sha512sum files?

Does anyone know how to output a file called SHA512SUMS with the sha512sum values of the files in a directory? Something like this:
http://releases.ubuntu.com/karmic/SHA256SUMS

Thanks!

Write a Java Enterprise Solution to traverse a directory tree and use os.system.utils.crypto.sha.Sha512Sum.sha512SumFactory or whatever to access the shell to invoke my anus.