Question

I thought this would be a quick fun project, but it’s turning into a problem. 🙁

I want to load some images into an Oracle table and then later retrieve them with hibernate through a servlet.

So here’s the portion of the loader that inserts the image.

  String imageFileName = row[col++];
  String ext = imageFileName.substring(imageFileName.lastIndexOf('.') + 1);
  String imageFilePath = imageDir + imageFileName;
  String mimeType = "image/" + ext;
  image.setImageType(mimeType);

  Image found = imageDAO.retrieve(imageId);
  if(found==null){
    //create a new one
    byte[] bytes = loadImage(imageFilePath, mimeType);
    image.setImageData(bytes);
    image = imageDAO.create(image);
    ++created;
  }
  else{
    //check if an update is needed
    if(updateDate.after(found.getUpdated())){
      byte[] bytes = loadImage(imageFilePath, mimeType);
      found.setImageData(bytes);
      found.setUpdated(updateDate);
      image = imageDAO.update(found);
      ++updated;
    }
  }
}

and here’s the servlet innards:

  @Override
  protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {
    String imageId = request.getParameter(KeyNames.PARM_IMAGE_ID);
    if(imageId==null){
      throw new NullPointerException("Image ID parameter is required");
    }

    Image image = getImageDAO().retrieve(imageId);
    if(image==null){
      throw new IllegalArgumentException(imageId + " is not a valid image ID");
    }

    response.setContentType(image.getImageType());
    response.getOutputStream().write(image.getImageData());
    response.getOutputStream().close();

    return null;
  }

Seems simple to me, but when I hit the URL using my browser, I get:

“The image [url] cannot be displayed because it contains errors”

Since the servlet is wrapping successful, I must guess that either in the loading or in the retrieving, I’ve corrupted the image data. I’m out of guesses as to what to do next, so any advice is appreciated.

Answer 1

Shame on me! This is what I get for running code off the internet without actually studying it to find out what it does!

So the answer was that I was running the image through a writable raster in order to store in the DB. Well, DUH! when you rasterize the image, it’s not a png anymore.

So I simply do a byte copy from the input file and store that in the blob and it works fine.

Shoot me now.

Thanks for the help!