Five ways to implement the execution method after SpringBoot starts

After the SpringBoot project is started, there are five ways to execute the method:

1. Implement the CommandLineRunner interface

The method will be called and the service will be provided after the project is initialized.

@Component
public class StartInit2 implements CommandLineRunner {

    @Override
    public void run(String... args) throws Exception {
        ("CommandLineRunner====================");
    }
}

2. Implement the ApplicationRunner interface

Same as CommandLineRunner. It's just that the transmission format is different. CommandLineRunner: No restrictions; ApplicationRunner: key-value

@Component
public class StartInit3 implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) {
        ("ApplicationRunner=================");
    }
}

3. Implement the ApplicationListener interface

The method will be called to provide services only after the project is initialized. Pay attention to the listening events, usually ApplicationStartedEvent or ApplicationReadyEvent, and other events may not be injected into the bean.

@Component
public class StartInit4 implements ApplicationListener<ApplicationStartedEvent> {

    @Override
    public void onApplicationEvent(ApplicationStartedEvent event) {
        ("ApplicationListener================ApplicationStartedEvent");
    }
}

• If the monitor isApplicationStartedEventEvents, the ApplicationListener will be executed before CommandLineRunner and ApplicationRunner;
• If the monitor isApplicationReadyEventEvents, the ApplicationListener will be executed after CommandLineRunner and ApplicationRunner;

order:

The default isApplicationRunnerExecute first, if both parties specify@OrderThen follow@OrderThe size order of the small ones are executed first.

principle:

1. The run method of SpringApplication will execute the afterRefresh method.
2. The afterRefresh method executes the callRunners method.
3. callRunners method will call all methods that implement ApplicationRunner and CommonLineRunner interface callRunners method will call all methods that implement ApplicationRunner and CommonLineRunner interfaces callRunners method will call all methods that implement ApplicationRunner and CommonLineRunner interfaces

4. @PostConstruct annotation

This method is called during project initialization. If the business logic is time-consuming, it may cause the project to start failure.

@Component
public class StartInit {

    @PostConstruct
    public void init() {
        ("@PostConstruct===============================");
    }

}

5. Implement the InitializingBean interface

This method is called when the project starts

@Component
public class StartInit6 implements InitializingBean {

    @Override
    public void afterPropertiesSet() {
        ("InitializingBean====================");
    }

}

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.