Spring之invokeBeanFactoryPostProcessors詳解
阿新 • • 發佈：2019-04-22
Spring的refresh的invokeBeanFactoryPostProcessors，就是呼叫所有註冊的、原始的BeanFactoryPostProcessor。
相關原始碼
public static void invokeBeanFactoryPostProcessors( ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) { // Invoke BeanDefinitionRegistryPostProcessors first, if any. Set<String> processedBeans = new HashSet<String>(); if (beanFactory instanceof BeanDefinitionRegistry) { ... 如果BeanFactory是BeanDefinitionRegistry型別，則特殊處理 ... } else { // Invoke factory processors registered with the context instance. // 呼叫使用者註冊的BeanFactoryPostProcessor invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory); } // 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. // 將BeanFactoryPostProcessor分開，分成PriorityOrdered、Ordered、其他型別 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 (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class)); } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessorNames.add(ppName); } else { nonOrderedPostProcessorNames.add(ppName); } } // First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered. // 首先呼叫實現PriorityOrdered型別的 OrderComparator.sort(priorityOrderedPostProcessors); invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory); // Next, invoke the BeanFactoryPostProcessors that implement Ordered. // 然後呼叫實現Ordered型別的 List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); for (String postProcessorName : orderedPostProcessorNames) { orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } OrderComparator.sort(orderedPostProcessors); invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory); // Finally, invoke all other BeanFactoryPostProcessors. // 最後呼叫其他型別的 List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>(); for (String postProcessorName : nonOrderedPostProcessorNames) { nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class)); } invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory); }
BeanFactory是BeanDefinitionRegistry型別，則特殊處理
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory; List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>(); List<BeanDefinitionRegistryPostProcessor> registryPostProcessors = new LinkedList<BeanDefinitionRegistryPostProcessor>(); // 區分一般的BeanFactoryPostProcessor和BeanDefinitionRegistryPostProcessor for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) { if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) { BeanDefinitionRegistryPostProcessor registryPostProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor; registryPostProcessor.postProcessBeanDefinitionRegistry(registry); registryPostProcessors.add(registryPostProcessor); } else { regularPostProcessors.add(postProcessor); } } // Do not initialize FactoryBeans here: We need to leave all regular beans // uninitialized to let the bean factory post-processors apply to them! // Separate between BeanDefinitionRegistryPostProcessors that implement // PriorityOrdered, Ordered, and the rest. String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); // First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered. List<BeanDefinitionRegistryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>(); for (String ppName : postProcessorNames) { if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); } } OrderComparator.sort(priorityOrderedPostProcessors); registryPostProcessors.addAll(priorityOrderedPostProcessors); invokeBeanDefinitionRegistryPostProcessors(priorityOrderedPostProcessors, registry); // Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered. postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); List<BeanDefinitionRegistryPostProcessor> orderedPostProcessors = new ArrayList<BeanDefinitionRegistryPostProcessor>(); for (String ppName : postProcessorNames) { if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) { orderedPostProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class)); processedBeans.add(ppName); } } OrderComparator.sort(orderedPostProcessors); registryPostProcessors.addAll(orderedPostProcessors); invokeBeanDefinitionRegistryPostProcessors(orderedPostProcessors, registry); // Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear. boolean reiterate = true; while (reiterate) { reiterate = false; postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); for (String ppName : postProcessorNames) { if (!processedBeans.contains(ppName)) { BeanDefinitionRegistryPostProcessor pp = beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class); registryPostProcessors.add(pp); processedBeans.add(ppName); pp.postProcessBeanDefinitionRegistry(registry); reiterate = true; } } } // Now, invoke the postProcessBeanFactory callback of all processors handled so far. invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory); invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
說明：
- 先處理使用者手動註冊的BeanFactoryPostProcessor，分為BeanDefinitionRegistryPostProcessor和BeanFactoryPostProcessor，並且BeanDefinitionRegistryPostProcessor會先呼叫其postXX方法
- 從容器獲取所有的BeanDefinitionRegistryPostProcessor型別，先處理實現PriorityOrdered型別的
- 再從容器獲取所有的BeanDefinitionRegistryPostProcessor型別，處理實現Ordered型別的
- 再從容器獲取所有的BeanDefinitionRegistryPostProcessor型別，處理剩下的，這裡有個遞迴，知道所有的BeanDefinitionRegistryPostProcessor都處理完
- BeanDefinitionRegistryPostProcessor也是BeanFactoryPostProcessor，最後處理BeanDefinitionRegistryPostProcessor從BeanFactoryPostProcessor繼承的方法
- 最後處理一般的BeanFactoryPostProcessor的postXXX方法
PS：BeanDefinitionRegistryPostProcessor有可能會動態新增新的BeanDefinitionRegistryPostProcessor，所有這裡每次都從容器中重新獲得所有的BeanDefinitionRegistryPostProcessor。 PS：BeanDefinitionRegistryPostProcessor的回撥方法，先於BeanFactoryPostProcessor的回撥方法執行。
/**
* Invoke the given BeanDefinitionRegistryPostProcessor beans.
*/
private static void invokeBeanDefinitionRegistryPostProcessors(
Collection<? extends BeanDefinitionRegistryPostProcessor> postProcessors, BeanDefinitionRegistry registry) {
for (BeanDefinitionRegistryPostProcessor postProcessor : postProcessors) {
postProcessor.postProcessBeanDefinitionRegistry(registry);
}
}
/**
* Invoke the given BeanFactoryPostProcessor beans.
*/
private static void invokeBeanFactoryPostProcessors(
Collection<? extends BeanFactoryPostProcessor> postProcessors, ConfigurableListableBeanFactory beanFactory) {
for (BeanFactoryPostProcessor postProcessor : postProcessors) {
postProcessor.postProcessBeanFactory(beanFactory);
}
}