Spring注入源码分析（二）

五、invokeBeanFactoryPostProcessors源码分析

之前已经通过xml和注解将java以map的形式进行注入，接下来，我们来看一下java配置注入是怎么完成的

	invokeBeanFactoryPostProcessors(beanFactory);

	protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
		//核心方法
		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()));
		}
	}
	
	public static void invokeBeanFactoryPostProcessors(
			ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {

		// Invoke BeanDefinitionRegistryPostProcessors first, if any.
		Set<String> processedBeans = new HashSet<>();

		if (beanFactory instanceof BeanDefinitionRegistry) {
			BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
			List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
			List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();

			for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
				if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
					BeanDefinitionRegistryPostProcessor registryProcessor =
							(BeanDefinitionRegistryPostProcessor) postProcessor;
					registryProcessor.postProcessBeanDefinitionRegistry(registry);
					registryProcessors.add(registryProcessor);
				}
				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.
			List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();

			// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
			String[] postProcessorNames =
					beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
			for (String ppName : postProcessorNames) {
				if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
					currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
					processedBeans.add(ppName);
				}
			}
			sortPostProcessors(currentRegistryProcessors, beanFactory);
			registryProcessors.addAll(currentRegistryProcessors);
			//核心方法，使用之前默认注入的Processors完成java配置注入
			invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
			currentRegistryProcessors.clear();

			// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
			postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
			for (String ppName : postProcessorNames) {
				if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
					currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
					processedBeans.add(ppName);
				}
			}
			sortPostProcessors(currentRegistryProcessors, beanFactory);
			registryProcessors.addAll(currentRegistryProcessors);
			invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
			currentRegistryProcessors.clear();

			// 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)) {
						currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
						processedBeans.add(ppName);
						reiterate = true;
					}
				}
				sortPostProcessors(currentRegistryProcessors, beanFactory);
				registryProcessors.addAll(currentRegistryProcessors);
				invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
				currentRegistryProcessors.clear();
			}

			// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
			invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
			invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
		}

		else {
			// Invoke factory processors registered with the context instance.
			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.
		List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
		List<String> orderedPostProcessorNames = new ArrayList<>();
		List<String> nonOrderedPostProcessorNames = new ArrayList<>();
		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.
		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);

		// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
		List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();
		for (String postProcessorName : orderedPostProcessorNames) {
			orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
		}
		sortPostProcessors(orderedPostProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);

		// Finally, invoke all other BeanFactoryPostProcessors.
		List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
		for (String postProcessorName : nonOrderedPostProcessorNames) {
			nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
		}
		invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);

		// Clear cached merged bean definitions since the post-processors might have
		// modified the original metadata, e.g. replacing placeholders in values...
		beanFactory.clearMetadataCache();
	}

	//经过一系列的循环，将所有Process取出来对bean进行执行，现阶段只有一个Process
	@Override
	public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
		int registryId = System.identityHashCode(registry);
		if (this.registriesPostProcessed.contains(registryId)) {
			throw new IllegalStateException(
					"postProcessBeanDefinitionRegistry already called on this post-processor against " + registry);
		}
		if (this.factoriesPostProcessed.contains(registryId)) {
			throw new IllegalStateException(
					"postProcessBeanFactory already called on this post-processor against " + registry);
		}
		this.registriesPostProcessed.add(registryId);
		
		//核心方法，此时的registry就是beanFactory
		processConfigBeanDefinitions(registry);
	}

进入核心方法，完成java配置方式注入

	public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
		List<BeanDefinitionHolder> configCandidates = new ArrayList<>();
		String[] candidateNames = registry.getBeanDefinitionNames();
		//将所有的bean进行循环
		for (String beanName : candidateNames) {
			BeanDefinition beanDef = registry.getBeanDefinition(beanName);
			if (ConfigurationClassUtils.isFullConfigurationClass(beanDef) ||
					ConfigurationClassUtils.isLiteConfigurationClass(beanDef)) {
				if (logger.isDebugEnabled()) {
					logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
				}
			}
			else if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
				//将有@Configuration配置的bean找出来，放在一个list
				configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
			}
		}

		// list为空，说明没有@Configuration配置的bean就直接退出，没有java配置
		if (configCandidates.isEmpty()) {
			return;
		}

		// 排序
		configCandidates.sort((bd1, bd2) -> {
			int i1 = ConfigurationClassUtils.getOrder(bd1.getBeanDefinition());
			int i2 = ConfigurationClassUtils.getOrder(bd2.getBeanDefinition());
			return Integer.compare(i1, i2);
		});

		// Detect any custom bean name generation strategy supplied through the enclosing application context
		SingletonBeanRegistry sbr = null;
		if (registry instanceof SingletonBeanRegistry) {
			sbr = (SingletonBeanRegistry) registry;
			if (!this.localBeanNameGeneratorSet) {
				BeanNameGenerator generator = (BeanNameGenerator) sbr.getSingleton(CONFIGURATION_BEAN_NAME_GENERATOR);
				if (generator != null) {
					this.componentScanBeanNameGenerator = generator;
					this.importBeanNameGenerator = generator;
				}
			}
		}

		if (this.environment == null) {
			this.environment = new StandardEnvironment();
		}

		//创建ConfigurationClassParser ，用来解析java配置
		//将注解工厂，registry作为他的属性，registry就是beanFactory
		ConfigurationClassParser parser = new ConfigurationClassParser(
				this.metadataReaderFactory, this.problemReporter, this.environment,
				this.resourceLoader, this.componentScanBeanNameGenerator, registry);
		//将之前有@Configuration注解的类放在一个set
		Set<BeanDefinitionHolder> candidates = new LinkedHashSet<>(configCandidates);
		Set<ConfigurationClass> alreadyParsed = new HashSet<>(configCandidates.size());
		do {
			//解析，核心方法(至少会执行一次)，这个parser就是ConfigurationClassParser，属性中有beanFactor，有注解相关信息，环境信息
			parser.parse(candidates);
			//校验
			parser.validate();
	
			Set<ConfigurationClass> configClasses = new LinkedHashSet<>(parser.getConfigurationClasses());
			configClasses.removeAll(alreadyParsed);

			// Read the model and create bean definitions based on its content
			if (this.reader == null) {
				this.reader = new ConfigurationClassBeanDefinitionReader(
						registry, this.sourceExtractor, this.resourceLoader, this.environment,
						this.importBeanNameGenerator, parser.getImportRegistry());
			}
			this.reader.loadBeanDefinitions(configClasses);
			alreadyParsed.addAll(configClasses);
			//将candidates清空，配置while循环退出，在这里之前会一次性全部解析
			candidates.clear();
			if (registry.getBeanDefinitionCount() > candidateNames.length) {
				String[] newCandidateNames = registry.getBeanDefinitionNames();
				Set<String> oldCandidateNames = new HashSet<>(Arrays.asList(candidateNames));
				Set<String> alreadyParsedClasses = new HashSet<>();
				for (ConfigurationClass configurationClass : alreadyParsed) {
					alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
				}
				for (String candidateName : newCandidateNames) {
					if (!oldCandidateNames.contains(candidateName)) {
						BeanDefinition bd = registry.getBeanDefinition(candidateName);
						if (ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) &&
								!alreadyParsedClasses.contains(bd.getBeanClassName())) {
							candidates.add(new BeanDefinitionHolder(bd, candidateName));
						}
					}
				}
				candidateNames = newCandidateNames;
			}
		}
		while (!candidates.isEmpty());

		// Register the ImportRegistry as a bean in order to support ImportAware @Configuration classes
		if (sbr != null && !sbr.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
			sbr.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
		}

		if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
			// Clear cache in externally provided MetadataReaderFactory; this is a no-op
			// for a shared cache since it'll be cleared by the ApplicationContext.
			((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
		}
	}

下面我们就来看一个这个ConfigurationClassParser 解析器的核心方法parse()

	public void parse(Set<BeanDefinitionHolder> configCandidates) {
		for (BeanDefinitionHolder holder : configCandidates) {
			BeanDefinition bd = holder.getBeanDefinition();
			try {
				//类型判断，是不是注解，我们这就是注解
				if (bd instanceof AnnotatedBeanDefinition) {
					parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName());
				}
				else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition) bd).hasBeanClass()) {
					parse(((AbstractBeanDefinition) bd).getBeanClass(), holder.getBeanName());
				}
				else {
					parse(bd.getBeanClassName(), holder.getBeanName());
				}
			}
			catch (BeanDefinitionStoreException ex) {
				throw ex;
			}
			catch (Throwable ex) {
				throw new BeanDefinitionStoreException(
						"Failed to parse configuration class [" + bd.getBeanClassName() + "]", ex);
			}
		}

		this.deferredImportSelectorHandler.process();
	}
	
	//将注解信息，beanBean传进来封装一个对象
	protected final void parse(AnnotationMetadata metadata, String beanName) throws IOException {
		processConfigurationClass(new ConfigurationClass(metadata, beanName));
	}

	protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
		if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) {
			return;
		}

		ConfigurationClass existingClass = this.configurationClasses.get(configClass);
		if (existingClass != null) {
			if (configClass.isImported()) {
				if (existingClass.isImported()) {
					existingClass.mergeImportedBy(configClass);
				}
				// Otherwise ignore new imported config class; existing non-imported class overrides it.
				return;
			}
			else {
				// Explicit bean definition found, probably replacing an import.
				// Let's remove the old one and go with the new one.
				this.configurationClasses.remove(configClass);
				this.knownSuperclasses.values().removeIf(configClass::equals);
			}
		}

		// Recursively process the configuration class and its superclass hierarchy.
		SourceClass sourceClass = asSourceClass(configClass);
		do {
			//核心方法，解析，解析完成后，就在sourceClass 的beanMethods属性中调价@Bean方法信息
			sourceClass = doProcessConfigurationClass(configClass, sourceClass);
		}
		while (sourceClass != null);
		//最后configurationClasses将存入配置类信息sourceClass 
		this.configurationClasses.put(configClass, configClass);
	}
	
	//这个方法很重要！！！！！
	protected final SourceClass doProcessConfigurationClass(ConfigurationClass configClass, SourceClass sourceClass)
			throws IOException {
		//有没有@Component注解，@Configuration里面有@Component
		if (configClass.getMetadata().isAnnotated(Component.class.getName())) {
			// Recursively process any member (nested) classes first
			processMemberClasses(configClass, sourceClass);
		}

		// 处理 @PropertySource 
		for (AnnotationAttributes propertySource : AnnotationConfigUtils.attributesForRepeatable(
				sourceClass.getMetadata(), PropertySources.class,
				org.springframework.context.annotation.PropertySource.class)) {
			if (this.environment instanceof ConfigurableEnvironment) {
				processPropertySource(propertySource);
			}
			else {
				logger.info("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() +
						"]. Reason: Environment must implement ConfigurableEnvironment");
			}
		}

		//处理 @componentScans ，如果发现有@componentScans，就会和xml中的包扫面走相同的路线
		Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(
				sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class);
		if (!componentScans.isEmpty() &&
				!this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
			for (AnnotationAttributes componentScan : componentScans) {
				//循环出每一个componentScan，并将扫描结果解析为scannedBeanDefinitions，
				//这和时候已经调用了doScan方法，将扫面出来的bean全部写入map中 
				//扫描的对象已经全部写在map，如果扫描对象中有@Configuration，又回到了上一章的问题，上一张在doScan中扫面出来的@Configuration bean准备在这一章处理，下面我就来看一下具体怎么处理
				Set<BeanDefinitionHolder> scannedBeanDefinitions =
						this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName());
				// 对扫描出的scannedBeanDefinitions进行一个一个处理
				for (BeanDefinitionHolder holder : scannedBeanDefinitions) {
					BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition();
					if (bdCand == null) {
						bdCand = holder.getBeanDefinition();
					}
					if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) {
						//解析，这个方法之前出现过，就是最开始的入口，一个递归
						//又会调用前面的方法，判断是普通的注入对象还是配置对象
						//如果有配置对象，在进行分析配置对象的注解，
						//如果有Scan,import,Bean，直到没有配置对象为止，这个方法就走完了
						//最终的流程就是，得到配置类，检查配置的配置信息，只有@bean，就讲@Bean注入就可以了，有Scan，就先扫描，再走相同的流程，直到这个Scan完成，有import也会保证xml解析完
						//总的来说这就是一个大的递归，一层一层的解析，一个配置类一个配置类的解析，扫面后者import过程中遇到了配置对象，就先解析这个配置对象
						parse(bdCand.getBeanClassName(), holder.getBeanName());
					}
				}
			}
		}

		//处理 @Import ，有xml导入，就会走xml解析的路线
		processImports(configClass, sourceClass, getImports(sourceClass), true);


		AnnotationAttributes importResource =
				AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class);
		if (importResource != null) {
			String[] resources = importResource.getStringArray("locations");
			Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader");
			for (String resource : resources) {
				String resolvedResource = this.environment.resolveRequiredPlaceholders(resource);
				configClass.addImportedResource(resolvedResource, readerClass);
			}
		}

		// 处理 @Bean methods===》 java配置，最后处理java配置
		//得到所有的方法注解
		Set<MethodMetadata> beanMethods = retrieveBeanMethodMetadata(sourceClass);
		for (MethodMetadata methodMetadata : beanMethods) {
			//将注解方法信息添加到BeanMethod
			configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass));
		}

		processInterfaces(configClass, sourceClass);

		// Process superclass, if any
		if (sourceClass.getMetadata().hasSuperClass()) {
			String superclass = sourceClass.getMetadata().getSuperClassName();
			if (superclass != null && !superclass.startsWith("java") &&
					!this.knownSuperclasses.containsKey(superclass)) {
				this.knownSuperclasses.put(superclass, configClass);
				// Superclass found, return its annotation metadata and recurse
				return sourceClass.getSuperClass();
			}
		}

		// No superclass -> processing is complete
		return null;
	}

这里执行完成后，我们就讲所有的@bean的方法去了出来，回到之前的代码

do {
			//解析配置@Configuration文件，这里只会解析xml在中的文件
			//在后面扫描到的@Configuration都放在了configClasses里面
			//这类的配置文件会产生多个配置文件(Sacn或者imoprt)，每一个都会增加configClasses 的长度
			//每个配置文件的method都会存在单个configClasse的method里面，因此可以取出所有有这个配置文件产生的method
			parser.parse(candidates);
			parser.validate();

			Set<ConfigurationClass> configClasses = new LinkedHashSet<>(parser.getConfigurationClasses());
			configClasses.removeAll(alreadyParsed);

			// Read the model and create bean definitions based on its content
			if (this.reader == null) {
				this.reader = new ConfigurationClassBeanDefinitionReader(
						registry, this.sourceExtractor, this.resourceLoader, this.environment,
						this.importBeanNameGenerator, parser.getImportRegistry());
			}
			//将java配置的bean转化为map
			this.reader.loadBeanDefinitions(configClasses);
			alreadyParsed.addAll(configClasses);

			candidates.clear();
			if (registry.getBeanDefinitionCount() > candidateNames.length) {
				String[] newCandidateNames = registry.getBeanDefinitionNames();
				Set<String> oldCandidateNames = new HashSet<>(Arrays.asList(candidateNames));
				Set<String> alreadyParsedClasses = new HashSet<>();
				for (ConfigurationClass configurationClass : alreadyParsed) {
					alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
				}
				for (String candidateName : newCandidateNames) {
					if (!oldCandidateNames.contains(candidateName)) {
						BeanDefinition bd = registry.getBeanDefinition(candidateName);
						if (ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) &&
								!alreadyParsedClasses.contains(bd.getBeanClassName())) {
							candidates.add(new BeanDefinitionHolder(bd, candidateName));
						}
					}
				}
				candidateNames = newCandidateNames;
			}
		}
		while (!candidates.isEmpty());


	//循环转化
	public void loadBeanDefinitions(Set<ConfigurationClass> configurationModel) {
		//条件执行器，到底这个bean要不要注入
		TrackedConditionEvaluator trackedConditionEvaluator = new TrackedConditionEvaluator();
		for (ConfigurationClass configClass : configurationModel) {
			//将单个configClass取出来
			loadBeanDefinitionsForConfigurationClass(configClass, trackedConditionEvaluator);
		}
	}


	private void loadBeanDefinitionsForConfigurationClass(
			ConfigurationClass configClass, TrackedConditionEvaluator trackedConditionEvaluator) {
		//@Condition注解的bean，不满足条件，不进行注入
		//在springboot核心中有讲过怎么使用@Condition，这里就不说了
		if (trackedConditionEvaluator.shouldSkip(configClass)) {
			String beanName = configClass.getBeanName();
			if (StringUtils.hasLength(beanName) && this.registry.containsBeanDefinition(beanName)) {
				this.registry.removeBeanDefinition(beanName);
			}
			this.importRegistry.removeImportingClass(configClass.getMetadata().getClassName());
			return;
		}

		if (configClass.isImported()) {
			registerBeanDefinitionForImportedConfigurationClass(configClass);
		}
		for (BeanMethod beanMethod : configClass.getBeanMethods()) {
			//将单个方法取出来
			loadBeanDefinitionsForBeanMethod(beanMethod);
		}

		loadBeanDefinitionsFromImportedResources(configClass.getImportedResources());
		loadBeanDefinitionsFromRegistrars(configClass.getImportBeanDefinitionRegistrars());
	}

	private void loadBeanDefinitionsForBeanMethod(BeanMethod beanMethod) {
		//得到配置类
		ConfigurationClass configClass = beanMethod.getConfigurationClass();
		//获取方法注解信息
		MethodMetadata metadata = beanMethod.getMetadata();
		//获取方法名称
		String methodName = metadata.getMethodName();

		//@condition ，要不要跳过
		if (this.conditionEvaluator.shouldSkip(metadata, ConfigurationPhase.REGISTER_BEAN)) {
			configClass.skippedBeanMethods.add(methodName);
			return;
		}
		if (configClass.skippedBeanMethods.contains(methodName)) {
			return;
		}

		AnnotationAttributes bean = AnnotationConfigUtils.attributesFor(metadata, Bean.class);
		Assert.state(bean != null, "No @Bean annotation attributes");

		// 处理别名
		List<String> names = new ArrayList<>(Arrays.asList(bean.getStringArray("name")));
		String beanName = (!names.isEmpty() ? names.remove(0) : methodName);

		// Register aliases even when overridden
		for (String alias : names) {
			this.registry.registerAlias(beanName, alias);
		}

		// Has this effectively been overridden before (e.g. via XML)?
		if (isOverriddenByExistingDefinition(beanMethod, beanName)) {
			if (beanName.equals(beanMethod.getConfigurationClass().getBeanName())) {
				throw new BeanDefinitionStoreException(beanMethod.getConfigurationClass().getResource().getDescription(),
						beanName, "Bean name derived from @Bean method '" + beanMethod.getMetadata().getMethodName() +
						"' clashes with bean name for containing configuration class; please make those names unique!");
			}
			return;
		}
		//创建beanDef 根据 方法返回值类型
		ConfigurationClassBeanDefinition beanDef = new ConfigurationClassBeanDefinition(configClass, metadata);
		beanDef.setResource(configClass.getResource());
		beanDef.setSource(this.sourceExtractor.extractSource(metadata, configClass.getResource()));

		if (metadata.isStatic()) {
			// static @Bean method
			beanDef.setBeanClassName(configClass.getMetadata().getClassName());
			beanDef.setFactoryMethodName(methodName);
		}
		else {
			// instance @Bean method
			beanDef.setFactoryBeanName(configClass.getBeanName());
			beanDef.setUniqueFactoryMethodName(methodName);
		}
		beanDef.setAutowireMode(AbstractBeanDefinition.AUTOWIRE_CONSTRUCTOR);
		beanDef.setAttribute(org.springframework.beans.factory.annotation.RequiredAnnotationBeanPostProcessor.
				SKIP_REQUIRED_CHECK_ATTRIBUTE, Boolean.TRUE);

		AnnotationConfigUtils.processCommonDefinitionAnnotations(beanDef, metadata);
		//进行一些设置，@bean的属性等
		Autowire autowire = bean.getEnum("autowire");
		if (autowire.isAutowire()) {
			beanDef.setAutowireMode(autowire.value());
		}

		boolean autowireCandidate = bean.getBoolean("autowireCandidate");
		if (!autowireCandidate) {
			beanDef.setAutowireCandidate(false);
		}

		String initMethodName = bean.getString("initMethod");
		if (StringUtils.hasText(initMethodName)) {
			beanDef.setInitMethodName(initMethodName);
		}

		String destroyMethodName = bean.getString("destroyMethod");
		beanDef.setDestroyMethodName(destroyMethodName);

		// Consider scoping
		ScopedProxyMode proxyMode = ScopedProxyMode.NO;
		AnnotationAttributes attributes = AnnotationConfigUtils.attributesFor(metadata, Scope.class);
		if (attributes != null) {
			beanDef.setScope(attributes.getString("value"));
			proxyMode = attributes.getEnum("proxyMode");
			if (proxyMode == ScopedProxyMode.DEFAULT) {
				proxyMode = ScopedProxyMode.NO;
			}
		}

		// Replace the original bean definition with the target one, if necessary
		BeanDefinition beanDefToRegister = beanDef;
		if (proxyMode != ScopedProxyMode.NO) {
			BeanDefinitionHolder proxyDef = ScopedProxyCreator.createScopedProxy(
					new BeanDefinitionHolder(beanDef, beanName), this.registry,
					proxyMode == ScopedProxyMode.TARGET_CLASS);
			beanDefToRegister = new ConfigurationClassBeanDefinition(
					(RootBeanDefinition) proxyDef.getBeanDefinition(), configClass, metadata);
		}

		if (logger.isTraceEnabled()) {
			logger.trace(String.format("Registering bean definition for @Bean method %s.%s()",
					configClass.getMetadata().getClassName(), beanName));
		}
		//这个方法是不是很熟悉，掉过很多次了，形成beanName和对象信息的map
		//DefaultListableBeanFactory的方法
		this.registry.registerBeanDefinition(beanName, beanDefToRegister);
	}

到此为止，所有bean都保存到了map中
key记录beanName
value记录的对象信息
注意！！！！目前为止只是将所有的bean(xml获取的，注解获取的，JAVA配置获取的)全部存到了map中，都没有进行实例化！！！