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Spring bean生命周期中的钩子

Spring bean生命周期中的钩子

作者: 捉虫大师 | 来源:发表于2018-08-04 19:33 被阅读154次

    bean自身级生命周期接口

    • 配置文件中的init-method和destroy-method方法
    • bean实现BeanNameAware、BeanFactoryAware、InitializingBean和DiposableBean这些接口的方法

    做个实验看一下这些方法的调用顺序

    先是两个bean

    package autopackage;
    
    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 Fruit fruit;
    
        private String name;
    
        public Person(String name, Fruit fruit) {
            System.out.println("I'm the Person1");
            this.name = name;
            this.fruit = fruit;
        }
    
        public Person(Fruit fruit) {
            System.out.println("I'm the Person2");
            this.fruit = fruit;
        }
    
        public void setFruit(Fruit fruit) {
            System.out.println("I'm the setFruit");
    
            this.fruit = fruit;
        }
    
        public void setName(String name) {
            System.out.println("I'm the setName");
    
            this.name = name;
        }
    
        public void init() {
            System.out.println("I'm the init");
        }
    
        public void destroy1() {
            System.out.println("I'm the destroy1");
        }
    
        public void eat() {
            System.out.println(name+"正在吃"+fruit.getName()+"...");
        }
    
        @Override
        public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
            System.out.println("I'm the BeanFactoryAware.setBeanFactory");
        }
    
        @Override
        public void setBeanName(String s) {
            System.out.println("I'm the BeanNameAware.setBeanName");
        }
    
        @Override
        public void afterPropertiesSet() throws Exception {
            System.out.println("I'm the InitializingBean.afterPropertiesSet");
        }
    
        @Override
        public void destroy() {
            System.out.println("I'm the DisposableBean.destroy");
        }
    
    
    }
    
    package autopackage;
    
    public class Fruit {
        private String name;
    
        public Fruit(String name) {
            this.name = name;
        }
    
        public String getName() {
            return name;
        }
    }
    
    

    接着是xml配置文件

    <?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" class="autopackage.Person" init-method="init" destroy-method="destroy1">
            <!--<constructor-arg value="lkxiaolou" />-->
            <constructor-arg ref="fruit" />
            <property name="name" value="lkxiaolou"/>
        </bean>
    
        <bean id="fruit" class="autopackage.Fruit">
            <constructor-arg value="apple" />
        </bean>
    
    </beans>
    

    再是测试代码

    package main;
    
    import autopackage.Person;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class PersonMain {
    
        public static void main(String[] args) {
            ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("Person.xml");
            Person person = (Person) context.getBean("person");
            person.eat();
            context.registerShutdownHook();
        }
    }
    

    执行后会发现输出是这样的:

    I'm the Person2
    I'm the setName
    I'm the BeanNameAware.setBeanName
    I'm the BeanFactoryAware.setBeanFactory
    I'm the InitializingBean.afterPropertiesSet
    I'm the init
    lkxiaolou正在吃apple...
    I'm the DisposableBean.destroy
    I'm the destroy1
    

    容器级生命周期接口方法

    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”,InstantiationAwareBeanPostProcessor 接口本质是BeanPostProcessor的子接口,我们继承Spring为其提供的适配器类InstantiationAwareBeanPostProcessor Adapter来使用它。

    将上面的代码改造一下,新建一个新类

    package autopackage;
    
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
    import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
    
    
    public class PersonBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
    
        public PersonBeanFactoryPostProcessor() {
            System.out.println("I'm the PersonBeanFactoryPostProcessor");
        }
    
        @Override
        public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
            System.out.println("I'm the PersonBeanFactoryPostProcessor.postProcessBeanFactory");
        }
    }
    
    
    package autopackage;
    
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.config.BeanPostProcessor;
    
    public class PersonBeanPostProcessor implements BeanPostProcessor {
    
        public PersonBeanPostProcessor() {
            System.out.println("I'm the PersonBeanPostProcessor");
        }
    
        @Override
        public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person) {
                System.out.println("I'm the PersonBeanPostProcessor.postProcessBeforeInitialization;beanName=" + beanName);
            }
            return bean;
        }
    
        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person) {
                System.out.println("I'm the PersonBeanPostProcessor.postProcessAfterInitialization;beanName=" + beanName);
            }
            return bean;
        }
    }
    
    
    package autopackage;
    
    import org.springframework.beans.BeansException;
    import org.springframework.beans.PropertyValues;
    import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
    
    import java.beans.PropertyDescriptor;
    import java.lang.reflect.Constructor;
    
    public class PersonInstantiationAwareBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter {
    
        public PersonInstantiationAwareBeanPostProcessor() {
            super();
            System.out.println("I'm the PersonInstantiationAwareBeanPostProcessor");
        }
    
        @Override
        public Class<?> predictBeanType(Class<?> beanClass, String beanName) {
            return super.predictBeanType(beanClass, beanName);
        }
    
        @Override
        public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName) throws BeansException {
            return super.determineCandidateConstructors(beanClass, beanName);
        }
    
        @Override
        public Object getEarlyBeanReference(Object bean, String beanName) throws BeansException {
            return super.getEarlyBeanReference(bean, beanName);
        }
    
        @Override
        public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
            if (beanClass.equals(Person.class)) {
                System.out.println("I'm the PersonInstantiationAwareBeanPostProcessor.postProcessBeforeInstantiation");
            }
            return super.postProcessBeforeInstantiation(beanClass, beanName);
        }
    
        @Override
        public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person) {
                System.out.println("I'm the PersonInstantiationAwareBeanPostProcessor.postProcessAfterInstantiation");
            }
            return super.postProcessAfterInstantiation(bean, beanName);
        }
    
        @Override
        public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeansException {
            if (bean instanceof Person) {
                System.out.println("I'm the PersonInstantiationAwareBeanPostProcessor.postProcessPropertyValues");
            }
            return super.postProcessPropertyValues(pvs, pds, bean, beanName);
        }
    
        @Override
        public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person) {
                System.out.println("I'm the PersonInstantiationAwareBeanPostProcessor.postProcessBeforeInitialization");
            }
    
            return super.postProcessBeforeInitialization(bean, beanName);
        }
    
        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            if (bean instanceof Person) {
                System.out.println("I'm the PersonInstantiationAwareBeanPostProcessor.postProcessAfterInitialization");
            }
            return super.postProcessAfterInitialization(bean, beanName);
        }
    }
    
    

    xml修改一下

    <?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" class="autopackage.Person" init-method="init" destroy-method="destroy1">
            <!--<constructor-arg value="lkxiaolou" />-->
            <constructor-arg ref="fruit" />
            <property name="name" value="lkxiaolou"/>
        </bean>
    
        <bean id="fruit" class="autopackage.Fruit">
            <constructor-arg value="apple" />
        </bean>
    
        <bean id="instantiationAwareBeanPostProcessor" class="autopackage.PersonInstantiationAwareBeanPostProcessor"></bean>
        <bean id="beanPostProcessor" class="autopackage.PersonBeanPostProcessor"></bean>
        <bean id="beanFactoryPostProcessor" class="autopackage.PersonBeanFactoryPostProcessor"></bean>
    
    </beans>
    
    
    

    其他不变,再执行一下输出如下

    I'm the PersonBeanFactoryPostProcessor
    I'm the PersonBeanFactoryPostProcessor.postProcessBeanFactory
    I'm the PersonInstantiationAwareBeanPostProcessor
    I'm the PersonBeanPostProcessor
    I'm the PersonInstantiationAwareBeanPostProcessor.postProcessBeforeInstantiation
    I'm the Person2
    I'm the PersonInstantiationAwareBeanPostProcessor.postProcessAfterInstantiation
    I'm the PersonInstantiationAwareBeanPostProcessor.postProcessPropertyValues
    I'm the setName
    I'm the BeanNameAware.setBeanName
    I'm the BeanFactoryAware.setBeanFactory
    I'm the PersonInstantiationAwareBeanPostProcessor.postProcessBeforeInitialization
    I'm the PersonBeanPostProcessor.postProcessBeforeInitialization;beanName=person
    I'm the InitializingBean.afterPropertiesSet
    I'm the init
    I'm the PersonInstantiationAwareBeanPostProcessor.postProcessAfterInitialization
    I'm the PersonBeanPostProcessor.postProcessAfterInitialization;beanName=person
    lkxiaolou正在吃apple...
    I'm the DisposableBean.destroy
    I'm the destroy1
    

    总结

    可以总结出整个bean的生命周期中各个钩子执行的顺序:


    bean声明周期中钩子运行顺序.jpg

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