第五章 spring-connet之AnnotationConfigUtils

前言

AnnotatedBeanDefinitionReader是AnnctionConfig相關上下文與AnnotationConfigUtils的橋樑。還有一個做用是解析class成爲BeanDefinitionHolder，註冊到容器裏面。AnnotationConfigUtils是AnnctionConfig相關上下文最核心點，若是弄清楚AnnctionConfig相關上下文，那麼就知道註解讀取相關的機制。

registerAnnotationConfigProcessors方法

registerAnnotationConfigProcessors方法負責向容器裏面註冊相關的類。基本都給予某個體系。靜態方法registerAnnotationConfigProcessors向容器裏面註冊了不少東西了。

1. AnnotationAwareOrderComparator註解排序類。對Order註解進行排序
2. ContextAnnotationAutowireCandidateResolver 處理Qualifier註解，這個點可能須要深刻解讀，spring設計得太複雜了。
3. ConfigurationClassPostProcessor 獲得componentScan註解計算基本目錄，並掃描對應目錄。處理的註解還有PropertySources，Imports，Bean等等
4. AutowiredAnnotationBeanPostProcessor 基於spring bean的監視週期（BeanPostProcessor），掃描Autowired註解
5. RequiredAnnotationBeanPostProcessor 基於spring bean的監視週期（BeanPostProcessor），掃描Required註解，這個沒啥用把
6. CommonAnnotationBeanPostProcessor 對javax.xml.ws.WebServiceRef註解與javax.ejb.EJB註解的兼容，真噁心
7. PersistenceAnnotationBeanPostProcessor 對jpa註解的兼容
8. EventListenerMethodProcessor 當全部bean（除了lazy）完成實例化以後，調用。找bean的方法室友有EventListener註解
9. DefaultEventListenerFactory 對EventListenerMethodProcessor的支持，目前不知曉有什麼用

public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(
			BeanDefinitionRegistry registry, Objespringct source) {

		DefaultListableBeanFactory beanFactory = unwrapDefaultListableBeanFactory(registry);
		if (beanFactory != null) {
			if (!(beanFactory.getDependencyComparator() instanceof AnnotationAwareOrderComparator)) {
				beanFactory.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
			}
			if (!(beanFactory.getAutowireCandidateResolver() instanceof ContextAnnotationAutowireCandidateResolver)) {
				beanFactory.setAutowireCandidateResolver(new ContextAnnotationAutowireCandidateResolver());
			}
		}

		Set<BeanDefinitionHolder> beanDefs = new LinkedHashSet<BeanDefinitionHolder>(4);

		if (!registry.containsBeanDefinition(CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME)) {
			RootBeanDefinition def = new RootBeanDefinition(ConfigurationClassPostProcessor.class);
			def.setSource(source);
			beanDefs.add(registerPostProcessor(registry, def, CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME));
		}

		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));
		}

		if (!registry.containsBeanDefinition(REQUIRED_ANNOTATION_PROCESSOR_BEAN_NAME)) {
			RootBeanDefinition def = new RootBeanDefinition(RequiredAnnotationBeanPostProcessor.class);
			def.setSource(source);
			beanDefs.add(registerPostProcessor(registry, def, REQUIRED_ANNOTATION_PROCESSOR_BEAN_NAME));
		}

		// Check for JSR-250 support, and if present add the CommonAnnotationBeanPostProcessor.
		if (jsr250Present && !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));
		}

		// Check for JPA support, and if present add the 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));
		}

		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));
		}
		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;
	}

總結

registerAnnotationConfigProcessors方法基本把主動性註解註冊到容器裏面了。若是在把掃面體系搞定，大部分註解都ok了，除了spring-boot的註解體系

processCommonDefinitionAnnotations方法

spring的annatated內容讀取有三種方式反射，字節碼，還有直接取。processCommonDefinitionAnnotations方法就是直接取spring明肯定義的一些註解。這些註解都比較少時間，你們看下就好了。

static void processCommonDefinitionAnnotations(AnnotatedBeanDefinition abd, AnnotatedTypeMetadata metadata) {
		if (metadata.isAnnotated(Lazy.class.getName())) {
			abd.setLazyInit(attributesFor(metadata, Lazy.class).getBoolean("value"));
		}
		else if (abd.getMetadata() != metadata && abd.getMetadata().isAnnotated(Lazy.class.getName())) {
			abd.setLazyInit(attributesFor(abd.getMetadata(), Lazy.class).getBoolean("value"));
		}

		if (metadata.isAnnotated(Primary.class.getName())) {
			abd.setPrimary(true);
		}
		if (metadata.isAnnotated(DependsOn.class.getName())) {
			abd.setDependsOn(attributesFor(metadata, DependsOn.class).getStringArray("value"));
		}

		if (abd instanceof AbstractBeanDefinition) {
			AbstractBeanDefinition absBd = (AbstractBeanDefinition) abd;
			if (metadata.isAnnotated(Role.class.getName())) {
				absBd.setRole(attributesFor(metadata, Role.class).getNumber("value").intValue());
			}
			if (metadata.isAnnotated(Description.class.getName())) {
				absBd.setDescription(attributesFor(metadata, Description.class).getString("value"));
			}
		}
	}

隨便說說

原本應該在9月19日完成，19日凌晨失眠，而後取了八卦嶺吃東西。..............