upload a file using spring MultipartFile and google app engine

Question

I have been trying to upload a file by using MVC and Google App engine. Every time i am getting the error like

Expected MultipartHttpServletRequest: is a Mu

Answer 1

The following method will return a callback URL on which you need to post your file(s).

Upload Url Method

@RequestMapping(value = "/uploadurl", method = RequestMethod.GET)
public String getImageUploadUrl() {
    modelMap.addAttribute('uploadUrl',blobstoreService.createUploadUrl("/imageupload));
    return "upload";
}

Following is the JSP snippet where you will embed your code. I am putting the URL in form tag using JSTL.

JSP Page

<form action="${uploadUrl}" method="POST" enctype="multipart/form-data">
    <input type="file" name="myFile" multiple="multiple" />
</form>

Upload Handler Method

@ResponseBody
@RequestMapping(value = "/imageupload", method = RequestMethod.POST)
public void getUploadedImagesUrls(HttpServletRequest request){
    Map<String, List<BlobKey>> blobs = blobstoreService.getUploads(request);
    List<BlobKey> blobKeys = blobs.get("myFile[]");
    if (blobKeys == null) {
        return null;
    } else {
        for(BlobKey blobKey : blobKeys){
            // ImagesService services = ImagesServiceFactory.getImagesService();
            // ServingUrlOptions serve = ServingUrlOptions.Builder.withBlobKey(blobKey);
            // String imageUrl = services.getServingUrl(serve);
            BlobInfoFactory blobInfoFactory = new BlobInfoFactory();
            BlobInfo info = blobInfoFactory.loadBlobInfo(blobKey);
            System.out.println("Image URL : "+imageUrl);
            System.out.println("Image FileName : "+info.getFilename());
        }
    }
}