实现这两个listener都可以进行自己的初始化逻辑。
InitializingBean.afterPropertiesSet 这个优先调用
ApplicationListener.onApplicationEvent 这个后调用
他们分别由 AbstractApplicationContext.refresh 方法
调用的如下两个函数调用到的:
finishBeanFactoryInitialization(beanFactory);
finishRefresh();
public class InitListener implements ApplicationListener, InitializingBean {
    @Resource
    private AboutDao aboutDao;
    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("afterPropertiesSet");
        Integer count = 0;
        try {
            count = aboutDao.count();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println(count);
    }
    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        //防止重复调用
        ApplicationContext ctx = (ApplicationContext) event.getSource();
        if (ctx.getParent() != null) {
            return;
        }
        System.out.println("onApplicationEvent");
        Integer count = 0;
        try {
            count = aboutDao.count();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println(count);
    }
}