App Engine - BlobStore- how to reference a blob by key?

Question

I am writing a servlet which will get a blob out of blobstore by referencing the blobkey. I looked online but didn't find any good examples. The google site has following example:

BlobKey key = new BlobKey(blobkey);
BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
blobstoreService.serve(key, resp);

So the client knows the blobkey and it sends it to the servlet. The servlet should use the key to get the blob out of blobstore and send it back in a response.

Any suggestions? In java please.

Thanks Sarah

The above example is doing exactly that - serving the contents of blob. What seems to be the problem? — Peter Knego

R Samuel Klatchko R Samuel Klatchko · Accepted Answer · 2012-04-21T06:55:05

If you are trying to read the contents of the blob into your app and do something with it, you should check out BlobstoreInputStream. The code would look something like:

BlobKey key = new BlobKey(blobkey);
InputStream is = new BlobInputStream(key);

You can now read the contents of the blob using any of the read() methods of InputStream.

App Engine - BlobStore- how to reference a blob by key?

1 Answers