[ioc] get componet from spring, such as ioc

[Alice52]

get ioc container

1. configuration

   @Configuration
   public class IocContainer implements ApplicationContextAware {
      private ApplicationContext applicationContext;
   
      public ApplicationContext getApplicationContext() {
          return this.applicationContext;
      }
   
      @Override
      public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
          this.applicationContext = applicationContext;
      }
   
      @Bean
      public Person person() {
          return new Person();
      }
   }

2. junit test

   @Slf4j
   public class IocContainerTest {
      private ApplicationContext applicationContext = new AnnotationConfigApplicationContext(IocContainer.class);
   
      @Test
      public void testGetIocContainer() {
          IocContainer contextBean = applicationContext.getBean(IocContainer.class);
          ApplicationContext applicationContext = contextBean.getApplicationContext();
   
          Person person0 = applicationContext.getBean(Person.class);
          log.info(String.valueOf(person0));
   
          Person person = applicationContext.getBean(Person.class);
          log.info(String.valueOf(person));
   
          Assert.isTrue(person0 == person);
          Assert.isFalse(applicationContext == contextBean);
      }
   }

---

xxAware: 获取 spring 底层的组件, 只需要自定义的组件实现 xxAware 接口

1. ioc container: ApplicationContextAware
2. bean factory: BeanFactoryAware
3. ApplicationEventPublisherAware
4. ServletContextAware
5. MessageSourceAware
6. ResourceLoaderAware
7. NotificationPublisherAware
8. EnvironmentAware
9. EmbeddedValueResolverAware
10. ImportAware
11. ServletConfigAware
12. LoadTimeWeaverAware
13. BeanNameAware
14. BeanClassLoaderAware

[Alice52]

inject to ioc[methods to inject]

1. @Component/@Controller + @ComponentScan

   • 如果 @ComponentScan 使用自定义的方式或者指定包含某些类时[ASSIGNABLE_TYPE, REGEX, CUSTOM], 没有 @Component/@Controller 也可以成功注入 IOC
   • ANNOTATION 必须使用 @Component/@Controller 才能成功注入 IOC

2. @Bean 将第三方包中的组件归置到 IOC 管理

3. @Import

   • @Import
   • ImportSelector
   • ImportBeanDefinitionRegistrar
   • Spring FactoryBean: & 表示获取FactoryBean 本身; 否则会获取 FactoryBean 的 getObject 产生的对象