springboot启动时序概要

create(contexType)

create

registerSingleton

publish（started）

5

加载META-INF/spring.factories中的扩展实现

loader.load()

该接口职责是1.解析${}格式的文本2.从底层source中获取key的值实现类ConfigurationPropertySourcesPropertyResolver，其支持两种解析方式

registerBeanDefinition

SpringBoot版本：2.5.0 Spring版本：5.3.7

AnnotatedBeanDefinitionReader

replace SystemEnvironmentPropertySource to OriginAwareSystemEnvironmentPropertySource

7

ApplicationContextInitializer

SpringApplication

ApplicationListener

绿色类为Spring的SPI类，即可以遵循其规则，自动加载你自定义的实现类

3

load and starting(bootstrapContext)

primary bean：DemoApplicationscore注解逻辑

RandomValuePropertySourceEnvironmentPostProcessor（处理随机属性）SystemEnvironmentPropertySourceEnvironmentPostProcessor（特性增强）SpringApplicationJsonEnvironmentPostProcessor 处理SPRING_APPLICATION_JSONCloudFoundryVcapEnvironmentPostProcessorConfigDataEnvironmentPostProcessor（处理spring主配置文件+profile）DebugAgentEnvironmentPostProcessorIntegrationPropertiesEnvironmentPostProcessor 处理META-INF/spring.integration.properties

适配PropertySource的解析方式

ApplicationContextInitializedEvent

spring.main.allow-bean-definition-overriding=falsespring.main.banner-mode=offspring.main.lazy-initialization=falsespring.main.sources=com.example.demo2.config...

refresh

ConfigurationWarningsPostProcessor 用于打印错误配置的告警日志，默认会检查ComponentScan注解

注册监听器：ServerPortInfoApplicationContextInitializer ，监听事件：WebServerInitializedEvent

ConfigurableEnvironment

该事件匹配到的监听器：LoggingApplicationListener 日志框架before初始化DelegatingApplicationListener 事件转发机制（无行动）BackgroundPreinitializer 耗时操作预初始化（无行动）

shutdownHook

addBeanFactoryPostProcessor

addApplicationListener

已知的实现有：1.DelegatingApplicationContextInitializer 转发到属性context.initializer.classes指定的处理器2.SharedMetadataReaderFactoryContextInitializer 注册了一个BeanFactoryPostProcessor3.ContextIdApplicationContextInitializer cotextId处理4.ConfigurationWarningsApplicationContextInitializer 注册了一个BeanFactoryPostProcessor5.RSocketPortInfoApplicationContextInitializer 用于注册对RSocketServer初始化事件的监听器6.ServerPortInfoApplicationContextInitializer 用于注册监听器，用于打印启动端口7.ConditionEvaluationReportLoggingListener 注册监听器，监听context刷新和失败事件

listeners.contextPrepared(context)

15

BackgroundPreinitializerDelegatingApplicationListener

AnnotationConfigServletWebServerApplicationContext

load

run

这里相当于把后续事件广播的职责交给了context

14

容器准备

addLast application.properties

9

ConfigurationPropertyName解析方式是为了实现松弛绑定relaxed binding；同一个key可能有以下几种格式acme.my-project.person.first-name（推荐格式）acme.myProject.person.firstNameacme.my_project.person.first_nameACME_MYPROJECT_PERSON_FIRSTNAME

10

ApplicationStartedEvent/AvailabilityChangeEvent

处理逻辑：1.监听器如果实现了ApplicationContextAware，则注入2.所有监听器拷贝至context中

创建并关联

添加懒加载BeanFactoryPostProcessor，如果需要的话LazyInitializationBeanFactoryPostProcessor

BeanDefinitionLoader

1

ApplicationContext

ApplicationPreparedEvent

ApplicationServletEnvironment

初始阶段

该类封装了获取属性时，对属性值的类型转换逻辑比如日期绑定，字符转整型在创建时执行大量转换器的初始化

注册propertySourceRandomValuePropertySource random 处理random开头的属性

注册propertySourceStubPropertySource servletConfigInitParams 预先占坑StubPropertySource servletContextInitParams 预先占坑MutablePropertySources systemProperties java系统属性SystemEnvironmentPropertySource systemEnvironment 环境变量

AnnotationConfigUtils.registerAnnotationConfigProcessors

第二版重点

SpringBoot额外配置

LoggingApplicationListener注册单例：springBootLoggingSystem LoggingSystem注册单例：springBootLogFile LogFile注册单例：springBootLoggerGroups LoggerGroups

add

listeners.contextLoaded(context)

BackgroundPreinitializer 耗时操作异步初始化，多数是以静态方式搜索classpath路径1.ConversionServiceInitializer2.ValidationInitializer3.MessageConverterInitializer4.JacksonInitializer5.CharsetInitializer

2

11

注册单例：org.springframework.boot.context.ContextIdApplicationContextInitializer$ContextId ContextId

ConfigurableConversionService

如果1..env类型为ConfigurableEnvironment2.不存在名为configurationProperties的PropertySource则自动注册一个ConfigurationPropertySourcesPropertySource目的是适配env中所有的PropertySource统一使用ConfigurationPropertyName方式解析属性，如果解析失败，则尝试PropertySourcesPropertyResolver方式解析

contextLoaded

applyInitializers(context)

LoggingApplicationListener 日志初始化解析并设置日志相关的系统属性解析logging.file.name和logging.file.path日志group逻辑日志框架初始化

AvailabilityChangeEvent拥有状态LivenessState.CORRECT

addBefore systemProperties

ConfigurablePropertyResolver

springboot启动时序概要（第一部分）

MutablePropertySources

1.将defaultProperties移到末尾，因为默认值的优先级必须最低2.绑定spring.main属性；即拷贝env中的对应属性到SpringApplication对象中

ClassPathBeanDefinitionScanner

ApplicationReadyEvent/AvailabilityChangeEvent

环境准备

注册propertySourceDefaultPropertiesPropertySource defaultProperties 默认值机制SimpleCommandLinePropertySource commandLineArgs 启动参数

addAfter systemEnvironment

注册propertySourceOriginTrackedMapPropertySource application.properties

EnvironmentPostProcessor

create(contextType)

customizePropertySources

12

ConfigurationClassPostProcessor 扫描并注册所有@Configuration注解类AutowiredAnnotationBeanPostProcessor 处理注入逻辑，例如@AutowiredCommonAnnotationBeanPostProcessor 处理注入逻辑，例如@ResourcePersistenceAnnotationBeanPostProcessor(如果出现)EventListenerMethodProcessorDefaultEventListenerFactory

1.EnvironmentPostProcessorApplicationListener2.LoggingApplicationListener3.BackgroundPreinitializer4.DelegatingApplicationListener

initialize(ConfigurableApplicationContext)

CachingMetadataReaderFactoryPostProcessor 元素数据读取器工厂，首先将子类明确注册为优先级最高的工厂处理器。在执行工厂方法时，注册一个SharedMetadataReaderFactoryBean类型的FactoryBean，并将其关联到ConfigurationClassPostProcessor的依赖中，在ConfigurationClassPostProcessor实例化时，被注入ConcurrentReferenceCachingMetadataReaderFactory，此工厂在读取配置类元数据时发挥作用

load and postProcessEnvironment

contextPrepared(ConfigurableApplicationContext)

setId and registerSingleton

addLast

SpringApplicationRunListener

refresh阶段

13

DemoApplication

这是spring的传统关键节点，后续重点对refresh流程和自动配置实现作图

这是我个人的总结，非常适合想通过源码来探索SpringBoot特性，或者希望更容易理解源码的人查阅如果对你有所帮助的话，请给我点赞哦

6

ApplicationEnvironmentPreparedEvent

配置文件扫描位置：classpath:/classpath:/config/file:./file:./config/file:./config/*/

注册propertySource，前提是特定spring参数或者环境变量存在JsonPropertySource spring.application.json

attach

注册实例：springApplicationArguments ApplicationArgumentsspringBootBanner Banner

该事件类型匹配到以下监听器，图中仅画了重点流程，以执行顺序作为序号1.EnvironmentPostProcessorApplicationListener2.AnsiOutputApplicationListener3.LoggingApplicationListener 日志初始化4.DelegatingApplicationListener 事件转发机制5.BackgroundPreinitializer 耗时操作预初始化6.FileEncodingApplicationListener

8

create bootstrapContext and initialize

callRunners

广播ApplicationStartingEvent

EnvironmentPostProcessorApplicationListener 处理环境的扩展点AnsiOutputApplicationListenerLoggingApplicationListener 日志初始化DelegatingApplicationListener 事件转发机制BackgroundPreinitializer 耗时操作预初始化ParentContextCloserApplicationListenerClearCachesApplicationListenerFileEncodingApplicationListener

addFirst

publish（running）

AvailabilityChangeEvent拥有状态ReadinessState.ACCEPTING_TRAFFIC

4

BootstrapRegistryInitializer