Is it possible to fetch data from database before server is getting started?

Question

I am working on a Spring project. I want to use scheduler in it and want to schedule it on a variable date. This date has to be taken from database. Is it possible to fetch data from database before server is getting started?

Answer 1

Two solutions come to my mind:

• @PostConstruct annotated method of some @Component:

  @Component
  public class MyBean 
  {
  
     @PostConstruct
     public void init() 
     {
        // Blocking DB call could go here
     }
  
  }
  

• Application Events. For the ApplicationReadyEvent:

  @Component
  public class ApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent>
  {
  
     @Override
     public void onApplicationEvent(ApplicationReadyEvent event) 
     {
        // DB call could go here
        //
        // Notice that if this is a web services application, it
        // would potentially be serving requests while this method
        // is being executed
     }
  
  }