使用Play将文件上传到GAE!骨架

Uploading a file to GAE with Play! Framework

What is the best way of uploading files to Google App Engine Blobstore with Play! Framework, using Siena and GAE module?

I have tried declaring a Blob field in my Model:

public Blob image;

And a method to attach the file:

public void attachImage(byte[] bytes) {
    this.image = new Blob(bytes);
}

I don't really know how to test this since the CrudSiena module doesn't display an upload field. Any help much appreciated.

Blob is a type managed by GAE datastore but it's different from GAE Blobstore!

If you use byte[] instead of Blob in your model, does it work with CrudSiena?

Thank you, I managed to get the field in CrudSiena. But it seems like the file isn't uploaded, the image attribute is an empty byte array (length 0).
Is the field rendered as a file upload input in the CRUD? Did you reset your DataStore completely to be sure?
Yes, the field is a file upload. I have tried with an empty datastore, and I still have en empty array of bytes. The weird thing is that nothing is displayed once the form is sent, is there supposed to be a thumbnail or something?
Seeing the code, there should be a link to download the file...
do you have a sample of your model to verify I don't see anything weird?