什么时候创建嵌入式的Servlet容器工厂？什么时候获取嵌入式的Servlet容器并启动Tomcat； 获取嵌入式的Servlet容器工厂： 1）、SpringBoot应用启动运行run方法 2）、refreshContext(context);SpringBoot刷新IOC容器【创建IOC容器对象，并初始化容器，创建容器中的每一个组件】；如果是web应用创建**AnnotationConfigEmbeddedWebApplicationContext**，否则：**AnnotationConfigApplicationContext** 3）、refresh(context);**刷新刚才创建好的ioc容器；** ```java public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // Prepare this context for refreshing. prepareRefresh(); // Tell the subclass to refresh the internal bean factory. ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // Prepare the bean factory for use in this context. prepareBeanFactory(beanFactory); try { // Allows post-processing of the bean factory in context subclasses. postProcessBeanFactory(beanFactory); // Invoke factory processors registered as beans in the context. invokeBeanFactoryPostProcessors(beanFactory); // Register bean processors that intercept bean creation. registerBeanPostProcessors(beanFactory); // Initialize message source for this context. initMessageSource(); // Initialize event multicaster for this context. initApplicationEventMulticaster(); // Initialize other special beans in specific context subclasses. onRefresh(); // Check for listener beans and register them. registerListeners(); // Instantiate all remaining (non-lazy-init) singletons. finishBeanFactoryInitialization(beanFactory); // Last step: publish corresponding event. finishRefresh(); } catch (BeansException ex) { if (logger.isWarnEnabled()) { logger.warn("Exception encountered during context initialization - " + "cancelling refresh attempt: " + ex); } // Destroy already created singletons to avoid dangling resources. destroyBeans(); // Reset 'active' flag. cancelRefresh(ex); // Propagate exception to caller. throw ex; } finally { // Reset common introspection caches in Spring's core, since we // might not ever need metadata for singleton beans anymore... resetCommonCaches(); } } } ``` 4）、 onRefresh(); web的ioc容器重写了onRefresh方法 5）、webioc容器会创建嵌入式的Servlet容器；**createEmbeddedServletContainer**(); **6）、获取嵌入式的Servlet容器工厂：** EmbeddedServletContainerFactory containerFactory = getEmbeddedServletContainerFactory(); ​ 从ioc容器中获取EmbeddedServletContainerFactory 组件；**TomcatEmbeddedServletContainerFactory**创建对象，后置处理器一看是这个对象，就获取所有的定制器来先定制Servlet容器的相关配置； 7）、**使用容器工厂获取嵌入式的Servlet容器**：this.embeddedServletContainer = containerFactory .getEmbeddedServletContainer(getSelfInitializer()); 8）、嵌入式的Servlet容器创建对象并启动Servlet容器； **先启动嵌入式的Servlet容器，再将ioc容器中剩下没有创建出的对象获取出来；** **==IOC容器启动创建嵌入式的Servlet容器==**