概述
invokeBeanFactoryPostProcessor方法是spring核心方法之一,主要用来调用beanFactory后置处理器来修改beanDefinition。
该方法实例化并调用已经注册到beanFactory的beanFactoryPostProcessor实例。
invokeBeanFactoryPostProcessors
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
// 获取到当前应用程序上下文的beanFactoryPostProcessors变量的值,并且实例化调用执行所有已经注册的beanFactoryPostProcessor
// 默认情况下,通过getBeanFactoryPostProcessors()来获取已经注册的BFPP,但是默认是空的
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());
// Detect a LoadTimeWeaver and prepare for weaving, if found in the meantime
// (e.g. through an @Bean method registered by ConfigurationClassPostProcessor)
if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
}
getBeanFactoryPostProcessors() 方法
方法获取自定义的BFPP方法,默认为空。
// TODO 如何设置自定义的BFPP?
invokeBeanFactoryPostProcessors方法
public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory,
List beanFactoryPostProcessors){}
参数:ConfigurableListableBeanFactory beanFactory是refresh()方法中的obtainFreshBeanFactory()方法获取的。
是DefaultListableBeanFactory 类型,DefaultListableBeanFactory类实现了BeanDefinitionRegistry接口。
public final ConfigurableListableBeanFactory getBeanFactory() {
DefaultListableBeanFactory beanFactory = this.beanFactory;
if (beanFactory == null) {
throw new IllegalStateException("BeanFactory not initialized or already closed - " +
"call 'refresh' before accessing beans via the ApplicationContext");
}
return beanFactory;
}
所以会走下面分支
if (beanFactory instanceof BeanDefinitionRegistry) {
...
}
否则直接调用外部beanFactoryPostProcessors的postProcessBeanFactory方法。
invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
BeanFactoryPostProcessor和BeanDefinitionRegistryPostProcessor分类
// 类型转换
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
// 此处希望大家做一个区分,两个接口是不同的,BeanDefinitionRegistryPostProcessor是BeanFactoryPostProcessor的子集
// BeanFactoryPostProcessor主要针对的操作对象是BeanFactory,而BeanDefinitionRegistryPostProcessor主要针对的操作对象是BeanDefinition
// 存放BeanFactoryPostProcessor的集合
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
// 存放BeanDefinitionRegistryPostProcessor的集合
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
// 首先处理入参中的beanFactoryPostProcessors,遍历所有的beanFactoryPostProcessors,将BeanDefinitionRegistryPostProcessor
// 和BeanFactoryPostProcessor区分开
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
// 如果是BeanDefinitionRegistryPostProcessor
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
// 直接执行BeanDefinitionRegistryPostProcessor接口中的postProcessBeanDefinitionRegistry方法
registryProcessor.postProcessBeanDefinitionRegistry(registry);
// 添加到registryProcessors,用于后续执行postProcessBeanFactory方法
registryProcessors.add(registryProcessor);
} else {
// 否则,只是普通的BeanFactoryPostProcessor,添加到regularPostProcessors,用于后续执行postProcessBeanFactory方法
regularPostProcessors.add(postProcessor);
}
}
处理实现了PriorityOrdered接口的BeanDefinitionRegistryPostProcessor类
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
// 调用所有实现PriorityOrdered接口的BeanDefinitionRegistryPostProcessor实现类
// 找到所有实现BeanDefinitionRegistryPostProcessor接口bean的beanName
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
// 遍历处理所有符合规则的postProcessorNames
for (String ppName : postProcessorNames) {
// 检测是否实现了PriorityOrdered接口
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
// 获取名字对应的bean实例,添加到currentRegistryProcessors中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
// 将要被执行的BFPP名称添加到processedBeans,避免后续重复执行
processedBeans.add(ppName);
}
}
// 按照优先级进行排序操作
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 添加到registryProcessors中,用于最后执行postProcessBeanFactory方法
registryProcessors.addAll(currentRegistryProcessors);
// 遍历currentRegistryProcessors,执行postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 执行完毕之后,清空currentRegistryProcessors
currentRegistryProcessors.clear();
处理实现了Ordered的BeanDefinitionRegistryPostProcessor类
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
// 检测是否实现了Ordered接口,并且还未执行过
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
// 获取名字对应的bean实例,添加到currentRegistryProcessors中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
// 将要被执行的BFPP名称添加到processedBeans,避免后续重复执行
processedBeans.add(ppName);
}
}
// 按照优先级进行排序操作
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 添加到registryProcessors中,用于最后执行postProcessBeanFactory方法
registryProcessors.addAll(currentRegistryProcessors);
// 遍历currentRegistryProcessors,执行postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 执行完毕之后,清空currentRegistryProcessors
currentRegistryProcessors.clear();
处理剩下的BeanDefinitionRegistryPostProcessor类
// 最后,调用所有剩下的BeanDefinitionRegistryPostProcessors
boolean reiterate = true;
while (reiterate) {
reiterate = false;
// 找出所有实现BeanDefinitionRegistryPostProcessor接口的类
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
// 遍历执行
for (String ppName : postProcessorNames) {
// 跳过已经执行过的BeanDefinitionRegistryPostProcessor
if (!processedBeans.contains(ppName)) {
// 获取名字对应的bean实例,添加到currentRegistryProcessors中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
// 将要被执行的BFPP名称添加到processedBeans,避免后续重复执行
processedBeans.add(ppName);
reiterate = true;
}
}
// 按照优先级进行排序操作
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 添加到registryProcessors中,用于最后执行postProcessBeanFactory方法
registryProcessors.addAll(currentRegistryProcessors);
// 遍历currentRegistryProcessors,执行postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 执行完毕之后,清空currentRegistryProcessors
currentRegistryProcessors.clear();
}
注意这里的reiterate变量在每找到一个未执行的BeanDefinitionRegistryPostProcessor实例都会被设置为true,表示invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);方法执行时可能会生成新的BeanDefinitionRegistryPostProcessor实例。
调用所有BeanDefinitionRegistryPostProcessor的postProcessBeanFactory方法
// 调用所有BeanDefinitionRegistryPostProcessor的postProcessBeanFactory方法
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
// 最后,调用入参beanFactoryPostProcessors中的普通BeanFactoryPostProcessor的postProcessBeanFactory方法
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
处理BeanFactory容器中注册的BeanFactoryPostProcessor类
处理方式与上面处理BeanDefinitionRegistryPostProcessor类似,按照先后顺序分别处理实现了PriorityOrdered接口、Ordered接口、没有实现Ordered接口的bean。这里不在详细说明。
// 到这里为止,入参beanFactoryPostProcessors和容器中的所有BeanDefinitionRegistryPostProcessor已经全部处理完毕,下面开始处理容器中
// 所有的BeanFactoryPostProcessor
// 可能会包含一些实现类,只实现了BeanFactoryPostProcessor,并没有实现BeanDefinitionRegistryPostProcessor接口,
// 因为有processedBeans记录了上面处理的实现了BeanDefinitionRegistryPostProcessor的类,所以不会重复处理。
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
regularPostProcessors = new ArrayList();
registryProcessors = new ArrayList();
currentRegistryProcessors = new ArrayList();
postProcessorNames = postProcessorNames;
int var20 = postProcessorNames.length;
String ppName;
for(var9 = 0; var9 < var20; ++var9) {
ppName = postProcessorNames[var9];
if (!processedBeans.contains(ppName)) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
regularPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
} else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
registryProcessors.add(ppName);
} else {
currentRegistryProcessors.add(ppName);
}
}
}
sortPostProcessors(regularPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors((Collection)regularPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList();
Iterator var21 = registryProcessors.iterator();
while(var21.hasNext()) {
String postProcessorName = (String)var21.next();
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors((Collection)orderedPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList();
Iterator var24 = currentRegistryProcessors.iterator();
while(var24.hasNext()) {
ppName = (String)var24.next();
nonOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
invokeBeanFactoryPostProcessors((Collection)nonOrderedPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
// 因为后置处理器可能已经修改了原始元数据,例如,替换值中的占位符
beanFactory.clearMetadataCache();
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