SpringApplicationRunListeners与ApplicationListener

Question

I'm reading the source code of SpringApplication , and I found two kinds of Listener .

• There is a list of ApplicationListner as class field declared with

  private List<ApplicationListener<?>> listeners

• And in run method, I found a SpringApplicationRunListeners declared with

  SpringApplicationRunListeners listeners = getRunListeners(args);

What's the difference between them?

Thank you very much.

Answer 1

ApplicationListner - Interface to be implemented by application event listeners.

This might be helpful for better understanding of what is event is spring app https://spring.io/blog/2015/02/11/better-application-events-in-spring-framework-4-2

SpringApplicationRunListener - Listener for the SpringApplication run method. A new SpringApplicationRunListener instance will be created for each run.

Spring Boot app launches from a Java main method where you usually do something like SpringApplication.run(...) . Basically, you can use that interface to handle Spring Boot App bootstrap process events.