本文主要讲述Spring是如何解析“annotation-config”,实际是加载注解对应解析器。
解析内容
1、解析的元素是:
<context:annotation-config/>
2、加载注解对应的解析器。
加载解析器
AnnotationConfigBeanDefinitionParser.parse(Element element, ParserContext parserContext)
此处element即为“context:annotation-config”。
public BeanDefinition parse(Element element, ParserContext parserContext) {
Object source = parserContext.extractSource(element);
// 获取所有处理注解类的BeanPostProcessors(BeanPostProcessor本身也是bean) 注1
Set<BeanDefinitionHolder> processorDefinitions =
AnnotationConfigUtils.registerAnnotationConfigProcessors(parserContext.getRegistry(), source);
// 生成关于元素(context:annotation-config)的组合组件(Component即bean),放到到解析容器待处理队列containingComponents中
CompositeComponentDefinition compDefinition = new CompositeComponentDefinition(element.getTagName(), source);
parserContext.pushContainingComponent(compDefinition);
// 把注解BeanPostProcessor的BeanDefinition转换成ComponentDefinition,注册到解析容器的containingComponents的嵌套组件中
for (BeanDefinitionHolder processorDefinition : processorDefinitions) {
parserContext.registerComponent(new BeanComponentDefinition(processorDefinition));
}
// 触发组件注册事件
parserContext.popAndRegisterContainingComponent();
return null;
}
注1:注解类的BeanPostProcessors都是SF框架提供。文章来源:https://www.toymoban.com/news/detail-579218.html
AnnotationConfigUtils.registerAnnotationConfigProcessors( BeanDefinitionRegistry registry, @Nullable Object source)
1、设置bean工厂用于注解处理的属性实例(包括:AnnotationAwareOrderComparator、ContextAnnotationAutowireCandidateResolver、ContextAnnotationAutowireCandidateResolver)
2、把Spring用于解析注解的处理器bean(包括:ConfigurationClassPostProcessor、AutowiredAnnotationBeanPostProcessor、CommonAnnotationBeanPostProcessor、InitDestroyAnnotationBeanPostProcessor、PersistenceAnnotationBeanPostProcessor、EventListenerMethodProcessor、DefaultEventListenerFactory)的BeanDefinition形成集合返回文章来源地址https://www.toymoban.com/news/detail-579218.html
public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(
BeanDefinitionRegistry registry, Object source) {
DefaultListableBeanFactory beanFactory = unwrapDefaultListableBeanFactory(registry);
if (beanFactory != null) {
if (!(beanFactory.getDependencyComparator() instanceof AnnotationAwareOrderComparator)) {
// 设置dependencyComparator属性
beanFactory.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
}
if (!(beanFactory.getAutowireCandidateResolver() instanceof ContextAnnotationAutowireCandidateResolver)) {
// 设置autowireCandidateResolver属性(设置自动注入候选对象的解析器,用于判断BeanDefinition是否为候选对象)
beanFactory.setAutowireCandidateResolver(new ContextAnnotationAutowireCandidateResolver());
}
}
Set<BeanDefinitionHolder> beanDefs = new LinkedHashSet<BeanDefinitionHolder>(4);
// 注册内部管理的用于处理@Configuration注解的后置处理器bean-ConfigurationClassPostProcessor
if (!registry.containsBeanDefinition(CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(ConfigurationClassPostProcessor.class);
def.setSource(source);
// registerPostProcessor: 注册BeanDefinition到注册表中
beanDefs.add(registerPostProcessor(registry, def, CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME));
}
// 注册内部管理的用于处理@Autowired、@Value、@Inject以及@Lookup注解的后置处理器bean-AutowiredAnnotationBeanPostProcessor
if (!registry.containsBeanDefinition(AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(AutowiredAnnotationBeanPostProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME));
}
// 支持Jakarta注解,注册内部管理注解通用后置处理器bean-CommonAnnotationBeanPostProcessor
if (jakartaAnnotationsPresent && !registry.containsBeanDefinition(COMMON_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(CommonAnnotationBeanPostProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, COMMON_ANNOTATION_PROCESSOR_BEAN_NAME));
}
// 支持JSR-250注解(@PostConstruct,@PreDestroy)后置处理器的bean-InitDestroyAnnotationBeanPostProcessor
if (jsr250Present && !registry.containsBeanDefinition(JSR250_ANNOTATION_PROCESSOR_BEAN_NAME)) {
try {
RootBeanDefinition def = new RootBeanDefinition(InitDestroyAnnotationBeanPostProcessor.class);
def.getPropertyValues().add("initAnnotationType", classLoader.loadClass("javax.annotation.PostConstruct"));
def.getPropertyValues().add("destroyAnnotationType", classLoader.loadClass("javax.annotation.PreDestroy"));
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, JSR250_ANNOTATION_PROCESSOR_BEAN_NAME));
}
catch (ClassNotFoundException ex) {
// Failed to load javax variants of the annotation types -> ignore.
}
}
// 注册内部管理的用于处理JPA注解的后置处理器bean-PersistenceAnnotationBeanPostProcessor
if (jpaPresent && !registry.containsBeanDefinition(PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition();
try {
def.setBeanClass(ClassUtils.forName(PERSISTENCE_ANNOTATION_PROCESSOR_CLASS_NAME,
AnnotationConfigUtils.class.getClassLoader()));
} catch (ClassNotFoundException ex) {
throw new IllegalStateException(
"Cannot load optional framework class: " + PERSISTENCE_ANNOTATION_PROCESSOR_CLASS_NAME, ex);
}
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME));
}
// 注册内部管理的用于处理@EventListener注解的后置处理器bean
if (!registry.containsBeanDefinition(EVENT_LISTENER_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(EventListenerMethodProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, EVENT_LISTENER_PROCESSOR_BEAN_NAME));
}
// 注册内部管理用于生产ApplicationListener对象的EventListenerFactory对象
if (!registry.containsBeanDefinition(EVENT_LISTENER_FACTORY_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(DefaultEventListenerFactory.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, EVENT_LISTENER_FACTORY_BEAN_NAME));
}
return beanDefs;
}
private static BeanDefinitionHolder registerPostProcessor(
BeanDefinitionRegistry registry, RootBeanDefinition definition, String beanName) {
// 设置role
definition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
// 注册BeanDefinition
registry.registerBeanDefinition(beanName, definition);
// 封装成BeanDefinitionHolder并返回
return new BeanDefinitionHolder(definition, beanName);
}
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