Spring源码解析 (后置处理器的实现与实现的顺序)

文章目录

• • • 1.概述
    • 2.测试
    • 3.后置处理器的实现的顺序

1.概述

生命周期后置处理器: BeanPostProcessor, BeanFactoryPostProcessor

生命周期后置处理： InitializingBean, DisposableBean

后置处理器会传入bean, 在于改变, 而InitialzingBean在于额外处理

2.测试

这里通过实现类实现他们

BeanPostProcessor

@Component
public class MyBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("MyBeanPostProcessor postProcessBeforeInitialization");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("MyBeanPostProcessor postProcessAfterInitialization");
        return bean;
    }
}

InstantiationAwareBeanPostProcessor

@Component
public class MyInstantiationAwareBeanPostProcessor implements InstantiationAwareBeanPostProcessor {
    @Override
    public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
        System.out.println("MyInstantiationAwareBeanPostProcessor postProcessBeforeInstantiation");
        return null;
    }

    @Override
    public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
        System.out.println("MyInstantiationAwareBeanPostProcessor postProcessAfterInstantiation");
        return true;
    }

    @Override
    public PropertyValues postProcessProperties(PropertyValues pvs, Object bean, String beanName) throws BeansException {
        System.out.println("MyInstantiationAwareBeanPostProcessor postProcessProperties");
        return null;
    }
}

MergedBeanDefinitionPostProcessor

@Component
public class MyMergedBeanDefinitionPostProcessor implements MergedBeanDefinitionPostProcessor {
    @Override
    public void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class<?> beanType, String beanName) {
        System.out.println("MergedBeanDefinitionPostProcessor postProcessMergedBeanDefinition");
    }

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("MyMergedBeanDefinitionPostProcessor postProcessBeforeInitialization" + beanName);
        return null;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("MyMergedBeanDefinitionPostProcessor postProcessAfterInitialization" + beanName);
        return null;
    }
}

SmartInstantiationAwareBeanPostProcessor

@Component
public class MySmartInstantiationAwareBeanPostProcessor implements SmartInstantiationAwareBeanPostProcessor {
    @Override
    public Class<?> predictBeanType(Class<?> beanClass, String beanName) throws BeansException {
        System.out.println("MySmartInstantiationAwareBeanPostProcessor predictBeanType");
        return null;
    }

    @Override
    public Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName) throws BeansException {
        System.out.println("MySmartInstantiationAwareBeanPostProcessor determineCandidateConstructors");
        return null;
    }

    @Override
    public Object getEarlyBeanReference(Object bean, String beanName) throws BeansException {
        System.out.println("MySmartInstantiationAwareBeanPostProcessor getEarlyBeanReference");
        return bean;
    }
}

BeanFactoryPostProcessor

@Component
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("MyBeanFactoryPostProcessor postProcessBeanFactory");
    }

}

BeanDefinitionRegistryPostProcessor

@Component
public class MyBeanDefinitionRegistryPostProcessor implements BeanDefinitionRegistryPostProcessor {
    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        System.out.println("MyBeanDefinitionRegistryPostProcessor postProcessBeanDefinitionRegistry");
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("MyBeanDefinitionRegistryPostProcessor postProcessBeanFactory");
    }
}

InitializingBean

@Component
public class MyInitializingBean implements InitializingBean {
    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("MyInitializingBean afterPropertiesSet");
    }
}

运行的顺序为

MyBeanDefinitionRegistryPostProcessor postProcessBeanDefinitionRegistry
MyBeanDefinitionRegistryPostProcessor postProcessBeanFactory
MyBeanFactoryPostProcessor postProcessBeanFactory
MySmartInstantiationAwareBeanPostProcessor predictBeanType
MyInstantiationAwareBeanPostProcessor postProcessBeforeInstantiation
MySmartInstantiationAwareBeanPostProcessor determineCandidateConstructors
MergedBeanDefinitionPostProcessor postProcessMergedBeanDefinition
MyInstantiationAwareBeanPostProcessor postProcessAfterInstantiation
MyInstantiationAwareBeanPostProcessor postProcessProperties
MyBeanPostProcessor postProcessBeforeInitialization
MyMergedBeanDefinitionPostProcessor postProcessBeforeInitializationmainConfig
MyInitializingBean afterPropertiesSet
MyBeanPostProcessor postProcessAfterInitialization
MyMergedBeanDefinitionPostProcessor postProcessAfterInitializationmainConfig

3.后置处理器的实现的顺序