Spring ApplicationContext容器的Bean的生命周期有13步,而后三步容器关闭和实现接口的destroy()方法和自定义的销毁方法是不可见的。
在前九步【new ClassPathXmlApplicationContext("xx.xml"),加载容器装配bean】,每个bean对象的生命周期是并列的,按照beans.xml配置文件的配置顺序,先完成一个bean的九步,然后是下一个bean对象的九步。而第十步使用bean 【getBean("id")】bean对象都完成9步才会调用。
以下是部分代码
Person和Employee类
package top.chgl16.myspring.beanlife; 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; import org.springframework.beans.factory.config.BeanPostProcessor; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; /** * * @Lin 2018-5-15 * 测试全部周期的一个bean * */ public class Person implements BeanNameAware, BeanFactoryAware, ApplicationContextAware, InitializingBean, DisposableBean { public String name; public String getName() { return name; } public void setName(String name) { this.name = name; System.out.println("bean生命周期第二步, 属性注入,setXxx()方法"); } public Person() { System.out.println("bean生命周期第一步, 实例化对象,调用了Person的构造函数"); } public void setBeanName(String arg0) { // bean生命周期第三步,BeanNameAware接口,实现其setBeanName方法, arg0是Bean的name/id System.out.println("bean生命周期第三步,BeanNameAware接口,实现其setBeanName方法 arg0: " + arg0); } public void setBeanFactory(BeanFactory arg0) throws BeansException { // bean生命周期第四步,BeanFactoryAware接口,实现其setBeanFactory方法, arg0是BeanFactory对象 System.out.println("bean生命周期第四步,BeanFactoryAware接口,实现其setBeanFactory方法, arg0: " + arg0); } public void setApplicationContext(ApplicationContext arg0) throws BeansException { // bean生命周期第五步,ApplicationContextAware接口,实现其setApplicationContext方法, arg0是ApplicationContext对象 System.out.println("bean生命周期第五步,ApplicationContextAware接口,实现其setApplicationContext方法, arg0: " + arg0); } /* public Object postProcessAfterInitialization(Object arg0, String arg1) throws BeansException { // TODO Auto-generated method stub System.out.println("postProcessAfterInitialization"); return null; } public Object postProcessBeforeInitialization(Object arg0, String arg1) throws BeansException { // TODO Auto-generated method stub System.out.println("postProcessBeforeInitialization"); return null; } */ public void init() { System.out.println("bean生命周期第八步,自定义的初始化方法,在配置中 init-method=\"init\""); } public void afterPropertiesSet() throws Exception { // 不具备AOP System.out.println("bean生命周期第七步,InitializingBean 接口"); } public void destroy() throws Exception { // 可以关闭数据连接,等。。但是看不到显示,定制的方法可以显示 System.out.println("bean生命周期第十二步,调用DisposableBean接口的destroy()方法"); } // 定制的销毁方法 public void myDestroy() { // 自定义的销毁方法,也是看不到的 最后一步 System.out.println("bean生命周期第十三步,调用自定义的方法 ,在配置中 destroy-method=\\\"myDestroy\\\""); } }
package top.chgl16.myspring.beanlife; /** * * @Lin 2018-5-15 * 为了测试的草稿bean类 * */ public class Employee { public String name; public String getName() { return name; } public void setName(String name) { this.name = name; } public Employee() { System.out.println("bean生命周期第一步, 实例化对象,调用了Employee的构造函数"); } }
具有AOP特殊的BeanPostProcessor
package top.chgl16.myspring.beanlife; import org.springframework.beans.BeansException; import org.springframework.beans.factory.InitializingBean; import org.springframework.beans.factory.config.BeanPostProcessor; /** * @Lin 2018-5-15 * 这是另外新建的一个类,来实现BeanPostProcessor接口,Before和After方法具有AOP特性,所以如此关联建立 * afterPropertiesSet()方法是InitializingBean接口的,周期中排在Before后面,全局比较奇怪,姑还是在相应的Bean类里实现为好 * 这个类也要配置为Bean */ public class MyBeanPostProcessor implements BeanPostProcessor, InitializingBean { public Object postProcessAfterInitialization(Object arg0, String arg1) throws BeansException { System.out.println("bean生命周期第九步,postProcessAfterInitialization 被调用 arg1:" + arg0); System.out.println("\n"); return arg0; // before和after都要放回 arg0或者对象,弄人 return null, 马上空指针异常 } public Object postProcessBeforeInitialization(Object arg0, String arg1) throws BeansException { System.out.println("bean生命周期第六步,postProcessBeforeInitialization 被调用 arg1:" + arg1); return arg0; // before和after都要放回 arg0或者对象,弄人 return null, 马上空指针异常 } // 这里的这个方法不会被调用,没有aop功能 public void afterPropertiesSet() throws Exception { System.out.println("InitializingBean接口, 很奇怪在首先调用了,设置属性前"); } }
beans.xml
<?xml version="1.0" encoding="utf-8" ?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean id="person" scope="singleton" init-method="init" destroy-method="myDestroy" class="top.chgl16.myspring.beanlife.Person"> <property name="name" value="chgl16" ></property> <!-- spring中的类都叫bean,property是给类成员初始化 --> </bean> <bean id="employee" class="top.chgl16.myspring.beanlife.Employee"> <property name="name" value="小明员工" ></property> </bean> <bean id="myBeanPostProcessor" scope="prototype" class="top.chgl16.myspring.beanlife.MyBeanPostProcessor" > <!-- BeanPostProcessor具有AOP性质 --> </bean> <bean id="myBeanNameAware" class="top.chgl16.myspring.beanlife.MyBeanNameAware" > <!-- 测试BeanNameAware是否具有AOP性质,没有 --> </bean> </beans>
输出:
五月 17, 2018 5:43:45 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@433c675d: startup date [Thu May 17 17:43:45 CST 2018]; root of context hierarchy 五月 17, 2018 5:43:45 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [top/chgl16/myspring/beanlife/beans.xml] InitializingBean接口, 很奇怪在首先调用了,设置属性前 bean生命周期第一步, 实例化对象,调用了Person的构造函数 bean生命周期第二步, 属性注入,setXxx()方法 bean生命周期第三步,BeanNameAware接口,实现其setBeanName方法 arg0: person bean生命周期第四步,BeanFactoryAware接口,实现其setBeanFactory方法, arg0: org.springframework.beans.factory.support.DefaultListableBeanFactory@3567135c: defining beans [person,employee,myBeanPostProcessor,myBeanNameAware]; root of factory hierarchy bean生命周期第五步,ApplicationContextAware接口,实现其setApplicationContext方法, arg0: org.springframework.context.support.ClassPathXmlApplicationContext@433c675d: startup date [Thu May 17 17:43:45 CST 2018]; root of context hierarchy bean生命周期第六步,postProcessBeforeInitialization 被调用 arg1:person bean生命周期第七步,InitializingBean 接口 bean生命周期第八步,自定义的初始化方法,在配置中 init-method="init" bean生命周期第九步,postProcessAfterInitialization 被调用 arg1:top.chgl16.myspring.beanlife.Person@6500df86 bean生命周期第一步, 实例化对象,调用了Employee的构造函数 bean生命周期第六步,postProcessBeforeInitialization 被调用 arg1:employee bean生命周期第九步,postProcessAfterInitialization 被调用 arg1:top.chgl16.myspring.beanlife.Employee@4cf777e8 测试 MyBeanNameAware, 配置后被当做一个单独的bean而已 bean生命周期第六步,postProcessBeforeInitialization 被调用 arg1:myBeanNameAware bean生命周期第九步,postProcessAfterInitialization 被调用 arg1:top.chgl16.myspring.beanlife.MyBeanNameAware@2f686d1f bean生命周期第十步,Hello chgl16