. Then you are iterating through that collection using the loop, and comparing the type of object i.e whether its a form field (text,checkbox,radio etc) or a file type object i.e input type=file.