你有几个选择:

使用CommandLineRunner或ApplicationRunner作为Bean定义:

Spring Boot在应用程序启动过程的末尾执行这些命令。在大多数情况下，CommandLineRunner将完成这项工作。下面是一个用Java 8实现CommandLineRunner的例子:

@Bean
public CommandLineRunner commandLineRunner() {
   return (args) -> System.out.println("Hello World");
}

请注意，args是参数的字符串数组。你也可以提供这个接口的实现，并将其定义为Spring组件:

@Component
public class MyCommandLineRunner implements CommandLineRunner {

    @Override
    public void run(String... args) throws Exception {
        System.out.println("Hello World");
    }
}

如果需要更好的参数管理，可以使用ApplicationRunner。ApplicationRunner接受一个具有增强参数管理选项的ApplicationArguments实例。

你也可以使用Spring的@Order注释来排序CommandLineRunner和ApplicationRunner bean:

 @Bean
 @Order(1)
 public CommandLineRunner commandLineRunner() {
    return (args) -> System.out.println("Hello World, Order 1");
 }

 @Bean
 @Order(2)
 public CommandLineRunner commandLineRunner() {
    return (args) -> System.out.println("Hello World, Order 2");
 }

使用Spring Boot的ContextRefreshedEvent:

Spring Boot在启动时发布几个事件。这些事件表示应用程序启动过程中某个阶段的完成。你可以监听ContextRefreshedEvent并执行自定义代码:

@EventListener(ContextRefreshedEvent.class)
public void execute() {
    if(alreadyDone) {
      return;
    }
    System.out.println("hello world");
} 

ContextRefreshedEvent被发布了几次。因此，确保检查代码执行是否已经完成。

ApplicationReadyEvent仅在您希望执行的任务不是正确服务器操作所必需的情况下才有用。启动异步任务来监视某些内容的更改就是一个很好的例子。

然而，如果你的服务器在任务完成之前处于“未准备好”状态，那么最好实现SmartInitializingSingleton，因为你会在你的REST端口被打开和你的服务器为业务打开之前得到回调。

不要试图将@PostConstruct用于只应该发生一次的任务。当你注意到它被多次调用时，你会感到粗鲁的惊讶……

你试过ApplicationReadyEvent吗?

@Component
public class ApplicationStartup 
implements ApplicationListener<ApplicationReadyEvent> {

  /**
   * This event is executed as late as conceivably possible to indicate that 
   * the application is ready to service requests.
   */
  @Override
  public void onApplicationEvent(final ApplicationReadyEvent event) {

    // here your code ...

    return;
  }
}

代码来自:http://blog.netgloo.com/2014/11/13/run-code-at-spring-boot-startup/

下面是文档中提到的启动事件:

... Application events are sent in the following order, as your application runs: An ApplicationStartedEvent is sent at the start of a run, but before any processing except the registration of listeners and initializers. An ApplicationEnvironmentPreparedEvent is sent when the Environment to be used in the context is known, but before the context is created. An ApplicationPreparedEvent is sent just before the refresh is started, but after bean definitions have been loaded. An ApplicationReadyEvent is sent after the refresh and any related callbacks have been processed to indicate the application is ready to service requests. An ApplicationFailedEvent is sent if there is an exception on startup. ...

在Spring Boot应用程序启动后执行代码块的最佳方法是使用PostConstruct注释。或者你也可以使用命令行运行器。

1. 使用PostConstruct注释

@Configuration
public class InitialDataConfiguration {

    @PostConstruct
    public void postConstruct() {
        System.out.println("Started after Spring boot application !");
    }

}

2. 使用命令行运行器bean

@Configuration
public class InitialDataConfiguration {

    @Bean
    CommandLineRunner runner() {
        return args -> {
            System.out.println("CommandLineRunner running in the UnsplashApplication class...");
        };
    }
}

Spring引导提供了一个带有run()方法的ApplicationRunner接口，在应用程序启动时调用该方法。 但是，我们有一个ApplicationArguments类的实例，而不是传递给回调方法的原始String参数。

@Component
public class AppStartupRunner implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) throws Exception {
        //some logic here
    }
}

“Spring Boot”方式是使用CommandLineRunner。只需添加该类型的bean，就可以了。在Spring 4.1 (Boot 1.2)中，也有一个SmartInitializingBean，它在所有东西初始化后得到一个回调。还有SmartLifecycle(来自Spring 3)。