Q:

Using Expressions in Spring application.properties file

Can expressions be used as a right-hand-side value in a Spring application.properties file?
For example, something like this:
logging.level.com.acme=#{'${MY_RUN_ENV}'=='PROD'?'WARN':'DEBUG'}

That, specifically, does not work. But, I'm wondering if I can do something similar to what's intended there

A:

No you can not use SpEL within properties files.

Finally, while you can write a SpEL expression in @Value, such
  expressions are not processed from Application property files.

You can however use placeholders within properties files, eg:
app.name=MyApp
app.description=${app.name} is a Spring Boot application

For your use case, you should look at the profile-specific configuration mechanism.
Which allows you to load different config based on an environment profile.

