spring boot 在什么时候启动的tomcat

我一直很好奇 spring boot 以哪种方式 启动的 tomcat 今天 特地跟踪了一下

大家都知道 spring 容器很核心的 方式 是org.springframework.context.support.AbstractApplicationContext#refresh 这个方法

其中

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();
}

调用的是 org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext#onRefresh

ps:在 springApplication.run 方法中 已jar包运行 启动的为org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext 这个上线文容器

@Override
protected void onRefresh() {
super.onRefresh();
try {
createWebServer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start web server", ex);
}
}

然后 是 org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory#getWebServer

@Override
public WebServer getWebServer(ServletContextInitializer... initializers) {
Tomcat tomcat = new Tomcat();
File baseDir = (this.baseDirectory != null ? this.baseDirectory
: createTempDir("tomcat"));
tomcat.setBaseDir(baseDir.getAbsolutePath());
Connector connector = new Connector(this.protocol);
tomcat.getService().addConnector(connector);
customizeConnector(connector);
tomcat.setConnector(connector);
tomcat.getHost().setAutoDeploy(false);
configureEngine(tomcat.getEngine());
for (Connector additionalConnector : this.additionalTomcatConnectors) {
tomcat.getService().addConnector(additionalConnector);
}
prepareContext(tomcat.getHost(), initializers);
return getTomcatWebServer(tomcat);
}