1.InitializingBean

失效此接口的类,在初始化完成之后,会自动调用afterPropertiesSet()方法,但是在init-method方法之后(如果配置)

@Componentpublic class InitializingBeanTest implements InitializingBean {    @Override    public void afterPropertiesSet() throws Exception {        System.out.println("afterPropertiesSet 被调用");    }}

2.BeanPostProcessor

bean后置处理器,它是用来拦截所有 bean 的初始化的,在 bean 的初始化之前,和初始化之后做一些事情。这点从 BeanPostProcessor 接口的定义也可以看出来,它里面就两个方法:postProcessBeforeInitialization 和 postProcessAfterInitialization。

2.1:后置处理器的postProcessorBeforeInitailization方法是在bean实例化,依赖注入之后及自定义初始化方法(例如:配置文件中bean标签添加init-method属性指定Java类中初始化方法、
@PostConstruct注解指定初始化方法,Java类实现InitailztingBean接口)之前调用
2.2:后置处理器的postProcessorAfterInitailization方法是在bean实例化、依赖注入及自定义初始化方法之后调用

@Componentpublic class BeanPostProcessorTest implements BeanPostProcessor {    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {        System.out.println("后置处理器处理bean=【"+beanName+"】开始");        return bean;    }    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {        System.out.println("后置处理器处理bean=【"+beanName+"】完毕");        return bean;    }}

3.ApplicationContextAware

当一个类实现了这个接口之后,这个类就可以方便的获得ApplicationContext对象,然后从applicationContext对象中利用getBean()获取容器中的bean

@Componentpublic class SpringContextHelper implements ApplicationContextAware {    private static ApplicationContext applicationContext;    @Override    public void setApplicationContext(ApplicationContext context) throws BeansException {        applicationContext = context;    }    public static  T getInstance(String beanName, Class beanType) {        return applicationContext.getBean(beanName, beanType);    }    public static  T getInstance(Class bean) {        return applicationContext.getBean(bean);    }}

4.BeanFactoryAware

同ApplicationContextAware对象一样,实现此接口可以获取到BeanFactory对象,然后利用getBean获取我们需要bean

@Servicepublic class BeanFactoryHelper implements BeanFactoryAware {        private static BeanFactory beanFactory;     @Override    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {        this.beanFactory = beanFactory;    }        public static Object getBean(String beanName){      if(beanFactory == null){            throw new NullPointerException("BeanFactory is null!");        }      return beanFactory.getBean(beanName);   } }

5.ApplicationRunner

在项目完全启动后,调用实现此接口的方法。

@Componentpublic class CommonRunner implements ApplicationRunner {    @Override    public void run(ApplicationArguments args) throws Exception {        System.out.println("启动后执行。。。。。");    }}

6.@PostConstruct

在bean初始化之前调用,具体和afterPropertiesSet(),还有init-method调用顺序,可以看下spring的生命周期