Spring源码情操陶冶-AbstractApplicationContext#registerBeanPostProcessors

承接前文Spring源码情操陶冶-AbstractApplicationContext#invokeBeanFactoryPostProcessors

瞧瞧官方注释

	/**
	 * Instantiate and invoke all registered BeanPostProcessor beans,
	 * respecting explicit order if given.
	 * <p>Must be called before any instantiation of application beans.
	 */

实例化并且调用所有的已注册的BeanPostProcessor beans，其实也就是简单的把DefaultListableFactory中的所有为BeanPostProcessor的实现bean类放置于其内部属性beanPostProcessors List集合中。

直接源码

protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
    //调用的是委托类的registerBeanPostProcessors方法		
    PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
	}

间接源码-PostProcessorRegistrationDelegate.registerBeanPostProcessors

public static void registerBeanPostProcessors(
			ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
//获取beanFactory中的所有实现BeanPostProcessor接口的bean
		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;
		//BeanPostProcessorChecker检查类
		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

		//此处的实现与上节的invokeBeanFactoryPostProcessors方法一致，这里就省略不赘述了
		List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanPostProcessor>();
		List<BeanPostProcessor> internalPostProcessors = new ArrayList<BeanPostProcessor>();
		List<String> orderedPostProcessorNames = new ArrayList<String>();
		List<String> nonOrderedPostProcessorNames = new ArrayList<String>();
		/**省略*/

		// Finally, re-register all internal BeanPostProcessors.
		OrderComparator.sort(internalPostProcessors);
		//主要是调用此方法将所有的postProcessors按照优先级有序的放置在beanFactory的内部属性beanPostProcessors集合中
		registerBeanPostProcessors(beanFactory, internalPostProcessors);
		//增加ApplicationListenerDetector类
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
	}

小结

1. 获取beanFactory中的所有实现postProcessor接口的bean对象按照优先级有序的放置在beanFactory的内部属性beanPostProcessors集合中，但是并没有执行其中的相应公共方法
2. 新增两个BeanPostProcessor实现类：BeanPostProcessorChecker为首，ApplicationListenerDetector为尾

下节预告

Spring源码情操陶冶-AbstractApplicationContext#initMessageSource