spring源码学习笔记-初始化（二） PostProcessor

下面我们重点查看这个方法：

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory)

这个方法主要是实例化和反调所有注册的BeanFactoryProcessor  对象集，必须调用在单个实例之前。

// Invoke BeanDefinitionRegistryPostProcessors first, if any.Set<String> processedBeans = new HashSet<String>();if (beanFactory instanceof BeanDefinitionRegistry) {BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>();List<BeanDefinitionRegistryPostProcessor> registryPostProcessors =new LinkedList<BeanDefinitionRegistryPostProcessor>();for (BeanFactoryPostProcessor postProcessor : getBeanFactoryPostProcessors()) {if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {BeanDefinitionRegistryPostProcessor registryPostProcessor =(BeanDefinitionRegistryPostProcessor) postProcessor;registryPostProcessor.postProcessBeanDefinitionRegistry(registry);registryPostProcessors.add(registryPostProcessor);}else {regularPostProcessors.add(postProcessor);}}Map<String, BeanDefinitionRegistryPostProcessor> beanMap =beanFactory.getBeansOfType(BeanDefinitionRegistryPostProcessor.class, true, false);List<BeanDefinitionRegistryPostProcessor> registryPostProcessorBeans =new ArrayList<BeanDefinitionRegistryPostProcessor>(beanMap.values());OrderComparator.sort(registryPostProcessorBeans);for (BeanDefinitionRegistryPostProcessor postProcessor : registryPostProcessorBeans) {postProcessor.postProcessBeanDefinitionRegistry(registry);}invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(registryPostProcessorBeans, beanFactory);invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);processedBeans.addAll(beanMap.keySet());}else {// Invoke factory processors registered with the context instance.invokeBeanFactoryPostProcessors(getBeanFactoryPostProcessors(), beanFactory);}

上面代码第2句是创建一个Set集合，第3句是判断传入的beanFactory是否实现BeanDefinitionRegistry的接口，实现了，进入if方法。

上塑造型，把beanFactory上溯到BeanDefinitionRegistry接口，第5行代码创建一个LinkedList集合，里面存放BeanFactoryPostProcessor对象。第6行代码

创建一个LinkList集合，registryPostProcessors用来存放一些用来对bean定义的注册信息进行处理的PostProcessor。

第8行循环对普通的PostProcessor进行循环；第9行代码判断postProcessor是否为对bean定义的注册信息进行处理的PostProcessor，

如果是的话，对其进行相应的业务处理，否则处理普通的postProcessor.

代码二：

Map<String, BeanDefinitionRegistryPostProcessor> beanMap =beanFactory.getBeansOfType(BeanDefinitionRegistryPostProcessor.class, true, false);List<BeanDefinitionRegistryPostProcessor> registryPostProcessorBeans =new ArrayList<BeanDefinitionRegistryPostProcessor>(beanMap.values());OrderComparator.sort(registryPostProcessorBeans);for (BeanDefinitionRegistryPostProcessor postProcessor : registryPostProcessorBeans) {postProcessor.postProcessBeanDefinitionRegistry(registry);}invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(registryPostProcessorBeans, beanFactory);invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);processedBeans.addAll(beanMap.keySet());

第1行是对bean定义注册信息进行处理的PostProcessor的beanType的获取，第3行通过beanMaps得到registryPostProcessorBeans；

第5行调用排序方法对registryPostProcessorBeans进行排序，第6-8行调用registryPostProcessorBeans，

第9-12行，调用invokeBeanFactoryPostPrcessors方法，就是为每个PostProcessor，进行postProcessor.postProcessBeanFactory()方法调用。

13行，processedBeans存放所有BeanDefinitionRegistryPostProcessor类型的对象。

代码三：

// Do not initialize FactoryBeans here: We need to leave all regular beans// uninitialized to let the bean factory post-processors apply to them!String[] postProcessorNames =beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,// Ordered, and the rest.List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();List<String> orderedPostProcessorNames = new ArrayList<String>();List<String> nonOrderedPostProcessorNames = new ArrayList<String>();for (String ppName : postProcessorNames) {if (processedBeans.contains(ppName)) {// skip - already processed in first phase above}else if (isTypeMatch(ppName, PriorityOrdered.class)) {priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));}else if (isTypeMatch(ppName, Ordered.class)) {orderedPostProcessorNames.add(ppName);}else {nonOrderedPostProcessorNames.add(ppName);}}// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.OrderComparator.sort(priorityOrderedPostProcessors);invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);// Next, invoke the BeanFactoryPostProcessors that implement Ordered.List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();for (String postProcessorName : orderedPostProcessorNames) {orderedPostProcessors.add(getBean(postProcessorName, BeanFactoryPostProcessor.class));}OrderComparator.sort(orderedPostProcessors);invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);// Finally, invoke all other BeanFactoryPostProcessors.List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();for (String postProcessorName : nonOrderedPostProcessorNames) {nonOrderedPostProcessors.add(getBean(postProcessorName, BeanFactoryPostProcessor.class));}invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);