spring AbstractApplicationContext.regilsterBeanPostProcessors

最新推荐文章于 2022-07-14 19:29:59 发布

xuyunti

最新推荐文章于 2022-07-14 19:29:59 发布

阅读量148

点赞数

CC 4.0 BY-SA版权

分类专栏： spring 文章标签： java

本文链接：https://blog.youkuaiyun.com/xuyunti/article/details/84743655

spring 专栏收录该内容

27 篇文章

订阅专栏

本文深入探讨Spring中BeanPostProcessor的作用与实现机制，包括其接口定义、注册流程及内部处理逻辑，阐述如何利用BeanPostProcessor扩展Spring的功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

 
regilsterBeanPostProcessors 方法也是在容器初始化时调用，主要是注册BeanPostProcessor。
BeanPostProcessor 在spring中扮演了重要的角色它提供了扩展spring的可能。如Aop,spring事物都是基于BeanPostProcessor ，BeanPostProcessor 作用就是再生成Bean时对bean进行加强处理如生成代理对象。。
public interface BeanPostProcessor {

	//bean初始化前
	Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;
      //bean初始化后
       Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;

}

protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
		String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);

		// Register BeanPostProcessorChecker that logs an info message when
		// a bean is created during BeanPostProcessor instantiation, i.e. when
		// a bean is not eligible for getting processed by all BeanPostProcessors.
		int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

		// Separate between BeanPostProcessors that implement PriorityOrdered,
		// Ordered, and the rest.
		List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
		List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>();
		List<String> orderedPostProcessorNames = new ArrayList<String>();
		List<String> nonOrderedPostProcessorNames = new ArrayList<String>();
		for (String ppName : postProcessorNames) {
			if (isTypeMatch(ppName, PriorityOrdered.class)) {
				BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
				priorityOrderedPostProcessors.add(pp);
				if (pp instanceof MergedBeanDefinitionPostProcessor) {
					internalPostProcessors.add(pp);
				}
			}
			else if (isTypeMatch(ppName, Ordered.class)) {
				orderedPostProcessorNames.add(ppName);
			}
			else {
				nonOrderedPostProcessorNames.add(ppName);
			}
		}

		// First, register the BeanPostProcessors that implement PriorityOrdered.
		OrderComparator.sort(priorityOrderedPostProcessors);
		registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

		// Next, register the BeanPostProcessors that implement Ordered.
		List<BeanPostProcessor> orderedPostProcessors = new ArrayList<BeanPostProcessor>();
		for (String ppName : orderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			orderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				internalPostProcessors.add(pp);
			}
		}
		OrderComparator.sort(orderedPostProcessors);
		registerBeanPostProcessors(beanFactory, orderedPostProcessors);

		// Now, register all regular BeanPostProcessors.
		List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
		for (String ppName : nonOrderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			nonOrderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				internalPostProcessors.add(pp);
			}
		}
		registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);

		// Finally, re-register all internal BeanPostProcessors.
		OrderComparator.sort(internalPostProcessors);
		registerBeanPostProcessors(beanFactory, internalPostProcessors);
 //添加处理实现了ApplicationListener接口类，放入applicationEventMulticaster中
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector());
	}