I am working on a springboot 2.7 service and trying to understand how to use custom placeholders like ${key} vs $%key% or similar. I am not stuck on using a custom placeholder, but I also need to resolve the values with a custom service.

So that @Value can be refreshed based on time or TTL with service or WebClient that has caching built in.

I have looked at org.springframework.context.support.PropertySourcesPlaceholderConfigurer

but I am looking for a concrete example on how to implement.

Thanks