BeanPostProcessor相关接口执行的方法

1. BeanPostProcessor相关接口

• InstantiationAwareBeanPostProcessor
• DestructionAwareBeanPostProcessor
• MergedBeanDefinitionPostProcessor
• SmartInstantiationAwareBeanPostProcessor

四个继承接口加上 BeanPostProcessor 一共五个接口。看一下这五个接口的方法：

public interface BeanPostProcessor {
	@Nullable
	default Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		return bean;
	}
		@Nullable
	default Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
		return bean;
	}

}

InstantiationAwareBeanPostProcessor 、 DestructionAwareBeanPostProcessor、 MergedBeanDefinitionPostProcessor 继承了 BeanPostProcessor ：

public interface InstantiationAwareBeanPostProcessor extends BeanPostProcessor {
    @Nullable
	default Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
		return null;
	}
	default boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
		return true;
	}
	//@since 5.1
	@Nullable
	default PropertyValues postProcessProperties(PropertyValues pvs, Object bean, String beanName)
			throws BeansException {

		return null;
	}
}

public interface DestructionAwareBeanPostProcessor extends BeanPostProcessor {
    void postProcessBeforeDestruction(Object bean, String beanName) throws BeansException;

    default boolean requiresDestruction(Object bean) {
		return true;
	}
}

public interface MergedBeanDefinitionPostProcessor extends BeanPostProcessor {
	void postProcessMergedBeanDefinition(RootBeanDefinition beanDefinition, Class<?> beanType, String beanName);
	
		default void resetBeanDefinition(String beanName) {
	}
}

SmartInstantiationAwareBeanPostProcessor 继承了 InstantiationAwareBeanPostProcessor 接口。

public interface SmartInstantiationAwareBeanPostProcessor extends InstantiationAwareBeanPostProcessor {
	@Nullable
	default Class<?> predictBeanType(Class<?> beanClass, String beanName) throws BeansException {
		return null;
	}
	@Nullable
	default Constructor<?>[] determineCandidateConstructors(Class<?> beanClass, String beanName)
			throws BeansException {

		return null;
	}
	default Object getEarlyBeanReference(Object bean, String beanName) throws BeansException {
		return bean;
	}
}

2. BeanPostProcessor相关接口执行顺序

1. InstantiationAwareBeanPostProcessor#postProcessBeforeInstantiation
2. MergedBeanDefinitionPostProcessor#postProcessMergedBeanDefinition
3. SmartInstantiationAwareBeanPostProcessor#getEarlyBeanReference
4. InstantiationAwareBeanPostProcessor#postProcessAfterInstantiation
5. InstantiationAwareBeanPostProcessor#postProcessProperties
6. BeanPostProcessor#postProcessBeforeInitialization
7. BeanPostProcessor#postProcessAfterInitialization
8. DestructionAwareBeanPostProcessor#requiresDestruction
9. DestructionAwareBeanPostProcessor#postProcessBeforeDestruction