可参考文章:
Spring开闭原则的表现-BeanPostProcessor扩展点-1
一次调试打印出来的堆栈如下:
PropertyPlaceholderConfigurer.afterPropertiesSet() line: 42
DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).invokeInitMethods(String, Object, RootBeanDefinition) line: 1687
DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).initializeBean(String, Object, RootBeanDefinition) line: 1624
DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).doCreateBean(String, RootBeanDefinition, Object[]) line: 555
DefaultListableBeanFactory(AbstractAutowireCapableBeanFactory).createBean(String, RootBeanDefinition, Object[]) line: 483
AbstractBeanFactory$1.getObject() line: 306
DefaultListableBeanFactory(DefaultSingletonBeanRegistry).getSingleton(String, ObjectFactory<?>) line: 230
DefaultListableBeanFactory(AbstractBeanFactory).doGetBean(String, Class<T>, Object[], boolean) line: 302
DefaultListableBeanFactory(AbstractBeanFactory).getBean(String, Class<T>) line: 202
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory, List<BeanFactoryPostProcessor>) line: 149
ClassPathXmlApplicationContext(AbstractApplicationContext).invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory) line: 686
ClassPathXmlApplicationContext(AbstractApplicationContext).refresh() line: 524
PropertyPlaceholderConfigurer.loadProperties(Properties) line: 37
PropertyPlaceholderConfigurer(PropertiesLoaderSupport).mergeProperties() line: 157
PropertyPlaceholderConfigurer(PropertyResourceConfigurer).postProcessBeanFactory(ConfigurableListableBeanFactory) line: 80
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(Collection<BeanFactoryPostProcessor>, ConfigurableListableBeanFactory) line: 281
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory, List<BeanFactoryPostProcessor>) line: 161
ClassPathXmlApplicationContext(AbstractApplicationContext).invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory) line: 686
ClassPathXmlApplicationContext(AbstractApplicationContext).refresh() line: 524
根据上面的堆栈信息,可以得知,调用顺序如下:
refresh -- invokeBeanFactoryPostProcessors(0) -- invokeBeanFactoryPostProcessors(0,1)line:149 -- createBean -- initializeBean -- invokeInitMethods -- afterPropertiesSet -- invokeBeanFactoryPostProcessors(0,1)line:161 -- postProcessBeanFactory
容器启动时:
最先调用
BeanFactoryPostProcessor
->postProcessBeanFactory()
getBean时:
实例化之后调用:
InstantiationAwareBeanPostProcessor
->postProcessPropertyValues()
初始化时:
属性注入(setter)
BeanNameAware
->setBeanName()
BeanFactoryAware
->setBeanFactory()
ApplicationContextAware
->setApplicationContext()
BeanPostProcessor
->postProcessBeforeInitialization()
InitializingBean
->afterPropertiesSet()
init-method属性
BeanPostProcessor
->postProcessAfterInitialization()
DiposibleBean
->destory()
destroy-method属性
BeanFactoryPostProcessor //Spring IoC容器允许BeanFactoryPostProcessor在容器实际实例化任何其它的bean之前读取配置元数据,并有可能修改它。 //同时BeanFactoryPostProcessor的回调比BeanPostProcessor要早 void postProcessBeanFactory(ConfigurableListableBeanFactory arg) InstantiationAwareBeanPostProcessorAdapter 其适配器类:InstantiationAwareBeanPostProcessor //实例化Bean之前调用 (Bean构造函数前) Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) //实例化Bean之后调用 boolean postProcessAfterInstantiation(Object bean, String beanName) PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) BeanPostProcessor //实例化、依赖注入完毕,在初始化之前调用,完成一些定制的初始化任务 Object postProcessBeforeInitialization(Object bean, String beanName) //实例化、依赖注入、初始化完毕时执行 Object postProcessAfterInitialization(Object bean, String beanName)
BeanFactoryPostProcessor和BeanPostProcessor都是Spring初始化bean的扩展点。两个接口非常相似。
BeanFactoryPostProcessor可以在postProcessBeanFactory()中对bean的定义(配置元数据)进行处理,而BeanPostProcessor不可以。
同时BeanFactoryPostProcessor的回调比BeanPostProcessor要早。
http://blog.csdn.net/mn11201117/article/details/24986325
http://blog.csdn.net/xiao_jun_0820/article/details/7242379
实例1:
百度文库:
实例2(重要):
Bean的完整生命周期经历了各种方法调用,这些方法可以划分为以下几类:
1、Bean自身的方法:
这个包括了Bean本身调用的方法和通过配置文件中<bean>的init-method和destroy-method指定的方法
2、Bean级生命周期接口方法:
这个包括了BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这些接口的方法
3、容器级生命周期接口方法:
这个包括了InstantiationAwareBeanPostProcessor 和 BeanPostProcessor 这两个接口实现,一般称它们的实现类为“后处理器”。
4、工厂后处理器接口方法:
这个包括了AspectJWeavingEnabler, ConfigurationClassPostProcessor, CustomAutowireConfigurer等等非常有用的工厂后处理器 接口的方法。工厂后处理器也是容器级的。在应用上下文装配配置文件之后立即调用。
我们用一个简单的Spring Bean来演示一下Spring Bean的生命周期。
1、首先是一个简单的Spring Bean,调用Bean自身的方法和Bean级生命周期接口方法,
为了方便演示,它实现了BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这4个接口,
【对于BeanFactoryAware和BeanNameAware接口,第一个接口让bean感知容器(即BeanFactory实例,从而以此获取该容器配置的其他bean对象),而后者让bean获得配置文件中对应的配置名称。在一般情况下用户不需要关心这两个接口。如果bean希望获得容器中的其他bean,可以通过属性注入的方式引用这些bean。如果bean希望在运行期获知在配置文件中的Bean名称,可以简单的将名称作为属性注入
综上所述,我们认为除非编写一个基于spring之上的扩展框架插件或者子项目之类的东西,否则用户完全可以抛开以上4个bean生命周期的接口类
但BeanPostProcessor接口却不一样,它不要求bean去继承它,它可以完全像插件一样注册到spring容器中,为容器提供额外的功能。spring充分利用了BeanPostProcessor对bean进行加工处理(SpringAOP以此为基础)】
同时有2个方法,对应配置文件中<bean>的init-method和destroy-method。如下:
package springBeanTest; import org.springframework.beans.BeansException; import org.springframework.beans.factory.BeanFactory; import org.springframework.beans.factory.BeanFactoryAware; import org.springframework.beans.factory.BeanNameAware; import org.springframework.beans.factory.DisposableBean; import org.springframework.beans.factory.InitializingBean; public class Person implements BeanFactoryAware, BeanNameAware, InitializingBean, DisposableBean { private String name; private String address; private int phone; private BeanFactory beanFactory; private String beanName; public Person() { System.out.println("【构造器】调用Person的构造器实例化"); } public String getName() { return name; } public void setName(String name) { System.out.println("【注入属性】注入属性name"); this.name = name; } public String getAddress() { return address; } public void setAddress(String address) { System.out.println("【注入属性】注入属性address"); this.address = address; } public int getPhone() { return phone; } public void setPhone(int phone) { System.out.println("【注入属性】注入属性phone"); this.phone = phone; } @Override public String toString() { return "Person [address=" + address + ", name=" + name + ", phone=" + phone + "]"; } // 这是BeanFactoryAware接口方法 @Override public void setBeanFactory(BeanFactory arg) throws BeansException { System.out .println("【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()"); this.beanFactory = arg; } // 这是BeanNameAware接口方法 @Override public void setBeanName(String arg) { System.out.println("【BeanNameAware接口】调用BeanNameAware.setBeanName()"); this.beanName = arg; } // 这是InitializingBean接口方法 @Override public void afterPropertiesSet() throws Exception { System.out .println("【InitializingBean接口】调用InitializingBean.afterPropertiesSet()"); } // 这是DiposibleBean接口方法 @Override public void destroy() throws Exception { System.out.println("【DiposibleBean接口】调用DiposibleBean.destory()"); } // 通过<bean>的init-method属性指定的初始化方法 public void myInit() { System.out.println("【init-method】调用<bean>的init-method属性指定的初始化方法"); } // 通过<bean>的destroy-method属性指定的初始化方法 public void myDestory() { System.out.println("【destroy-method】调用<bean>的destroy-method属性指定的初始化方法"); } }
2、接下来是演示BeanPostProcessor接口的方法,如下:
package springBeanTest; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanPostProcessor; public class MyBeanPostProcessor implements BeanPostProcessor { public MyBeanPostProcessor() { super(); System.out.println("这是BeanPostProcessor实现类构造器!!"); } @Override public Object postProcessAfterInitialization(Object arg, String arg) throws BeansException { System.out.println("BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改!"); return arg; } @Override public Object postProcessBeforeInitialization(Object arg, String arg) throws BeansException { System.out.println("BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改!"); return arg; } }
如上,BeanPostProcessor接口包括2个方法postProcessAfterInitialization和postProcessBeforeInitialization,这两个方法的第一个参数都是要处理的Bean对象,第二个参数都是Bean的name。返回值也都是要处理的Bean对象。这里要注意。
3、InstantiationAwareBeanPostProcessor 接口本质是BeanPostProcessor的子接口,一般我们继承Spring为其提供的适配器类InstantiationAwareBeanPostProcessorAdapter来使用它,如下:
package springBeanTest; import java.beans.PropertyDescriptor; import org.springframework.beans.BeansException; import org.springframework.beans.PropertyValues; import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter; public class MyInstantiationAwareBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter { public MyInstantiationAwareBeanPostProcessor() { super(); System.out.println("这是InstantiationAwareBeanPostProcessorAdapter实现类构造器!!"); } // 接口方法、实例化Bean之前调用 @Override public Object postProcessBeforeInstantiation(Class beanClass, String beanName) throws BeansException { System.out.println("InstantiationAwareBeanPostProcessor调用postProcessBeforeInstantiation方法"); return null; } // 接口方法、实例化Bean之后调用 @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { System.out.println("InstantiationAwareBeanPostProcessor调用postProcessAfterInitialization方法"); return bean; } // 接口方法、设置某个属性时调用 @Override public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException { System.out.println("InstantiationAwareBeanPostProcessor调用postProcessPropertyValues方法"); return pvs; } }
这个有3个方法,其中第二个方法postProcessAfterInitialization就是重写了BeanPostProcessor的方法。第三个方法postProcessPropertyValues用来操作属性,返回值也应该是PropertyValues对象。
4、演示工厂后处理器接口方法,如下:
package springBeanTest; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.BeanDefinition; import org.springframework.beans.factory.config.BeanFactoryPostProcessor; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor { public MyBeanFactoryPostProcessor() { super(); System.out.println("这是BeanFactoryPostProcessor实现类构造器!!"); } @Override public void postProcessBeanFactory(ConfigurableListableBeanFactory arg) throws BeansException { System.out .println("BeanFactoryPostProcessor调用postProcessBeanFactory方法"); BeanDefinition bd = arg.getBeanDefinition("person"); bd.getPropertyValues().addPropertyValue("phone", ""); } }
5、配置文件如下beans.xml,很简单,使用ApplicationContext,处理器不用手动注册:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd"> <bean id="beanPostProcessor" class="springBeanTest.MyBeanPostProcessor"></bean> <bean id="instantiationAwareBeanPostProcessor" class="springBeanTest.MyInstantiationAwareBeanPostProcessor"></bean> <bean id="beanFactoryPostProcessor" class="springBeanTest.MyBeanFactoryPostProcessor"> </bean> <bean id="person" class="springBeanTest.Person" init-method="myInit" destroy-method="myDestory" scope="singleton" p:name="张三" p:address="广州" p:phone="15900000000" /> </beans>
6.测试
package springBeanTest; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class BeanLifeCycle { public static void main(String[] args) { System.out.println("现在开始初始化容器"); ApplicationContext ctx = new ClassPathXmlApplicationContext("springBeanTest/beans.xml"); System.out.println("容器初始化成功"); //得到Preson,并使用 Person person = ctx.getBean("person",Person.class); System.out.println(person); System.out.println("现在开始关闭容器!"); ((ClassPathXmlApplicationContext)ctx).registerShutdownHook(); } }
结果如下:
现在开始初始化容器
2014-5-18 15:46:20 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@19a0c7c: startup date [Sun May 18 15:46:20 CST 2014]; root of context hierarchy
2014-5-18 15:46:20 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [springBeanTest/beans.xml]
这是BeanFactoryPostProcessor实现类构造器!
BeanFactoryPostProcessor调用postProcessBeanFactory方法
这是BeanPostProcessor实现类构造器!!
这是InstantiationAwareBeanPostProcessorAdapter实现类构造器!!
2014-5-18 15:46:20 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@9934d4: defining beans [beanPostProcessor,instantiationAwareBeanPostProcessor,beanFactoryPostProcessor,person]; root of factory hierarchy
InstantiationAwareBeanPostProcessor调用postProcessBeforeInstantiation方法
【构造器】调用Person的构造器实例化
InstantiationAwareBeanPostProcessor调用postProcessPropertyValues方法
【注入属性】注入属性address
【注入属性】注入属性name
【注入属性】注入属性phone
【BeanNameAware接口】调用BeanNameAware.setBeanName()
【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()
BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改!
【InitializingBean接口】调用InitializingBean.afterPropertiesSet()
【init-method】调用<bean>的init-method属性指定的初始化方法
BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改!
InstantiationAwareBeanPostProcessor调用postProcessAfterInitialization方法(这个位置感觉有问题,待解决)
容器初始化成功
Person [address=广州, name=张三, phone=110]
现在开始关闭容器!
【DiposibleBean接口】调用DiposibleBean.destory()
【destroy-method】调用<bean>的destroy-method属性指定的初始化方法
图示如下: