Spring BeanFactory源码学习
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一.BeanFactory
BeanFactory是Spring IOC容器的基础，是IOC容器的基础接口，所有的容器都是从它这里继承实现而来。BeanFactory提供了最基本的IOC容器的功能，即所有的容器至少需要实现的标准。BeanFactory体系结构是典型的工厂方法模式，即什么样的工厂生产什么样的产品。BeanFactory是最基本的抽象工厂，而其他的IOC容器只不过是具体的工厂，对应着各自的Bean定义方法。但同时，其他容器也针对具体场景不同，进行了扩充，提供具体的服务。
二.BeanFacory源码
1.java doc
首先是Java doc,现在阅读源码的习惯是一定要理解了java doc的描述，因为这里是作者的描述，没有人比作者更明白这个类，这个接口要干什么。
/** * The root interface for accessing a Spring bean container. * This is the basic client view of a bean container; * further interfaces such as {@link ListableBeanFactory} and * {@link org.springframework.beans.factory.config.ConfigurableBeanFactory} * are available for specific purposes. * * <p>This interface is implemented by objects that hold a number of bean definitions, * each uniquely identified by a String name. Depending on the bean definition, * the factory will return either an independent instance of a contained object * (the Prototype design pattern), or a single shared instance (a superior * alternative to the Singleton design pattern, in which the instance is a * singleton in the scope of the factory). Which type of instance will be returned * depends on the bean factory configuration: the API is the same. Since Spring * 2.0, further scopes are available depending on the concrete application * context (e.g. "request" and "session" scopes in a web environment). * * <p>The point of this approach is that the BeanFactory is a central registry * of application components, and centralizes configuration of application * components (no more do individual objects need to read properties files, * for example). See chapters 4 and 11 of "Expert One-on-One J2EE Design and * Development" for a discussion of the benefits of this approach. * * <p>Note that it is generally better to rely on Dependency Injection * ("push" configuration) to configure application objects through setters * or constructors, rather than use any form of "pull" configuration like a * BeanFactory lookup. Spring\'s Dependency Injection functionality is * implemented using this BeanFactory interface and its subinterfaces. * * <p>Normally a BeanFactory will load bean definitions stored in a configuration * source (such as an XML document), and use the {@code org.springframework.beans} * package to configure the beans. However, an implementation could simply return * Java objects it creates as necessary directly in Java code. There are no * constraints on how the definitions could be stored: LDAP, RDBMS, XML, * properties file, etc. Implementations are encouraged to support references * amongst beans (Dependency Injection). * * <p>In contrast to the methods in {@link ListableBeanFactory}, all of the * operations in this interface will also check parent factories if this is a * {@link HierarchicalBeanFactory}. If a bean is not found in this factory instance, * the immediate parent factory will be asked. Beans in this factory instance * are supposed to override beans of the same name in any parent factory. * * <p>Bean factory implementations should support the standard bean lifecycle interfaces * as far as possible. The full set of initialization methods and their standard order is:<br> * 1. BeanNameAware\'s {@code setBeanName}<br> * 2. BeanClassLoaderAware\'s {@code setBeanClassLoader}<br> * 3. BeanFactoryAware\'s {@code setBeanFactory}<br> * 4. ResourceLoaderAware\'s {@code setResourceLoader} * (only applicable when running in an application context)<br> * 5. ApplicationEventPublisherAware\'s {@code setApplicationEventPublisher} * (only applicable when running in an application context)<br> * 6. MessageSourceAware\'s {@code setMessageSource} * (only applicable when running in an application context)<br> * 7. ApplicationContextAware\'s {@code setApplicationContext} * (only applicable when running in an application context)<br> * 8. ServletContextAware\'s {@code setServletContext} * (only applicable when running in a web application context)<br> * 9. {@code postProcessBeforeInitialization} methods of BeanPostProcessors<br> * 10. InitializingBean\'s {@code afterPropertiesSet}<br> * 11. a custom init-method definition<br> * 12. {@code postProcessAfterInitialization} methods of BeanPostProcessors * * <p>On shutdown of a bean factory, the following lifecycle methods apply:<br> * 1. DisposableBean\'s {@code destroy}<br> * 2. a custom destroy-method definition
在BeanFactory里只对IOC容器的基本行为作了定义，根本不关心你的bean是如何定义怎样加载的。正如我们只关心工厂里得到什么的产品对象，至于工厂是怎么生产这些对象的，这个基本的接口不关心。
2.源码
public interface BeanFactory { /** * Used to dereference a {@link FactoryBean} instance and distinguish it from * beans <i>created</i> by the FactoryBean. For example, if the bean named * {@code myJndiObject} is a FactoryBean, getting {@code &myJndiObject} * will return the factory, not the instance returned by the factory. */ //使用转义符&来得到FactoryBean本身，用来区分通过容器获得FactoryBean本身和其产生的对象 String FACTORY_BEAN_PREFIX = "&"; //通过name来获取指定的bean Object getBean(String name) throws BeansException; //根据名字和类型来得到bean实例，增加了类型安全验证机制 <T> T getBean(String name, Class<T> requiredType) throws BeansException; //通过类型获取bean实例 <T> T getBean(Class<T> requiredType) throws BeansException; //增加更多获取的条件，同上方法 Object getBean(String name, Object... args) throws BeansException; <T> T getBean(Class<T> requiredType, Object... args) throws BeansException; //判断容器是否含有指定名字的bean boolean containsBean(String name); //查询指定名字的Bean是不是单例的Bean boolean isSingleton(String name) throws NoSuchBeanDefinitionException; //判断Bean是不是prototype类型的bean boolean isPrototype(String name) throws NoSuchBeanDefinitionException; //查询指定了名字的Bean的Class类型是否与指定类型匹配 boolean isTypeMatch(String name, Class<?> targetType) throws NoSuchBeanDefinitionException; //获取指定名字bean的Class类型 Class<?> getType(String name) throws NoSuchBeanDefinitionException; //查询指定了名字的bean的所有别名，这些别名都是在BeanDefinition中定义的 String[] getAliases(String name); }
BeanFactory接口定义了IOC容器要实现的基本方法。
三. BeanFactory 结构体系
其中BeanFactory作为最顶层的一个接口类，它定义了IOC容器的基本功能规范，BeanFactory 三个子类：ListableBeanFactory、HierarchicalBeanFactory和AutowireCapableBeanFactory。但是从上图中我们可以发现最终的默认实现类是 DefaultListableBeanFactory，他实现了所有的接口。那为何要定义这么多层次的接口呢？查阅这些接口的源码和说明发现，每个接口都有他使用的场合，它主要是为了区分在 Spring 内部在操作过程中对象的传递和转化过程中，对对象的数据访问所做的限制。例如 ListableBeanFactory 接口表示这些 Bean是可列表的，而 HierarchicalBeanFactory 表示的是这些 Bean 是有继承关系的，也就是每个Bean有可能有父Bean。AutowireCapableBeanFactory 接口定义Bean的自动装配规则。这四个接口共同定义了Bean的集合、Bean之间的关系、以 Bean行为.
1.AutowireCapableBeanFactory
1.1Java doc文档
/** * Extension of the {@link org.springframework.beans.factory.BeanFactory} * interface to be implemented by bean factories that are capable of autowiring, provided that they want to expose this functionality for * existing bean instances. * * <p>This subinterface of BeanFactory is not meant to be used in normal * application code: stick to {@link org.springframework.beans.factory.BeanFactory} * or {@link org.springframework.beans.factory.ListableBeanFactory} for * typical use cases. * * <p>Integration code for other frameworks can leverage this interface to * wire and populate existing bean instances that Spring does not control * the lifecycle of. This is particularly useful for WebWork Actions and * Tapestry Page objects, for example. * * <p>Note that this interface is not implemented by * {@link org.springframework.context.ApplicationContext} facades, * as it is hardly ever used by application code. That said, it is available * from an application context too, accessible through ApplicationContext\'s * {@link org.springframework.context.ApplicationContext#getAutowireCapableBeanFactory()} * method. * * <p>You may also implement the {@link org.springframework.beans.factory.BeanFactoryAware} * interface, which exposes the internal BeanFactory even when running in an * ApplicationContext, to get access to an AutowireCapableBeanFactory: * simply cast the passed-in BeanFactory to AutowireCapableBeanFactory. org.springframework.context.ApplicationContext#getAutowireCapableBeanFactory() */
这个工厂接口继承自BeanFacotory，它扩展了自动装配的功能，根据类定义BeanDefinition装配Bean、执行前、后处理器等。主要用它来管理ApplicationContext所不能管理的那些Bean，比如Filter，Servlet等。主要通过ApplicationContext的getAutowireCapableBeanFactory()获得实例。
1.2源码
public interface AutowireCapableBeanFactory extends BeanFactory { /** * Constant that indicates no externally defined autowiring. Note that * BeanFactoryAware etc and annotation-driven injection will still be applied. * @see #createBean * @see #autowire * @see #autowireBeanProperties */ int AUTOWIRE_NO = 0; /** * Constant that indicates autowiring bean properties by name * (applying to all bean property setters). * @see #createBean * @see #autowire * @see #autowireBeanProperties */ int AUTOWIRE_BY_NAME = 1; /** * Constant that indicates autowiring bean properties by type * (applying to all bean property setters). * @see #createBean * @see #autowire * @see #autowireBeanProperties */ int AUTOWIRE_BY_TYPE = 2; /** * Constant that indicates autowiring the greediest constructor that * can be satisfied (involves resolving the appropriate constructor). * @see #createBean * @see #autowire */ int AUTOWIRE_CONSTRUCTOR = 3; /** * Constant that indicates determining an appropriate autowire strategy * through introspection of the bean class. * @see #createBean * @see #autowire * @deprecated as of Spring 3.0: If you are using mixed autowiring strategies, * prefer annotation-based autowiring for clearer demarcation of autowiring needs. */ @Deprecated int AUTOWIRE_AUTODETECT = 4; //------------------------------------------------------------------------- // Typical methods for creating and populating external bean instances //------------------------------------------------------------------------- /** * Fully create a new bean instance of the given class. * <p>Performs full initialization of the bean, including all applicable * {@link BeanPostProcessor BeanPostProcessors}. * <p>Note: This is intended for creating a fresh instance, populating annotated * fields and methods as well as applying all standard bean initialiation callbacks. * It does <i>not</> imply traditional by-name or by-type autowiring of properties; * use {@link #createBean(Class, int, boolean)} for that purposes. * @param beanClass the class of the bean to create * @return the new bean instance * @throws BeansException if instantiation or wiring failed */ <T> T createBean(Class<T> beanClass) throws BeansException; /** * Populate the given bean instance through applying after-instantiation callbacks * and bean property post-processing (e.g. for annotation-driven injection). * <p>Note: This is essentially intended for (re-)populating annotated fields and * methods, either for new instances or for deserialized instances. It does * <i>not</i> imply traditional by-name or by-type autowiring of properties; * use {@link #autowireBeanProperties} for that purposes. * @param existingBean the existing bean instance * @throws BeansException if wiring failed */ void autowireBean(Object existingBean) throws BeansException; /** * Configure the given raw bean: autowiring bean properties, applying * bean property values, applying factory callbacks such as {@code setBeanName} * and {@code setBeanFactory}, and also applying all bean post processors * (including ones which might wrap the given raw bean). * <p>This is effectively a superset of what {@link #initializeBean} provides, * fully applying the configuration specified by the corresponding bean definition. * <b>Note: This method requires a bean definition for the given name!</b> * @param existingBean the existing bean instance * @param beanName the name of the bean, to be passed to it if necessary * (a bean definition of that name has to be available) * @return the bean instance to use, either the original or a wrapped one * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException * if there is no bean definition with the given name * @throws BeansException if the initialization failed * @see #initializeBean */ Object configureBean(Object existingBean, String beanName) throws BeansException; /** * Resolve the specified dependency against the beans defined in this factory. * @param descriptor the descriptor for the dependency * @param beanName the name of the bean which declares the present dependency * @return the resolved object, or {@code null} if none found * @throws BeansException in dependency resolution failed */ Object resolveDependency(DependencyDescriptor descriptor, String beanName) throws BeansException; //------------------------------------------------------------------------- // Specialized methods for fine-grained control over the bean lifecycle //------------------------------------------------------------------------- /** * Fully create a new bean instance of the given class with the specified * autowire strategy. All constants defined in this interface are supported here. * <p>Performs full initialization of the bean, including all applicable * {@link BeanPostProcessor BeanPostProcessors}. This is effectively a superset * of what {@link #autowire} provides, adding {@link #initializeBean} behavior. * @param beanClass the class of the bean to create * @param autowireMode by name or type, using the constants in this interface * @param dependencyCheck whether to perform a dependency check for objects * (not applicable to autowiring a constructor, thus ignored there) * @return the new bean instance * @throws BeansException if instantiation or wiring failed * @see #AUTOWIRE_NO * @see #AUTOWIRE_BY_NAME * @see #AUTOWIRE_BY_TYPE * @see #AUTOWIRE_CONSTRUCTOR */ Object createBean(Class<?> beanClass, int autowireMode, boolean dependencyCheck) throws BeansException; /** * Instantiate a new bean instance of the given class with the specified autowire * strategy. All constants defined in this interface are supported here. * Can also be invoked with {@code AUTOWIRE_NO} in order to just apply * before-instantiation callbacks (e.g. for annotation-driven injection). * <p>Does <i>not</i> apply standard {@link BeanPostProcessor BeanPostProcessors} * callbacks or perform any further initialization of the bean. This interface * offers distinct, fine-grained operations for those purposes, for example * {@link #initializeBean}. However, {@link InstantiationAwareBeanPostProcessor} * callbacks are applied, if applicable to the construction of the instance. * @param beanClass the class of the bean to instantiate * @param autowireMode by name or type, using the constants in this interface * @param dependencyCheck whether to perform a dependency check for object * references in the bean instance (not applicable to autowiring a constructor, * thus ignored there) * @return the new bean instance * @throws BeansException if instantiation or wiring failed * @see #AUTOWIRE_NO * @see #AUTOWIRE_BY_NAME * @see #AUTOWIRE_BY_TYPE * @see #AUTOWIRE_CONSTRUCTOR * @see #AUTOWIRE_AUTODETECT * @see #initializeBean * @see #applyBeanPostProcessorsBeforeInitialization * @see #applyBeanPostProcessorsAfterInitialization */ Object autowire(Class<?> beanClass, int autowireMode, boolean dependencyCheck) throws BeansException; /** * Autowire the bean properties of the given bean instance by name or type. * Can also be invoked with {@code AUTOWIRE_NO} in order to just apply * after-instantiation callbacks (e.g. for annotation-driven injection). * <p>Does <i>not</i> apply standard {@link BeanPostProcessor BeanPostProcessors} * callbacks or perform any further initialization of the bean. This interface * offers distinct, fine-grained operations for those purposes, for example * {@link #initializeBean}. However, {@link InstantiationAwareBeanPostProcessor} * callbacks are applied, if applicable to the configuration of the instance. * @param existingBean the existing bean instance * @param autowireMode by name or type, using the constants in this interface * @param dependencyCheck whether to perform a dependency check for object * references in the bean instance * @throws BeansException if wiring failed * @see #AUTOWIRE_BY_NAME * @see #AUTOWIRE_BY_TYPE * @see #AUTOWIRE_NO */ void autowireBeanProperties(Object existingBean, int autowireMode, boolean dependencyCheck) throws BeansException; /** * Apply the property values of the bean definition with the given name to * the given bean instance. The bean definition can either define a fully * self-contained bean, reusing its property values, or just property values * meant to be used for existing bean instances. * <p>This method does <i>not</i> autowire bean properties; it just applies * explicitly defined property values. Use the {@link #autowireBeanProperties} * method to autowire an existing bean instance. * <b>Note: This method requires a bean definition for the given name!</b> * <p>Does <i>not</i> apply standard {@link BeanPostProcessor BeanPostProcessors} * callbacks or perform any further initialization of the bean. This interface * offers distinct, fine-grained operations for those purposes, for example * {@link #initializeBean}. However, {@link InstantiationAwareBeanPostProcessor} * callbacks are applied, if applicable to the configuration of the instance. * @param existingBean the existing bean instance * @param beanName the name of the bean definition in the bean factory * (a bean definition of that name has to be available) * @throws org.springframework.beans.factory.NoSuchBeanDefinitionException * if there is no bean definition with the given name * @throws BeansException if applying the property values failed * @see #autowireBeanProperties */ void applyBeanPropertyValues(Object existingBean, String beanName) throws BeansException; /** * Initialize the given raw bean, applying factory callbacks * such as {@code setBeanName} and {@code setBeanFactory}, * also applying all bean post processors (including ones which * might wrap the given raw bean). * <p>Note that no bean definition of the given name has to exist * in the bean factory. The passed-in bean name will simply be used * for callbacks but not checked against the registered bean definitions. * @param existingBean the existing bean instance * @param beanName the name of the bean, to be passed to it if necessary * (only passed to {@link BeanPostProcessor BeanPostProcessors}) * @return the bean instance to use, either the original or a wrapped one * @throws BeansException if the initialization failed */ Object initializeBean(Object existingBean, String beanName) throws BeansException; /** * Apply {@link BeanPostProcessor BeanPostProcessors} to the given existing bean * instance, invoking their {@code postProcessBeforeInitialization} methods. * The returned bean instance may be a wrapper around the original. * @param existingBean the new bean instance * @param beanName the name of the bean * @return the bean instance to use, either the original or a wrapped one * @throws BeansException if any post-processing failed * @see BeanPostProcessor#postProcessBeforeInitialization */ Object applyBeanPostProcessorsBeforeInitialization(Object existingBean, String beanName) throws BeansException; /** * Apply {@link BeanPostProcessor BeanPostProcessors} to the given existing bean * instance, invoking their {@code postProcessAfterInitialization} methods. * The returned bean instance may be a wrapper around the original. * @param existingBean the new bean instance * @param beanName the name of the bean * @return the bean instance to use, either the original or a wrapped one * @throws BeansException if any post-processing failed * @see BeanPostProcessor#postProcessAfterInitialization */ Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName) throws BeansException; /** * Destroy the given bean instance (typically coming from {@link #createBean}), * applying the {@link org.springframework.beans.factory.DisposableBean} contract as well as * registered {@link DestructionAwareBeanPostProcessor DestructionAwareBeanPostProcessors}. * <p>Any exception that arises during destruction should be caught * and logged instead of propagated to the caller of this method. * @param existingBean the bean instance to destroy */ void destroyBean(Object existingBean); /** * Resolve the specified dependency against the beans defined in this factory. * @param descriptor the descriptor for the dependency * @param beanName the name of the bean which declares the present dependency * @param autowiredBeanNames a Set that all names of autowired beans (used for * resolving the present dependency) are supposed to be added to * @param typeConverter the TypeConverter to use for populating arrays and * collections * @return the resolved object, or {@code null} if none found * @throws BeansException in dependency resolution failed */ Object resolveDependency(DependencyDescriptor descriptor, String beanName, Set<String> autowiredBeanNames, TypeConverter typeConverter) throws BeansException; }
1.首先几个属性，是装配策略
AUTOWIRE_BY_NAME:根据名称记性装配。
AUTOWIRE_BY_TYPE：根据类型进行装配。
AUTOWIRE_BY_CONSTRUCT：使用构造函数进行装配。
2.重点关注两类方法
Typical methods for creating and populating external bean instances。：用于创建和填充外部bean实例的典型方法
Specialized methods for fine-grained control over the bean lifecycle。专门针对bean生命周期细粒度控制的方法
2.HierarchicalBeanFactory
2.1 JAVA DOC
package org.springframework.beans.factory; /** * Sub-interface implemented by bean factories that can be part * of a hierarchy. * * <p>The corresponding {@code setParentBeanFactory} method for bean * factories that allow setting the parent in a configurable * fashion can be found in the ConfigurableBeanFactory interface. public interface HierarchicalBeanFactory extends BeanFactory { /** * Return the parent bean factory, or {@code null} if there is none. */ BeanFactory getParentBeanFactory(); /** * Return whether the local bean factory contains a bean of the given name, * ignoring beans defined in ancestor contexts. * <p>This is an alternative to {@code containsBean}, ignoring a bean * of the given name from an ancestor bean factory. * @param name the name of the bean to query * @return whether a bean with the given name is defined in the local factory * @see BeanFactory#containsBean */ boolean containsLocalBean(String name); }
3.ListableBeanFactory
3.1JAVA DOC
/** * Extension of the {@link BeanFactory} interface to be implemented by bean factories * that can enumerate all their bean instances, rather than attempting bean lookup * by name one by one as requested by clients. BeanFactory implementations that * preload all their bean definitions (such as XML-based factories) may implement * this interface. * * <p>If this is a {@link HierarchicalBeanFactory}, the return values will <i>not</i> * take any BeanFactory hierarchy into account, but will relate only to the beans * defined in the current factory. Use the {@link BeanFactoryUtils} helper class * to consider beans in ancestor factories too. * * <p>The methods in this interface will just respect bean definitions of this factory. * They will ignore any singleton beans that have been registered by other means like * {@link org.springframework.beans.factory.config.ConfigurableBeanFactory}\'s * {@code registerSingleton} method, with the exception of * {@code getBeanNamesOfType} and {@code getBeansOfType} which will check * such manually registered singletons too. Of course, BeanFactory\'s {@code getBean} * does allow transparent access to such special beans as well. However, in typical * scenarios, all beans will be defined by external bean definitions anyway, so most * applications don\'t need to worry about this differentiation. * * <p><b>NOTE:</b> With the exception of {@code getBeanDefinitionCount} * and {@code containsBeanDefinition}, the methods in this interface * are not designed for frequent invocation. Implementations may be slow. */
总结一下：
1.从这个工厂接口开始，可以枚举列出工厂可以生产的所有实例。
2. 而且如果是一个层次继承的工厂，则只会列出当前工厂的实例，而不会列出祖先层的实例。
3.2源码
public interface ListableBeanFactory extends BeanFactory { /** * Check if this bean factory contains a bean definition with the given name. * <p>Does not consider any hierarchy this factory may participate in, * and ignores any singleton beans that have been registered by * other means than bean definitions. * @param beanName the name of the bean to look for * @return if this bean factory contains a bean definition with the given name * @see #containsBean */ boolean containsBeanDefinition(String beanName); /** * Return the number of beans defined in the factory. * <p>Does not consider any hierarchy this factory may participate in, * and ignores any singleton beans that have been registered by * other means than bean definitions. * @return the number of beans defined in the factory */ int getBeanDefinitionCount(); /** * Return the names of all beans defined in this factory. * <p>Does not consider any hierarchy this factory may participate in, * and ignores any singleton beans that have been registered by * other means than bean definitions. * @return the names of all beans defined in this factory, * or an empty array if none defined */ String[] getBeanDefinitionNames(); /** * Return the names of beans matching the given type (including subclasses), * judging from either bean definitions or the value of {@code getObjectType} * in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans, which means that FactoryBeans * will get initialized. If the object created by the FactoryBean doesn\'t match, * the raw FactoryBean itself will be matched against the type. * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils\' {@code beanNamesForTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>This version of {@code getBeanNamesForType} matches all kinds of beans, * be it singletons, prototypes, or FactoryBeans. In most implementations, the * result will be the same as for {@code getBeanNamesForType(type, true, true)}. * <p>Bean names returned by this method should always return bean names <i>in the * order of definition</i> in the backend configuration, as far as possible. * @param type the class or interface to match, or {@code null} for all bean names * @return the names of beans (or objects created by FactoryBeans) matching * the given object type (including subclasses), or an empty array if none * @since 4.2 * @see FactoryBean#getObjectType * @see BeanFactoryUtils#beanNamesForTypeIncludingAncestors(ListableBeanFactory, ResolvableType) */ String[] getBeanNamesForType(ResolvableType type); /** * Return the names of beans matching the given type (including subclasses), * judging from either bean definitions or the value of {@code getObjectType} * in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans, which means that FactoryBeans * will get initialized. If the object created by the FactoryBean doesn\'t match, * the raw FactoryBean itself will be matched against the type. * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils\' {@code beanNamesForTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>This version of {@code getBeanNamesForType} matches all kinds of beans, * be it singletons, prototypes, or FactoryBeans. In most implementations, the * result will be the same as for {@code getBeanNamesForType(type, true, true)}. * <p>Bean names returned by this method should always return bean names <i>in the * order of definition</i> in the backend configuration, as far as possible. * @param type the class or interface to match, or {@code nul以上是关于Spring BeanFactory源码学习的主要内容，如果未能解决你的问题，请参考以下文章
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