一、注解@PostConstruct (最早执行)
通过一个配置类（加Component注解或者Configuration注解都可以），在里面随便写一个方法，加上PostConstruct注解即可。
@Configuration
public class MyConfig {
@PostConstruct
public void get(){
System.out.println("PostConstruct");
}
}
二、实现ApplicationListener<ApplicationStartedEvent>接口（第二执行）
@Component
public class MyApplicationListener1 implements ApplicationListener<ApplicationStartedEvent> {
@Override
public void onApplicationEvent(ApplicationStartedEvent applicationStartedEvent) {
System.out.println("applicationStartedEvent");
}
}
三、实现ApplicationRunner接口（第三执行）
@Component
public class MyApplicationRunner implements ApplicationRunner {
@Override
public void run(ApplicationArguments args) throws Exception {
System.out.println("ApplicationRunner");
}
}
四、实现CommandLineRunner接口（第四执行）
@Component
public class MyCommandLineRunner implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println("CommandLineRunner"+ Arrays.toString(args));
}
}
五、实现ApplicationListener<ApplicationReadyEvent>接口（第五执行）
@Component
public class MyApplicationListener2 implements ApplicationListener<ApplicationReadyEvent> {
@Override
public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
System.out.println("applicationReadyEvent"+applicationReadyEvent);
}
}
总结
以上五种方法，除了@PostConstruct注解拿不到启动时传入的参数，其他都可以。
