Using Oracle Java 7 without the plug-in I need Oracle Java 7 for software running on my Mac, but do not wish to have the plug-in available in my web browsers.

How can I accomplish this configuration and maintain it across Java upgrades?
I'd say just install java as normal. Afterwards go to

System Preferences → Java (bottom row) → Security

and uncheck "Enable Java content in the web browser". 

That should do it, and I would very much expect it to remember the setting after an update.