BLOB Streaming.

YNight · **Joined:** Tue Mar 20, 2007 11:48 am **Posts:** 11

Hi all,

I'm working on a project in which we are handling file upload/download.
I am thinking about an implementation that lets us upload and download files to and from the database using Hibernate, without ever holding the files in memory.
I'm wondering if there is a nice way to do this using Hibernate.

This is an example of what I would like to do:

Code:

Attachment attachment = ... (query attachment)
streamToClient(Attachment.getDataInput()) //Data is not in memory, but holds a stream to it.

and

save(File file) {
     Attachment attachment = new Attachment();
     streamToDB(Attachment.getDataOutput()) //Data is not in memory, but hold a stream to it.
}

Any help would be appreciated.

cbredesen · **Posted:** Wed Dec 10, 2008 4:49 pm

If you map your property as a BLOB (not byte[]) then you can actually use the BLOB stream API directly. You'll have to use this API within a transaction, but it should do what you want. On the way back out, the BLOB data won't be read until you actually get the bytes out of it, and again you have to do this within a Transaction.