1. 注解
      1. @Component（@Configuration、@Controller、…）
    2. @Bean
    3. @Import
    4. @ImportResource
    5. BeanDefintionRegistryPostProcessor BeanFactoryPostProcessor
    6. FactoryBean：@Autowired无法注入，有点像懒加载
    7. SmartFactoryBean：isEagerInit直接初始化，
    8. applicationContext注册Bean
      1. register(xxx.class)
      2. registerBean(beanName,beanClass,supplier)
      3. registerBeanDefiniton