Spring的bean生命周期

spring中bean的生命周期

一、单实例和多实例：

1、创建

单实例：在容器启动的时候创建对象
多实例：在每次获取的时候创建对象

2、初始化

对象创建完成，并赋值好，调用初始化方法

3、销毁

单实例：容器关闭的时候
多实例：容器不会管理这个bean，容器不会调用销毁方法；

二、自定义

1、指定初始化和销毁方法

@Configuration public class MainConfigOfLifeCycle { @Bean(initMethod = "init",destroyMethod = "destroy") public Car car(){ return new Car(); } } 

2、让Bean实现InitializingBean，DisposableBean

@Component public class Car implements InitializingBean, DisposableBean { public Car(){ System.out.println("car constructor"); } @Override public void destroy() throws Exception { System.out.println("car ... destroy "); } /**
     * 初始化init方法（）
     * @throws Exception
     */ @Override public void afterPropertiesSet() throws Exception { System.out.println("car......afterPropertiesSet....."); } } 九月 28, 2020 11:49:52 上午 org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@38cccef: startup date [Mon Sep 28 11:49:52 CST 2020]; root of context hierarchy
九月 28, 2020 11:49:53 上午 org.springframework.beans.factory.support.DefaultListableBeanFactory registerBeanDefinition
信息: Overriding bean definition for bean 'car' with a different definition: replacing [Generic bean: class [com.zqs.bean.Car]; scope=singleton; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in file [D:\ideaWork\spring-annotaion\target\classes\com\zqs\bean\Car.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=mainConfigOfLifeCycle; factoryMethodName=car; initMethodName=null; destroyMethodName=(inferred); defined in com.zqs.config.MainConfigOfLifeCycle] car constructor
car......afterPropertiesSet..... 容器创建完成。。。。
九月 28, 2020 11:49:53 上午 org.springframework.context.annotation.AnnotationConfigApplicationContext doClose
信息: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@38cccef: startup date [Mon Sep 28 11:49:52 CST 2020]; root of context hierarchy
car ... destroy 

Process finished with exit code 0 

3、使用注解 @PostConstruct、@PreDestroy注解

import org.springframework.stereotype.Component; import javax.annotation.PostConstruct; import javax.annotation.PreDestroy; @Component public class Car { public Car(){ System.out.println("car constructor"); } @PreDestroy public void destroy() throws Exception { System.out.println("car ... PreDestroy(销毁) "); } /**
     * 初始化init方法（）
     * @throws Exception
     */ @PostConstruct public void init() { System.out.println("car......PostConstruct（初始化）....."); } } 九月 28, 2020 4:43:22 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory registerBeanDefinition
信息: Overriding bean definition for bean 'car' with a different definition: replacing [Generic bean: class [com.zqs.bean.Car]; scope=singleton; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in file [D:\ideaWork\spring-annotaion\target\classes\com\zqs\bean\Car.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=mainConfigOfLifeCycle; factoryMethodName=car; initMethodName=null; destroyMethodName=(inferred); defined in com.zqs.config.MainConfigOfLifeCycle] car constructor
car......PostConstruct（初始化）..... 容器创建完成。。。。
九月 28, 2020 4:43:22 下午 org.springframework.context.annotation.AnnotationConfigApplicationContext doClose
信息: Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@38cccef: startup date [Mon Sep 28 16:43:21 CST 2020]; root of context hierarchy
car ... PreDestroy(销毁) Process finished with exit code 0 

4、使用BeanPostProcessor（接口）后处理器（主要是对象初始化前后对对象的处理）

重写两方法

postProcessBeforeInitialization() 初始化之前调用

postProcessAfterInitialization() 初始化之后调用

@Component public class Car { public Car(){ System.out.println("car constructor"); } @PreDestroy public void destroy() throws Exception { System.out.println("car ... PreDestroy(销毁) "); } /**
     * 初始化init方法（）
     * @throws Exception
     */ @PostConstruct public void init() { System.out.println("car......PostConstruct（初始化）....."); } } @Component public class MyBeanPostProcessor implements BeanPostProcessor { @Override public Object postProcessBeforeInitialization(Object o, String s) throws BeansException { System.out.println("postProcessBeforeInitialization....."+s ); return o; } @Override public Object postProcessAfterInitialization(Object o, String s) throws BeansException { System.out.println("postProcessAfterInitialization....."+s ); return o; } } 信息: Overriding bean definition for bean 'car' with a different definition: replacing [Generic bean: class [com.zqs.bean.Car]; scope=singleton; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in file [D:\ideaWork\spring-annotaion\target\classes\com\zqs\bean\Car.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=mainConfigOfLifeCycle; factoryMethodName=car; initMethodName=null; destroyMethodName=(inferred); defined in com.zqs.config.MainConfigOfLifeCycle] postProcessBeforeInitialization.....org.springframework.context.event.internalEventListenerProcessor
postProcessAfterInitialization.....org.springframework.context.event.internalEventListenerProcessor
postProcessBeforeInitialization.....org.springframework.context.event.internalEventListenerFactory
postProcessAfterInitialization.....org.springframework.context.event.internalEventListenerFactory
postProcessBeforeInitialization.....mainConfigOfLifeCycle
postProcessAfterInitialization.....mainConfigOfLifeCycle
car constructor
postProcessBeforeInitialization.....car
car......PostConstruct（初始化）..... postProcessAfterInitialization.....car
容器创建完成。。。。

Process finished with exit code 0 

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