01.Spring Framework 源码解析之启动容器

1. 环境搭建

代码已经上传至 https://github.com/masteryourself/spring-framework，工程是 tutorial-spring-start

2. 源码解析

详细的源码注释可参考 https://github.com/masteryourself/spring-framework

2.1 初始化流程

2.1.1 流程分析

2.1.2 核心代码剖析

1. org.springframework.context.annotation.AnnotationConfigUtils#registerAnnotationConfigProcessors

public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(
		BeanDefinitionRegistry registry, @Nullable Object 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<>(8);
	// 向 beanDefinitionMap 中注册【BeanFactoryPostProcessor】：【ConfigurationClassPostProcessor】
	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));
	}
	// 向 beanDefinitionMap 中注册【BeanPostProcessor】：【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));
	}

	// Check for JSR-250 support, and if present add the CommonAnnotationBeanPostProcessor.
	// 向 beanDefinitionMap 中注册【BeanPostProcessor】：【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.
	// 向 beanDefinitionMap 中注册【BeanPostProcessor】：【PersistenceAnnotationBeanPostProcessor】，前提条件是在 jpa 环境下
	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));
	}
	// 向 beanDefinitionMap 中注册【BeanFactoryPostProcessor】：【EventListenerMethodProcessor】
	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));
	}
	// 向 beanDefinitionMap 中注册组件：【DefaultEventListenerFactory】
	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;
}

2. org.springframework.context.annotation.AnnotatedBeanDefinitionReader#doRegisterBean

<T> void doRegisterBean(Class<T> annotatedClass, @Nullable Supplier<T> instanceSupplier, @Nullable String name,
		@Nullable Class<? extends Annotation>[] qualifiers, BeanDefinitionCustomizer... definitionCustomizers) {
   
   
	// 解析传入的配置类，实际上这个方法既可以解析配置类，也可以解析 Spring bean 对象
	AnnotatedGenericBeanDefinition abd = new AnnotatedGenericBeanDefinition(annotatedClass);
	// 判断是否需要跳过，判断依据是此类上有没有 @Conditional 注解
	if (this.conditionEvaluator.shouldSkip(abd.getMetadata())) {
   
   
		return;
	}

	abd.setInstanceSupplier(instanceSupplier);
	ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(abd);
	abd.setScope(scopeMetadata.getScopeName());
	String beanName = (name != null ? name : this.beanNameGenerator.generateBeanName(abd, this.registry));
	// 处理类上的通用注解
	AnnotationConfigUtils.processCommonDefinitionAnnotations(abd);
	if (qualifiers != null) {
   
   
		for (Class<? extends Annotation> qualifier : qualifiers) {
   
   
			if (Primary.class == qualifier) {
   
   
				abd.setPrimary(true);
			}
			else if (Lazy.class == qualifier) {
   
   
				abd.setLazyInit(true);
			}
			else {
   
   
				abd.addQualifier(new AutowireCandidateQualifier(qualifier));