缺省配置Springboot Web应用启动过程中定义的Bean

1. ApplicationContext 对象构建时登记 6 个 bean 定义

登记时机

AnnotationConfigEmbeddedWebApplicationContext.AnnotationConfigEmbeddedWebApplicationContext
    -> new AnnotatedBeanDefinitionReader(this)
    -> AnnotatedBeanDefinitionReader.AnnotatedBeanDefinitionReader(registry,environment)
    -> AnnotationConfigUtils.registerAnnotationConfigProcessors(registry)    

1. 对于完全采用缺省配置的Springboot Web应用，其ApplicationContext的实现类最终是
   AnnotationConfigEmbeddedWebApplicationContext，该类位于包 org.springframework.boot.context.embedded。
2. 该类AnnotationConfigEmbeddedWebApplicationContext在构造函数中会创建一个AnnotatedBeanDefinitionReader对象用于读取注解方式的Bean定义。
3. 而这个类AnnotatedBeanDefinitionReader在其构造函数中，又进一步调用AnnotationConfigUtils.registerAnnotationConfigProcessors(registry) 一次性登记了6个Bean定义。

6个bean定义的名称

类名	Bean名称(共同前缀:org.springframework.context.)
ConfigurationClassPostProcessor	annotation.internalConfigurationAnnotationProcessor
AutowiredAnnotationBeanPostProcessor	annotation.internalAutowiredAnnotationProcessor
RequiredAnnotationBeanPostProcessor	annotation.internalRequiredAnnotationProcessor
CommonAnnotationBeanPostProcessor	annotation.internalCommonAnnotationProcessor
EventListenerMethodProcessor	event.internalEventListenerProcessor
DefaultEventListenerFactory	event.internalEventListenerFactory

6个bean定义的作用

类名	类型	作用简介
ConfigurationClassPostProcessor	BeanPostProcessor BeanDefinitionRegistryPostProcessor	应用启动过程中对@Configuration配置类的处理
AutowiredAnnotationBeanPostProcessor	BeanPostProcessor SmartInstantiationAwareBeanPostProcessor MergedBeanDefinitionPostProcessor PriorityOrdered	自动装配(autowire)被注解的属性，set方法或其他任意的配置方法。支持的注解 : @Autowared, @Value, JSR-330 @Inject
RequiredAnnotationBeanPostProcessor	BeanPostProcessor SmartInstantiationAwareBeanPostProcessor MergedBeanDefinitionPostProcessor PriorityOrdered	处理注解 @Required
CommonAnnotationBeanPostProcessor	BeanPostProcessor InstantiationAwareBeanPostProcessor DestructionAwareBeanPostProcessor MergedBeanDefinitionPostProcessor PriorityOrdered	支持通用Java注解,尤其是JSR-250注解,也就是javax.annotation包内的那些注解。比如 @PostConstruct, @PreDestroy,@Resource和@WebServiceRef
EventListenerMethodProcessor	SmartInitializingSingleton	将@EventListener注解的方法作为单个ApplicationListener实例注册
DefaultEventListenerFactory	EventListenerFactory Ordered	EventListenerFactory的缺省实现，支持所有常规的@EventListener注解

2.当前应用主程序登记为第7个bean定义

登记时机

	SpringApplication.run()
		->prepareContext()
		->BeanDefinitionLoader.load(Class<?>)
		->AnnotatedBeanDefinitionReader.register(Class<?>... annotatedClasses)
		->BeanDefinitionReaderUtils.registerBeanDefinition()

Bean 名字采用主程序类的短类名，也就是 application

3.登记第8个bean

登记时机

    SpringApplication.run()
		->refreshContext(applicationContext)
		->EmbeddedWebApplicationContext.refresh()
		->AbstractApplicationContext.refresh()
		->AbstractApplicationContext.invokeBeanFactoryPostProcessors(beanFactory) 
		-> PostProcessorRegistrationDelegate
		   .invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors())

这里会调用BeanFactoryPostProcessor中所有的 BeanDefinitionRegistryPostProcessor 的方法 postProcessBeanDefinitionRegistry,而 SharedMetadataReaderFactoryContextInitializer的内部类 CachingMetadataReaderFactoryPostProcessor就是这里的一个 BeanDefinitionRegistryPostProcessor, 它在执行时会注册第8个bean :

类名	Bean名称
SharedMetadataReaderFactoryBean	org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory

4.其他bean定义的添加

因为主程序上注解了 @SpringBootApplication,而这个注解隐含了另外一个注解

@SpringBootApplication 
	=> @EnableAutoConfiguration 
		=> @Import(EnableAutoConfigurationImportSelector.class)

而作为BeanDefinitionRegistryPostProcessor注册的一个ConfigurationClassPostProcessor实例被执行时，也就是其方法 processConfigBeanDefinitions() 被调用时，它会基于容器中当前的Bean集合，将这些Bean上的注解@Component,@Import,@Configuration作为线索查找更多的Bean定义，直到所有的Bean定义被登记到容器。

登记时机

    SpringApplication.run()
        ->refreshContext(applicationContext)
        ->EmbeddedWebApplicationContext.refresh()
        ->AbstractApplicationContext.refresh()
        ->AbstractApplicationContext.invokeBeanFactoryPostProcessors(beanFactory) 
        -> PostProcessorRegistrationDelegate
           .invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors())
        -> ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry()
                -> processConfigBeanDefinitions() 		
	                -> ConfigurationClassBeanDefinitionReader.loadBeanDefinitions()	

经过上面的ConfigurationClassPostProcessor的Bean定义发现，容器中又登记了102个Bean定义,Bean的总数达到110个，如下表所示 :

注册顺序	Bean名称
0	org.springframework.context.annotation.internalConfigurationAnnotationProcessor
1	org.springframework.context.annotation.internalAutowiredAnnotationProcessor
2	org.springframework.context.annotation.internalRequiredAnnotationProcessor
3	org.springframework.context.annotation.internalCommonAnnotationProcessor
4	org.springframework.context.event.internalEventListenerProcessor
5	org.springframework.context.event.internalEventListenerFactory
6	application 开发人员自己的入口主程序
7	org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory
8	sampleController 开发人员自己提供的Web控制器类
9	org.springframework.boot.autoconfigure.AutoConfigurationPackages 开发人员自己的入口主程序上隐含了注解@AutoConfigurationPackage 导致入口主程序所在包被注册为该bean
10	org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration
11	org.springframework.boot.autoconfigure.condition.BeanTypeRegistry
12	propertySourcesPlaceholderConfigurer
13	org.springframework.boot.autoconfigure.jackson. JacksonAutoConfiguration$Jackson2ObjectMapperBuilderCustomizerConfiguration
14	standardJacksonObjectMapperBuilderCustomizer
15	spring.jackson-org.springframework.boot.autoconfigure.jackson.JacksonProperties
16	org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor
17	org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.store
18	org.springframework.boot.autoconfigure.jackson. JacksonAutoConfiguration$JacksonObjectMapperBuilderConfiguration
19	jacksonObjectMapperBuilder
20	org.springframework.boot.autoconfigure.jackson. JacksonAutoConfiguration$JacksonObjectMapperConfiguration
21	jacksonObjectMapper
22	org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration
23	jsonComponentModule
24	org.springframework.boot.autoconfigure.websocket. WebSocketAutoConfiguration$TomcatWebSocketConfiguration
25	websocketContainerCustomizer
26	org.springframework.boot.autoconfigure.websocket.WebSocketAutoConfiguration
27	org.springframework.boot.autoconfigure.web. EmbeddedServletContainerAutoConfiguration$EmbeddedTomcat 嵌入式tomcat servlet容器的工厂配置类(@Configuration) 通过spring-boot-autoconfigure引入 因为spring-boot-starter-tomcat的存在被应用
28	tomcatEmbeddedServletContainerFactory 嵌入式tomcat servlet容器的工厂 通过spring-boot-autoconfigure引入 因为spring-boot-starter-tomcat的存在被应用
29	org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration 嵌入式servlet容器的自动配置类(@Configuration) 通过spring-boot-autoconfigure引入 根据实际依赖于哪个servlet容器实现包决定应用哪个servlet容器实现类
30	embeddedServletContainerCustomizerBeanPostProcessor BeanPostProcessor,用来对ConfigurableEmbeddedServletContainer应用 所有bean容器中注册的EmbeddedServletContainerCustomizer 由自动配置类EmbeddedServletContainerAutoConfiguration注册
31	errorPageRegistrarBeanPostProcessor 由自动配置类EmbeddedServletContainerAutoConfiguration注册
32	org.springframework.boot.autoconfigure.web. DispatcherServletAutoConfiguration$DispatcherServletConfiguration 用于提供dispatcherServlet bean定义 通过spring-boot-autoconfigure引入
33	dispatcherServlet SpringMVC提供的HTTP请求处理控制的集中访问点和职责派发点 由自动配置类DispatcherServletAutoConfiguration注册
34	spring.mvc-org.springframework.boot.autoconfigure.web.WebMvcProperties 外部webmvc参数对应的bean定义 由自动配置类DispatcherServletAutoConfiguration 通过注解@EnableConfigurationProperties(WebMvcProperties.class)引入
35	org.springframework.boot.autoconfigure.web. DispatcherServletAutoConfiguration$DispatcherServletRegistrationConfiguration 用于提供bean定义ServletRegistrationBean dispatcherServletRegistration 通过spring-boot-autoconfigure引入
36	dispatcherServletRegistration 用于注册dispatchServlet的ServletRegistrationBean,SCI 由自动配置类DispatcherServletAutoConfiguration注册
37	org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration 用于提供bean定义dispatcherServlet 和 ServletRegistrationBean dispatcherServletRegistration 通过spring-boot-autoconfigure引入
38	org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration
39	defaultValidator
40	methodValidationPostProcessor
41	org.springframework.boot.autoconfigure.web. ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration White label error view 的配置 spring-boot-autoconfigure ErrorMvcAutoConfiguration 的嵌套@Configuration类
42	error 一个显示错误的View模板,开发人员未指定时使用的缺省值 spring-boot-autoconfigure ErrorMvcAutoConfiguration嵌套White label error view配置类中定义的bean
43	beanNameViewResolver 从bean容器中根据bean名称找出view名称的ViewResolver，配合上面定义View bean error使用 spring-boot-autoconfigure ErrorMvcAutoConfiguration嵌套White label error view配置类中定义的bean
44	org.springframework.boot.autoconfigure.web. ErrorMvcAutoConfiguration$DefaultErrorViewResolverConfiguration 缺省错误View Resolver配置 spring-boot-autoconfigure ErrorMvcAutoConfiguration 的嵌套@Configuration类
45	conventionErrorViewResolver缺省错误View Resolver配置定义的DefaultErrorViewResolver spring-boot-autoconfigure ErrorMvcAutoConfiguration 的嵌套配置类DefaultErrorViewResolverConfiguration的Bean定义
46	org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration 自动配置通过一个MVC error控制器处理错误 通过spring-boot-autoconfigure引入
47	errorAttributes 错误属性ErrorAttributes的缺省实现，开发人员未指定时才启用这个缺省bean spring-boot-autoconfigure ErrorMvcAutoConfiguration 的Bean定义
48	basicErrorController 缺省BasicErrorController bean,基础全局错误处理Controller用于处理ErrorAttributes 开发人员未指定时才启用这个缺省baen spring-boot-autoconfigure ErrorMvcAutoConfiguration 的Bean定义
49	errorPageCustomizer 向内置Servlet容器注册一个错误页面 spring-boot-autoconfigure ErrorMvcAutoConfiguration 的Bean定义
50	preserveErrorControllerTargetClassPostProcessor
51	spring.resources-org.springframework.boot.autoconfigure.web.ResourceProperties
52	org.springframework.boot.autoconfigure.web. WebMvcAutoConfiguration$EnableWebMvcConfiguration
53	requestMappingHandlerAdapter InitializingBean,支持 @RequestMapping定义的控制器方法(HandlerMethod)
54	requestMappingHandlerMapping
55	mvcValidator
56	mvcContentNegotiationManager
57	mvcPathMatcher
58	mvcUrlPathHelper
59	viewControllerHandlerMapping
60	beanNameHandlerMapping
61	resourceHandlerMapping
62	mvcResourceUrlProvider
63	defaultServletHandlerMapping
64	mvcConversionService
65	mvcUriComponentsContributor
66	httpRequestHandlerAdapter
67	simpleControllerHandlerAdapter
68	handlerExceptionResolver
69	mvcViewResolver
70	mvcHandlerMappingIntrospector
71	org.springframework.boot.autoconfigure.web. WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter内部类FaviconConfiguration
72	faviconHandlerMapping
73	faviconRequestHandler
74	org.springframework.boot.autoconfigure.web. WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter WebMvcAutoConfigurationAdapter spring-boot-autoconfigure WebMvcAutoConfiguration的嵌套配置类
75	defaultViewResolver
76	viewResolver
77	welcomePageHandlerMapping
78	requestContextFilter 1.OrderedRequestContextFilter bean 2.将request暴露给当前线程的Servlet Filter,利用LocaleContextHolder和RequestContextHolder 3.替代方案:Spring的RequestContextListener,DispatcherServlet也会将request暴露给当前线程 4.仅在未发现有其他RequestContextFilter bean或者RequestContextListener bean定义时才定义该bean spring-boot-autoconfigure WebMvcAutoConfiguration.WebMvcAutoConfigurationAdapter定义的bean
79	org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration Web MVC 自动配置 通过spring-boot-autoconfigure引入
80	hiddenHttpMethodFilter OrderedHiddenHttpMethodFilter bean, 将post请求中实际使用的method参数转换为可以通过 HttpServletRequest.getMethod()方式访问 spring-boot-autoconfigure WebMvcAutoConfiguration的bean定义
81	httpPutFormContentFilter OrderedHttpPutFormContentFilter bean, 将PUT,PATCH请求中表单参数的获取方式处理成跟POST请求中的一样:通过getParameter*()方式访问 spring-boot-autoconfigure WebMvcAutoConfiguration的bean定义
82	org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration
83	mbeanExporter
84	objectNamingStrategy
85	mbeanServer
86	org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration
87	org.springframework.boot.autoconfigure.web. HttpMessageConvertersAutoConfiguration$StringHttpMessageConverterConfiguration
88	stringHttpMessageConverter
89	spring.http.encoding-org.springframework.boot. autoconfigure.web.HttpEncodingProperties
90	org.springframework.boot.autoconfigure.web. JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration
91	mappingJackson2HttpMessageConverter
92	org.springframework.boot.autoconfigure.web.JacksonHttpMessageConvertersConfiguration
93	org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration
94	messageConverters
95	org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration
96	spring.info-org.springframework.boot.autoconfigure.info.ProjectInfoProperties
97	org.springframework.boot.autoconfigure.web.HttpEncodingAutoConfiguration 配置Web应用中使用的字符编码方式 1.如果characterEncodingFilter bean不存在则增加一个 2.如果localeCharsetMappingsCustomizer bean未被定义则添加一个 3.参数前缀 spring.http.encoding,对应属性类 HttpEncodingProperties(缺省字符集是UTF-8) 通过spring-boot-autoconfigure引入
98	characterEncodingFilter 1.Filter bean 2.设置理解request数据使用的字符集的Servlet Filter spring-boot-autoconfigure HttpEncodingAutoConfiguration定义的bean
99	localeCharsetMappingsCustomizer EmbeddedServletContainerCustomizer bean设置容器针对不同的Locale使用哪种编码方式 spring-boot-autoconfigure HttpEncodingAutoConfiguration定义的bean
100	org.springframework.boot.autoconfigure.web.MultipartAutoConfiguration multi-part upload文件上传的自动配置 1.如果StandardServletMultipartResolver不存在则增加一个 2.如果MultipartConfigElement未被定义则添加一个 3.缺省情况下,EmbeddedWebApplicationContext会关联这个MultipartConfigElement 到任意一个Servlet bean用于处理文件上传 4.javax.servlet.MultipartConfigElement是用于配置容器如何处理文件上传的Servlet API 5.参数前缀 spring.http.multipart,对应属性类 MultipartProperties 通过spring-boot-autoconfigure引入
101	multipartConfigElement 容器如何处理文件上传的配置 spring-boot-autoconfigure MultipartAutoConfiguration定义的bean
102	multipartResolver 1.一个StandardServletMultipartResolver实例bean 2.会被作为一个multipartResolver添加到一个Spring DispatcherServlet context 3.基于Servlet 3.0 javax.servlet.http.Part API spring-boot-autoconfigure MultipartAutoConfiguration定义的bean
103	spring.http.multipart-org.springframework.boot.autoconfigure.web.MultipartProperties
104	org.springframework.boot.autoconfigure.web.ServerPropertiesAutoConfiguration 提供配置内置servlet容器ConfigurableEmbeddedServletContainer的bean ServerProperties 通过spring-boot-autoconfigure引入
105	serverProperties EmbeddedServletContainerCustomizer web服务器的ConfigurationProperties，比如端口和路径设置， 被用来设置ConfigurableEmbeddedServletContainer的属性， 被应用时会向ConfigurableEmbeddedServletContainer添加两个SCI : SessionConfiguringInitializer InitParameterConfiguringServletContextInitializer 通过spring-boot-autoconfigure引入 由自动配置类ServerPropertiesAutoConfiguration注册
106	duplicateServerPropertiesDetector EmbeddedServletContainerCustomizer 确保应用上下文中只有一个ServerProperties 通过spring-boot-autoconfigure引入 由自动配置类ServerPropertiesAutoConfiguration注册
107	org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration$RestTemplateConfiguration
108	restTemplateBuilder
109	org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration

相关资料

Spring ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry() 是如何工作的 ?

Spring 工具类 ConfigurationClassParser 是如何工作的 ？

Spring boot web 应用 Bean介绍 : AutoConfigurationPackages

SpringApplication 的启动过程的两个阶段