spring源码解析一bean

　　学习spring源码是一件非常煎熬且很有挑战的事情，在我们日常的工作中用的最多的框架可能就是spring及其的拓展，这是一个极其庞大的家族，首先我们来先来学习spring源码，然后在它的基础上学习springmvc，springboot，springcolud等。
　　1、BeanFactory对bean的生命周期进行管理，生产各种所需要的bean供我们使用
　　BeanFactory是一个接口，它的子接口跟实现有：AnnotationConfigApplicationContext是用来管理注解bean的容器；GenericApplicationContext通用应用上下文；AnnotationConfigRegistry注解配置注册表，ListableBeanFactory根据各种条件获取bean的配置清单；ConfigurableBeanFactory提供配置factory的各种方法
　　2、BeanFactoryPostProcessor：对beanFactory进行操作更新的类；FunctionalInterfacepublicinterfaceBeanFactoryPostProcessor｛Modifytheapplicationcontextsinternalbeanfactoryafteritsstandardinitialization。Allbeandefinitionswillhavebeenloaded，butnobeanswillhavebeeninstantiatedyet。Thisallowsforoverridingoraddingpropertieseventoeagerinitializingbeans。parambeanFactorythebeanfactoryusedbytheapplicationcontextthrowsorg。springframework。beans。BeansExceptionincaseoferrorsvoidpostProcessBeanFactory（ConfigurableListableBeanFactorybeanFactory）throwsBeansException；｝
　　BeanFactoryPostProcessor就一个方法postProcessBeanFactory，看一下他的实现ConfigurationClassPostProcessorclassConfigurationClassPostProcessorimplementsBeanDefinitionRegistryPostProcessor，PriorityOrdered，ResourceLoaderAware，BeanClassLoaderAware，EnvironmentAware｛
　　ConfigurationClassPostProcessor实现了好几个接口，我们简单说一下：BeanDefinitionRegistryPostProcessor：BeanFactoryPostProcessor的子接口，在常规的BeanFactoryPostProcessor检测之前注册bean的定义信息
　　PriorityOrdered：设置优先级
　　ResourceLoaderAware：设置资源加载器，可以获取到外部资源文件
　　BeanClassLoaderAware：设置类加载器
　　EnvironmentAware：设置环境变量添加CGLIB增强处理及ImportAwareBeanPostProcessor后置处理类PreparetheConfigurationclassesforservicingbeanrequestsatruntimebyreplacingthemwithCGLIBenhancedsubclasses。OverridepublicvoidpostProcessBeanFactory（ConfigurableListableBeanFactorybeanFactory）｛intfactoryIdSystem。identityHashCode（beanFactory）；if（this。factoriesPostProcessed。contains（factoryId））｛thrownewIllegalStateException（postProcessBeanFactoryalreadycalledonthispostprocessoragainstbeanFactory）；｝this。factoriesPostProcessed。add（factoryId）；if（！this。registriesPostProcessed。contains（factoryId））｛构建和验证一个类是否被Configuration修饰，并做相关的解析工作processConfigBeanDefinitions（（BeanDefinitionRegistry）beanFactory）；｝增强配置enhanceConfigurationClasses（beanFactory）；添加后置处理类beanFactory。addBeanPostProcessor（newImportAwareBeanPostProcessor（beanFactory））；｝
　　3、BeanDefinition：bean的定义描述信息；
　　从加载配置文件后生成bean定义信息，主要就是设置类名，作用域，单例还是原型，是否懒加载等
　　4、beanPostProcessor：对初始化前后进行处理的类；
　　主要就两个方法publicinterfaceBeanPostProcessor｛初始化方法调用前要进行的处理逻辑Applythis｛codeBeanPostProcessor｝tothegivennewbeaninstanceibeforeianybeaninitializationcallbacks（likeInitializingBeans｛codeafterPropertiesSet｝oracustominitmethod）。Thebeanwillalreadybepopulatedwithpropertyvalues。Thereturnedbeaninstancemaybeawrapperaroundtheoriginal。pThedefaultimplementationreturnsthegiven｛codebean｝asis。parambeanthenewbeaninstanceparambeanNamethenameofthebeanreturnthebeaninstancetouse，eithertheoriginalorawrappedone；if｛codenull｝，nosubsequentBeanPostProcessorswillbeinvokedthrowsorg。springframework。beans。BeansExceptionincaseoferrorsseeorg。springframework。beans。factory。InitializingBeanafterPropertiesSetNullabledefaultObjectpostProcessBeforeInitialization（Objectbean，StringbeanName）throwsBeansException｛returnbean；｝在初始化方法指定后要进行的处理逻辑Applythis｛codeBeanPostProcessor｝tothegivennewbeaninstanceiafterianybeaninitializationcallbacks（likeInitializingBeans｛codeafterPropertiesSet｝oracustominitmethod）。Thebeanwillalreadybepopulatedwithpropertyvalues。Thereturnedbeaninstancemaybeawrapperaroundtheoriginal。pIncaseofaFactoryBean，thiscallbackwillbeinvokedforboththeFactoryBeaninstanceandtheobjectscreatedbytheFactoryBean（asofSpring2。0）。ThepostprocessorcandecidewhethertoapplytoeithertheFactoryBeanorcreatedobjectsorboththroughcorresponding｛codebeaninstanceofFactoryBean｝checks。pThiscallbackwillalsobeinvokedafterashortcircuitingtriggeredbya｛linkInstantiationAwareBeanPostProcessorpostProcessBeforeInstantiation｝method，incontrasttoallother｛codeBeanPostProcessor｝callbacks。pThedefaultimplementationreturnsthegiven｛codebean｝asis。parambeanthenewbeaninstanceparambeanNamethenameofthebeanreturnthebeaninstancetouse，eithertheoriginalorawrappedone；if｛codenull｝，nosubsequentBeanPostProcessorswillbeinvokedthrowsorg。springframework。beans。BeansExceptionincaseoferrorsseeorg。springframework。beans。factory。InitializingBeanafterPropertiesSetseeorg。springframework。beans。factory。FactoryBeanNullabledefaultObjectpostProcessAfterInitialization（Objectbean，StringbeanName）throwsBeansException｛returnbean；｝
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