文章轉自:https://www.cnblogs.com/redcool/p/6397398.html
Spring框架中,一旦把一個Bean納入Spring IOC容器之中,這個Bean的生命週期就會交由容器進行管理,一般擔當管理角色的是BeanFactory或者ApplicationContext,認識一下Bean的生命週期活動,對更好的利用它有很大的幫助:
下面以BeanFactory爲例,說明一個Bean的生命週期活動
- Bean的建立, 由BeanFactory讀取Bean定義文件,並生成各個實例
- Setter注入,執行Bean的屬性依賴注入
- BeanNameAware的setBeanName(), 如果實現該接口,則執行其setBeanName方法
- BeanFactoryAware的setBeanFactory(),如果實現該接口,則執行其setBeanFactory方法
- BeanPostProcessor的processBeforeInitialization(),如果有關聯的processor,則在Bean初始化之前都會執行這個實例的processBeforeInitialization()方法
- InitializingBean的afterPropertiesSet(),如果實現了該接口,則執行其afterPropertiesSet()方法
- Bean定義文件中定義init-method
- BeanPostProcessors的processAfterInitialization(),如果有關聯的processor,則在Bean初始化之前都會執行這個實例的processAfterInitialization()方法
- DisposableBean的destroy(),在容器關閉時,如果Bean類實現了該接口,則執行它的destroy()方法
- Bean定義文件中定義destroy-method,在容器關閉時,可以在Bean定義文件中使用“destory-method”定義的方法
如果使用ApplicationContext來維護一個Bean的生命週期,則基本上與上邊的流程相同,只不過在執行BeanNameAware的setBeanName()後,若有Bean類實現了org.springframework.context.ApplicationContextAware接口,則執行其setApplicationContext()方法,然後再進行BeanPostProcessors的processBeforeInitialization()
實際上,ApplicationContext除了向BeanFactory那樣維護容器外,還提供了更加豐富的框架功能,如Bean的消息,事件處理機制等。
在這裏一用倉頡的一幅圖說明流程: 轉載自 https://www.cnblogs.com/xrq730/p/6363055.html
以下是自己測試時打印的日誌信息,可以看下加載順序:
/**
* @ClassName: MySpringBean
* @Description: my spring bean to test
* @author: daniel.zhao
* @date: 2018年10月26日 上午10:12:37
*/
public class MySpringBean implements BeanNameAware, BeanFactoryAware, InitializingBean, ApplicationContextAware {
private ApplicationContext applicationContext;
private static final Logger logger = LoggerFactory.getLogger(MySpringBean.class);
public MySpringBean() {
logger.info("new MySpringBean......");
}
@Override
public void setApplicationContext(ApplicationContext context) throws BeansException {
logger.info("ApplicationContextAware-setApplicationContext......");
this.applicationContext = context;
}
@Override
public void afterPropertiesSet() throws Exception {
logger.info("InitializingBean-afterPropertiesSet......");
}
@Override
public void setBeanFactory(BeanFactory bf) throws BeansException {
logger.info("BeanFactoryAware-setBeanFactory......");
}
@Override
public void setBeanName(String name) {
logger.info("BeanNameAware-setBeanName......");
}
public void init() {
logger.info("init-method......");
}
}
/**
* @ClassName: MySpringBeanPostProcessor
* @author: daniel.zhao
* @date: 2018年10月26日 上午10:40:21
*/
@Component
public class MySpringBeanPostProcessor implements BeanPostProcessor {
private static final Logger logger = LoggerFactory.getLogger(MySpringBeanPostProcessor.class);
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if (bean instanceof MySpringBean) {
logger.info("BeanPostProcessor-postProcessAfterInitialization......");
}
return bean;
}
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
if (bean instanceof MySpringBean) {
logger.info("BeanPostProcessor-postProcessBeforeInitialization......");
}
return bean;
}
}
2018-10-26 10:49:48.768 INFO 5732 --- [ main] com.daniel.bean.MySpringBean : BeanNameAware-setBeanName......
2018-10-26 10:49:48.769 INFO 5732 --- [ main] com.daniel.bean.MySpringBean : BeanFactoryAware-setBeanFactory......
2018-10-26 10:49:48.769 INFO 5732 --- [ main] com.daniel.bean.MySpringBean : ApplicationContextAware-setApplicationContext......
2018-10-26 10:49:48.770 INFO 5732 --- [ main] c.daniel.bean.MySpringBeanPostProcessor : BeanPostProcessor-postProcessBeforeInitialization......
2018-10-26 10:49:48.770 INFO 5732 --- [ main] com.daniel.bean.MySpringBean : InitializingBean-afterPropertiesSet......
2018-10-26 10:49:48.770 INFO 5732 --- [ main] com.daniel.bean.MySpringBean : init-method......
2018-10-26 10:49:48.771 INFO 5732 --- [ main] c.daniel.bean.MySpringBeanPostProcessor : BeanPostProcessor-postProcessAfterInitialization......