Question

I’m looking for a solution for storing unique file names for a web application using Java Servlet.

What I need is to render profile images in a webpage, since I decided to store only file names in the database I have only to be sure they’re unique in the image folder: to achieve that I was thinking to name images and save them with a string name composed by the couple:

<user_id>_<hash>.<file-type> 

In this manner I think I would be pretty sure there will be no collisions, since user_ids are already unique.

1) Is this solution sound?

2) What algorithm should I pick for this purpose?

I’d like to use it properly so code snippets would be very appreciated.

Thanks

Answer 1

Really simple approach would be to append System.currentTimeMillis() to the userid. If userid is unique then it should be pretty safe.