一.BeanFactory
BeanFactory是Spring IOC容器的鼻祖，是IOC容器的基礎(chǔ)接口，所有的容器都是從它這里繼承實現(xiàn)而來。可見其地位。BeanFactory提供了最基本的IOC容器的功能，即所有的容器至少需要實現(xiàn)的標(biāo)準(zhǔn)庆猫。
BeanFactory體系結(jié)構(gòu)是典型的工廠方法模式，即什么樣的工廠生產(chǎn)什么樣的產(chǎn)品。BeanFactory是最基本的抽象工廠猬错，而其他的IOC容器只不過是具體的工廠倦炒，對應(yīng)著各自的Bean定義方法逢唤。但同時魔慷，其他容器也針對具體場景不同，進(jìn)行了擴(kuò)充音念，提供具體的服務(wù)沪饺。
二.BeanFacory源碼
1.java doc
首先是Java doc,現(xiàn)在閱讀源碼的習(xí)慣是一定要理解了java doc的描述，因為這里是作者的描述讥脐，沒有人比作者更明白這個類遭居，這個接口要干什么啼器。
/**
* 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
概括起來：
1.BeanFactory是Spring容器的Root Interface
2.BeanFactory的作用是持有一定數(shù)量的Bean Definition，每一個都有一個獨有的String名字俱萍。BeanFactory可以返回單例或多例的對象端壳，取決于Bean定義文件。
- 通過setters,constructors進(jìn)行依賴注入更好枪蘑，其實這也是常用的方法
- BeanFactory通過載入配置源文件(XML文件)的方式损谦，來配置Bean。
- 最后一大段是BeanFactory支持的bean生命周期的順序岳颇。但是其實BeanFactory是沒有給出抽象方法的照捡。
2.源碼
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. */
//使用轉(zhuǎn)義符&來得到FactoryBean本身，用來區(qū)分通過容器獲得FactoryBean本身和其產(chǎn)生的對象
String FACTORY_BEAN_PREFIX = "&";
//這個方法是BeanFactory的主要方法话侧，通過這個方法栗精，可以取得IOC容器管理的Bean， //Bean的取得是通過指定名字索引獲取的
Object getBean(String name) throws BeansException;
//根據(jù)bean的名字和Class類型來得到bean實例掂摔，增加了類型安全驗證機制
<T> T getBean(String name, Class<T> requiredType) throws BeansException; //通過Bean類型獲取bean實例
<T> T getBean(Class<T> requiredType) throws BeansException;
//增加更多獲取的條件术羔，同上方法
Object getBean(String name, Object... args) throws BeansException; <T> T getBean(Class<T> requiredType, Object... args) throws BeansException;
//判斷容器是否含有指定名字的bean
boolean containsBean(String name);
//查詢指定名字的Bean是不是單例的Bean
boolean isSingleton(String name) throws NoSuchBeanDefinitionException;
//判斷Bean是不是prototype類型的bean
boolean isPrototype(String name) throws NoSuchBeanDefinitionException;
//查詢指定了名字的Bean的Class類型是否與指定類型匹配
boolean isTypeMatch(String name, Class<?> targetType) throws NoSuchBeanDefinitionException;
//獲取指定名字bean的Class類型
Class<?> getType(String name) throws NoSuchBeanDefinitionException;
//查詢指定了名字的bean的所有別名，這些別名都是在BeanDefinition中定義的
String[] getAliases(String name);
}
這些接口定義勾畫出了IOC容器的基本方法特性乙漓。
三. BeanFactory 結(jié)構(gòu)體系
BeanFactory作為最頂層的一個接口類级历，它定義了IOC容器的基本功能規(guī)范，BeanFactory 有三個子類接口：ListableBeanFactory叭披、HierarchicalBeanFactory 和AutowireCapableBeanFactory寥殖，還有一個實現(xiàn)類SimpleJndiBeanFactory。
所以接下來依次分析三個最有用的子接口涩蜘。
1.AutowireCapableBeanFactory 可自動裝配的Bean工廠
值得注意的是嚼贡，這個接口并沒有被ApplicationContext繼承！同诫！這個是《Spring 技術(shù)內(nèi)幕》書里寫錯的粤策。這個接口主要是管理ApplicationContext之外的Bean。
（1）java doc
/**
* 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.
Note that this interface is not implemented by
* {@link org.springframework.context.ApplicationContext} facades,
* as it is hardly ever used by application code误窖。 */
這個工廠接口繼承自BeanFacotory叮盘，它擴(kuò)展了自動裝配的功能，根據(jù)類定義BeanDefinition裝配Bean霹俺、執(zhí)行前柔吼、后處理器等。主要用它來管理ApplicationContext所不能管理的那些Bean丙唧，比如Filter愈魏，Servlet等。主要通過ApplicationContext的getAutowireCapableBeanFactory()獲得實例。
(2)源碼
/**
* Constant that indicates no externally defined autowiring. Note that
* BeanFactoryAware etc and annotation-driven injection will still be applied.
*/
int AUTOWIRE_NO = 0;
/** * Constant that indicates autowiring bean properties by name
* (applying to all bean property setters).
*/
int AUTOWIRE_BY_NAME = 1;
/** * Constant that indicates autowiring bean properties by type
* (applying to all bean property setters).
*/
int AUTOWIRE_BY_TYPE = 2;
/** * Constant that indicates autowiring the greediest constructor that
* can be satisfied (involves resolving the appropriate constructor).
*/
int AUTOWIRE_CONSTRUCTOR = 3;
/**
* Constant that indicates determining an appropriate autowire strategy
* through introspection of the bean class.
*/ @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.
*/
//通過指定的class創(chuàng)建一個全新的Bean實例
<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.
*/
//給定對象培漏，根據(jù)注釋溪厘，后處理器進(jìn)行自動裝配
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>
*/
//自動裝配Bean的屬性，應(yīng)用處理器等
Object configureBean(Object existingBean, String beanName) throws BeansException; /** * Resolve the specified dependency against the beans defined in this factory. */ 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.
* @see #AUTOWIRE_NO
* @see #AUTOWIRE_BY_NAME
* @see #AUTOWIRE_BY_TYPE
* @see #AUTOWIRE_CONSTRUCTOR */根據(jù)給定的類型北苟，指定的裝配策略桩匪，創(chuàng)建新的Bean實例
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 */
//根據(jù)給定的策略，類型友鼻，裝配Bean屬性
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.首先幾個屬性傻昙，是裝配策略
AUTOWIRE_BY_NAME ,把與Bean的屬性具有相同的名字的其他Bean自動裝配到這個屬性上。舉個栗子就是：當(dāng)有一個屬性名字為person時彩扔，則自動裝配策略選擇id為person的Bean進(jìn)行裝配妆档。
AUTOWIRE_BY_TYPE，把與Bean的屬性具有相同的類型的其他Bean自動裝配到這個屬性虫碉。
AUTOWIRE_BY_CONSTRUCT贾惦，把與bean的構(gòu)造器入?yún)⒕哂邢嗤愋偷钠渌鸅ean自動裝配到Bean構(gòu)造器的對應(yīng)參數(shù)中。
2.重點關(guān)注兩類方法
Typical methods for creating and populating external bean instances敦捧，該類是用來根據(jù)典型方法默認(rèn)創(chuàng)建Bean和裝配Bean的方法须板。
Specialized methods for fine-grained control over the bean lifecycle，該類是用來根據(jù)裝配策略細(xì)化裝配兢卵，具體控制Bean生命周期的方法习瑰。
(3)繼承體系
要注意看這個實現(xiàn)類DefaultListableBeanFactory，它的出鏡率十分高秽荤。還有ConfigureableListableBeanFactory甜奄，是他的直接子接口,實際上ConfigureableListableBeanFactory都間接或直接實現(xiàn)了這三個二級子接口。
2.HierarchicalBeanFactory 可分層次Bean工廠
(1)java doc
/**
* 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.
層次Bean工廠窃款，從這個接口開始课兄，BeanFactory有了雙親Factory，父Factory的概念晨继。
(2)源碼
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);
}
這個接口只是擴(kuò)展了兩個方法烟阐，一個是可以獲取父工廠，返回值也是BeanFactory紊扬。
另外一個方法是判斷當(dāng)前Factory是否包含給定名字的Bean曲饱，要注意的是這里只是判斷當(dāng)前工廠容器，而不管父輩珠月，祖輩工廠。這也是分層思想的體現(xiàn)楔敌。
分層繼承啤挎，從此開始。
(3)繼承體系
好吧，這里又出現(xiàn)DefaultListableBeanFactory了庆聘。
直接子接口共有兩個胜臊，一個是ApplicationContext，還有一個是ConfigurableBeanFactory伙判。
3.ListableBeanFactory 可將Bean逐一列出的Bean工廠
(1)java 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. */
總結(jié)一下：
1.從這個工廠接口開始象对，可以枚舉列出工廠可以生產(chǎn)的所有實例。
2. 而且如果是一個層次繼承的工廠宴抚，則只會列出當(dāng)前工廠的實例勒魔，而不會列出祖先層的實例。
(2)源碼
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. */
// 對于給定的名字是否含有BeanDefinition
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. */
// 返回工廠的BeanDefinition總數(shù)
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 */
// 返回工廠中所有BeanDefineition的名字
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
* @see FactoryBean#getObjectType
* @see BeanFactoryUtils#beanNamesForTypeIncludingAncestors(ListableBeanFactory, Class) */
//根據(jù)類型來返回Bean名稱菇曲，包含該層的所有Bean冠绢，包括FactoryBean
String[] getBeanNamesForType(Class<?> type); /* * 返回指定類型的名字 includeNonSingletons為false表示只取單例Bean，true則不是
* allowEagerInit為true表示立刻加載常潮，false表示延遲加載弟胀。 注意：FactoryBeans都是立刻加 載的。 */ String[] getBeanNamesForType(Class<?> type, boolean includeNonSingletons, boolean allowEagerInit); //返回對應(yīng)類型的Bean實例喊式，鍵為Bean 名稱
<T> Map<String, T> getBeansOfType(Class<T> type) throws BeansException; <T> Map<String, T> getBeansOfType(Class<T> type, boolean includeNonSingletons, boolean allowEagerInit) throws BeansException; /** * Find all names of beans whose {@code Class} has the supplied {@link Annotation}
* type, without creating any bean instances yet.
* @param annotationType the type of annotation to look for
* @return the names of all matching beans
* @since 4.0 */
//根據(jù)注解類型返回對應(yīng)的Bean名稱
String[] getBeanNamesForAnnotation(Class<? extends Annotation> annotationType); //根據(jù)注解返回對應(yīng)Bean 名稱孵户，Bean實例Map
Map<String, Object> getBeansWithAnnotation(Class<? extends Annotation> annotationType) throws BeansException; /** * Find an {@link Annotation} of {@code annotationType} on the specified
* bean, traversing its interfaces and super classes if no annotation can be
* found on the given class itself. */
//查找對應(yīng)Bean名稱，對應(yīng)注解類型的注解
<A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType) throws NoSuchBeanDefinitionException;
}
總結(jié)：
這個Bean接口總體來看是返回一組Bean名稱岔留，或者一組Bean名稱夏哭，Bean實例的Map。同時還涉及到了返回BeanDefinition的方法贸诚。
值得注意的是BeanDefinition從這里登場了開始方庭。
(3)繼承體系
又一次看到了DefaultListableBeanFactory接口。
四.整體體系結(jié)構(gòu)
是時候看看整體圖了酱固，我當(dāng)時是直接從《Spring 技術(shù)內(nèi)幕》中看到這個圖的械念，當(dāng)時就蒙圈了。現(xiàn)在整體走一遍再看运悲，可能就好一些了龄减。
可以看到的是DefaultListBeanFactory參考
具體：
1、BeanFactory作為一個主接口不繼承任何接口班眯，暫且稱為一級接口希停。
2、有3個子接口繼承了它署隘，進(jìn)行功能上的增強宠能。這3個子接口稱為二級接口。
3磁餐、ConfigurableBeanFactory可以被稱為三級接口违崇，對二級接口HierarchicalBeanFactory進(jìn)行了再次增強，它還繼承了另一個外來的接口SingletonBeanRegistry
4、ConfigurableListableBeanFactory是一個更強大的接口羞延，繼承了上述的所有接口渣淳，無所不包，稱為四級接口伴箩。
（這4級接口是BeanFactory的基本接口體系入愧。繼續(xù)，下面是繼承關(guān)系的2個抽象類和2個實現(xiàn)類：）
5嗤谚、AbstractBeanFactory作為一個抽象類棺蛛，實現(xiàn)了三級接口ConfigurableBeanFactory大部分功能。
6呵恢、AbstractAutowireCapableBeanFactory同樣是抽象類鞠值，繼承自AbstractBeanFactory，并額外實現(xiàn)了二級接口AutowireCapableBeanFactory
7渗钉、DefaultListableBeanFactory繼承自AbstractAutowireCapableBeanFactory彤恶，實現(xiàn)了最強大的四級接口ConfigurableListableBeanFactory，并實現(xiàn)了一個外來接口 BeanDefinitionRegistry鳄橘，它并非抽象類声离。
8、最后是最強大的XmlBeanFactory瘫怜，繼承自DefaultListableBeanFactory术徊，重寫了一些功能，使自己更強大鲸湃。提供了Xml文件相關(guān)BeanFactory的方法赠涮。可以讀取xml定義的BeanDefinition文件暗挑。
總結(jié)：XmlBeanFactory笋除，只是提供了最基本的IOC容器的功能。而且XMLBeanFactory,繼承自DefaultListableBeanFactory炸裆。DefaultListableBeanFactory實際包含了基本IOC容器所具有的所有重要功能垃它，是一個完整的IOC容器。
參考資料：
1.Spring：源碼解讀Spring IOC原理
2.Spring源碼分析——BeanFactory體系之接口詳細(xì)分析
- spring IOC源碼分析（1）
- 《Spring 技術(shù)內(nèi)幕》強烈推薦
