=================进入getOrCreateEnvironment() private ConfigurableEnvironment getOrCreateEnvironment() { if (this.environment != null) { return this.environment; } switch (this.webApplicationType) { case SERVLET: //如果是原生servlet编程 return new StandardServletEnvironment(); case REACTIVE: //如果是响应式编程 return new StandardReactiveWebEnvironment(); default: return new StandardEnvironment(); } }====================进入configureEnvironment() protected void configureEnvironment(ConfigurableEnvironment environment, String[] args) { //给环境添加一些类型转换器 if (this.addConversionService) { ConversionService conversionService = ApplicationConversionService.getSharedInstance(); environment.setConversionService((ConfigurableConversionService) conversionService); } //加载(读取)外部配置源 //即读取所有的配置源的配置属性值 configurePropertySources(environment, args); //激活Profiles环境 configureProfiles(environment, args); } ==========进入configurePropertySources() protected void configurePropertySources(ConfigurableEnvironment environment, String[] args) { //获取到所有配置源 MutablePropertySources sources = environment.getPropertySources(); DefaultPropertiesPropertySource.ifNotEmpty(this.defaultProperties, sources::addLast); //命令行信息 if (this.addCommandLineProperties && args.length > 0) { String name = CommandLinePropertySource.COMMAND_LINE_PROPERTY_SOURCE_NAME; if (sources.contains(name)) { PropertySource source = sources.get(name); CompositePropertySource composite = new CompositePropertySource(name); composite.addPropertySource( new SimpleCommandLinePropertySource("springApplicationCommandLineArgs", args)); composite.addPropertySource(source); sources.replace(name, composite); } else { sources.addFirst(new SimpleCommandLinePropertySource(args)); } } }==============进入environmentPrepared（） void environmentPrepared(ConfigurableBootstrapContext bootstrapContext, ConfigurableEnvironment environment) { doWithListeners("spring.boot.application.environment-prepared", (listener) -> listener.environmentPrepared(bootstrapContext, environment)); }

所有配置源
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【8.2、SpringBoot启动流程--把spring应用跑起来（接8.1）】创建IOC容器 createApplicationContext()

protected ConfigurableApplicationContext createApplicationContext() { return this.applicationContextFactory.create(this.webApplicationType); } =============根据当前的应用类型（Servlet）创建容器 //当前会创建AnnotationConfigServletWebServerApplicationContext ApplicationContextFactory DEFAULT = (webApplicationType) -> { try { switch (webApplicationType) { case SERVLET: return new AnnotationConfigServletWebServerApplicationContext(); case REACTIVE: return new AnnotationConfigReactiveWebServerApplicationContext(); default: return new AnnotationConfigApplicationContext(); } } catch (Exception ex) { throw new IllegalStateException("Unable create a default ApplicationContext instance, " + "you may need a custom ApplicationContextFactory", ex); } };

准备ApplicationContext IOC容器的基本信息 prepareContext()

private void prepareContext(DefaultBootstrapContext bootstrapContext, ConfigurableApplicationContext context, ConfigurableEnvironment environment, SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) { //保存前面的基础环境 context.setEnvironment(environment); //IOC容器的后置处理流程。 postProcessApplicationContext(context); //应用初始化器：applyInitializers applyInitializers(context); listeners.contextPrepared(context); bootstrapContext.close(context); if (this.logStartupInfo) { logStartupInfo(context.getParent() == null); logStartupProfileInfo(context); } // Add boot specific singleton beans ConfigurableListableBeanFactory beanFactory = context.getBeanFactory(); beanFactory.registerSingleton("springApplicationArguments", applicationArguments); if (printedBanner != null) { beanFactory.registerSingleton("springBootBanner", printedBanner); } if (beanFactory instanceof DefaultListableBeanFactory) { ((DefaultListableBeanFactory) beanFactory) .setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding); } if (this.lazyInitialization) { context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor()); } // Load the sources Set