为什么要在Spring Boot中使用@PropertySource时需要指定@Configuration？

Question

I know you use @Configuration when you want to add @Bean for ApplicationContext. But why do you need to specify @Configuration when you want to use @PropertySource in Spring Boot?

Answer 1

From the API documentaion of @PropertySource :

Annotation providing a convenient and declarative mechanism for adding a PropertySource to Spring's Environment. To be used in conjunction with @Configuration classes.

So, it can be deduced that Spring will register a org.springframework.core.env.PropertySource bean if we use @PropertySource which will be managed by the Spring container. And @Configuation is needed for declaring Spring beans.