Spring源码-10-容器refresh之registerBeanPostProcessors方法

// AbstractApplicationContext.java
/**
				 * 5 Bean实例化初始化之前将后置处理器注册到容器中
				 * 后置处理器的职责
				 *     - BeanDefinition都已经注册到了Bean工厂中(DefaultListableBeanFactory的beanDefinitionMap)
				 *     - Spring可以根据BeanDefinition进行Bean的实例化和初始化
				 *     - 在此之前注册Bean的后置处理器
				 *         - 在Bean实例化前后回调
				 *         - 在Bean初始化前后回调
				 * 上面Bean工厂后置处理器执行结束之后 就已经将BeanDefinition都注册到Bean工厂beanDefinitionMap中了
				 * 现在将所有Bean工厂中BeanDefinition中是Bean后置处理器的都进行实例化注册到Bean工厂的beanPostProcessors中
				 */
this.registerBeanPostProcessors(beanFactory);

// AbstractApplicationContext.java
protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
    PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
}

public static void registerBeanPostProcessors(
    ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {

    // WARNING: Although it may appear that the body of this method can be easily
    // refactored to avoid the use of multiple loops and multiple lists, the use
    // of multiple lists and multiple passes over the names of processors is
    // intentional. We must ensure that we honor the contracts for PriorityOrdered
    // and Ordered processors. Specifically, we must NOT cause processors to be
    // instantiated (via getBean() invocations) or registered in the ApplicationContext
    // in the wrong order.
    //
    // Before submitting a pull request (PR) to change this method, please review the
    // list of all declined PRs involving changes to PostProcessorRegistrationDelegate
    // to ensure that your proposal does not result in a breaking change:
    // https://github.com/spring-projects/spring-framework/issues?q=PostProcessorRegistrationDelegate+is%3Aclosed+label%3A%22status%3A+declined%22

    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<>();
    List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
    List<String> orderedPostProcessorNames = new ArrayList<>();
    List<String> nonOrderedPostProcessorNames = new ArrayList<>();
    for (String ppName : postProcessorNames) {
        if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
            BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class); // 后置处理器实例
            priorityOrderedPostProcessors.add(pp);
            if (pp instanceof MergedBeanDefinitionPostProcessor) {
                internalPostProcessors.add(pp);
            }
        }
        else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
            orderedPostProcessorNames.add(ppName);
        }
        else {
            nonOrderedPostProcessorNames.add(ppName);
        }
    }

    // First, register the BeanPostProcessors that implement PriorityOrdered.
    sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
    registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors); // 后置处理器实例注册到Bean工厂beanPostProcessors中

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

    // Now, register all regular BeanPostProcessors.
    List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
    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.
    sortPostProcessors(internalPostProcessors, beanFactory);
    registerBeanPostProcessors(beanFactory, internalPostProcessors);

    // Re-register post-processor for detecting inner beans as ApplicationListeners,
    // moving it to the end of the processor chain (for picking up proxies etc).
    beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}

上述涉及到Bean后置处理器注册，在BeanFactory中。