Spring - BeanNameAware扩展接口

Posted 2022-12-15 小小工匠

文章目录

• Pre
• org.springframework.beans.factory.BeanNameAware
• 触发点&使用场景
• 源码分析
• 扩展示例

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Pre

Spring Boot - 扩展接口一览

Spring - BeanFactoryAware扩展接口

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org.springframework.beans.factory.BeanNameAware

public interface BeanNameAware extends Aware 

	/**
	 * Set the name of the bean in the bean factory that created this bean.
	 * <p>Invoked after population of normal bean properties but before an
	 * init callback such as @link InitializingBean#afterPropertiesSet()
	 * or a custom init-method.
	 * @param name the name of the bean in the factory.
	 * Note that this name is the actual bean name used in the factory, which may
	 * differ from the originally specified name: in particular for inner bean
	 * names, the actual bean name might have been made unique through appending
	 * "#..." suffixes. Use the @link BeanFactoryUtils#originalBeanName(String)
	 * method to extract the original bean name (without suffix), if desired.
	 */
	void setBeanName(String name);

触发点&使用场景

触发点在bean的初始化之前，也就是postProcessBeforeInitialization之前，这个类的触发点方法只有一个：setBeanName

使用场景为：用户可以扩展这个点，在初始化bean之前拿到spring容器中注册的的beanName，来自行修改这个beanName的值。

源码分析

org.springframework.context.support.PostProcessorRegistrationDelegate#registerBeanPostProcessors()
	BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
		org.springframework.beans.factory.support.AbstractBeanFactory#getBean
		  org.springframework.beans.factory.support.AbstractBeanFactory#doGetBean	
			  org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#createBean
					org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#doCreateBean
						 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#initializeBean 
							org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#invokeAwareMethods

	private void invokeAwareMethods(String beanName, Object bean) 
		if (bean instanceof Aware) 
			if (bean instanceof BeanNameAware) 
				((BeanNameAware) bean).setBeanName(beanName);
			
			if (bean instanceof BeanClassLoaderAware) 
				ClassLoader bcl = getBeanClassLoader();
				if (bcl != null) 
					((BeanClassLoaderAware) bean).setBeanClassLoader(bcl);
				
			
			if (bean instanceof BeanFactoryAware) 
				((BeanFactoryAware) bean).setBeanFactory(AbstractAutowireCapableBeanFactory.this);
			
		
	

扩展示例

比较简单，随便写一个吧

public class ArtisanBean  implements BeanNameAware
    public ArtisanBean  () 
        System.out.println("ArtisanBean  init");
    

    @Override
    public void setBeanName(String name) 
        System.out.println("[BeanNameAware] " + name);