How can i generate a long hash of a String?

Question

I have a java applciation in which I want to generate long ids for strings (in order to store those strings in neo4j). In order to avoid data duplication, I wou

Answer 1

There are many answers, try the following:

• http://stackoverflow.com/questions/415953/generate-md5-hash-in-java EDIT: removed, I've missed the long requirement. Mea culpa.
• http://en.wikipedia.org/wiki/Perfect_hash_function

Or, as suggested before, check out the sources.

PS. One more technique is to maintain a dictionary of strings: since you're unlikely to get 2⁶⁴ strings any time soon, you can have perfect mapping. Note though that that mapping may as well become a major bottleneck.