InitializingBean 与 CommandLineRunner(或者ApplicationRunner) 两个接口里面都提供了启动后调用的抽象方法用于我们进行拓展。日常使用时，两者皆可。

@FunctionalInterface
public interface CommandLineRunner extends Runner {

    /**
     * Callback used to run the bean.
     * @param args incoming main method arguments
     * @throws Exception on error
     */
    void run(String... args) throws Exception;

}

public interface InitializingBean {

    /**
     * Invoked by the containing {@code BeanFactory} after it has set all bean properties
     * and satisfied {@link BeanFactoryAware}, {@code ApplicationContextAware} etc.
     * <p>This method allows the bean instance to perform validation of its overall
     * configuration and final initialization when all bean properties have been set.
     * @throws Exception in the event of misconfiguration (such as failure to set an
     * essential property) or if initialization fails for any other reason
     */
    void afterPropertiesSet() throws Exception;

}

两者的区别如下:
1、调用时机 CommandLineRunner 要晚于 InitializingBean 调用
2、InitializingBean 在bean初始化后调用，而CommandLineRunner是在整个环境初始化完成后调用