Well, it really depends on a couple of things.
First off, what is the application to run on? Windows or Unix/Linux? If you're running Unix/Linux, you'll need to take into account file and directory permissions. Depending on where you want to write the file to, does your
servlet container have read-write permissions to it?
Also, do you want to have to read and write BLOBs to your db? what kind of access time is it going to take to do this.
I've only done this with writing to a file system, but I hear of a lot apps that write to a db. With a db, you'll be able to add fields to the table that hold information on the file, like owner, last date modified(last upload time). You could also add a field that locks the record, so it can be downloaded if its checked out. You could do this as well if working with a file system, but I think it would be easier to implement using a db.
So depending on what you want to do, a db might be better, but BLOBs take up a lot of space in db table, so if space is small, maybe look to straight files.
I'd like to hear if anyone has compared the access times of the two. Which would be faster? I'd think it would be the filesystem, but I could be wrong.
HTH,
/rick