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BeanFactoryPostProcessor ->postProcessBeanFactory()
InstantiationAwareBeanPostProcessor ->postProcessPropertyValues()
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)
这个包括了Bean本身调用的方法和通过配置文件中的init-method和destroy-method指定的方法
这个包括了BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这些接口的方法
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”。
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。
为了方便演示,它实现了BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这4个接口,同时有2个方法,对应配置文件中的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()"); } // 通过的init-method属性指定的初始化方法 public void myInit() { System.out.println("【init-method】调用 的init-method属性指定的初始化方法"); } // 通过 的destroy-method属性指定的初始化方法 public void myDestory() { System.out.println("【destroy-method】调用 的destroy-method属性指定的初始化方法"); } }
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)。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。
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。
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", ""); } }
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 hierarchyInstantiationAwareBeanPostProcessor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】调用的destroy-method属性指定的初始化方法转载地址:http://ksgmi.baihongyu.com/