SpringBoot应用启动运行run方法,然后一直来到这个Run方法public ConfigurableApplicationContext run(String... args) {
StopWatch stopWatch = new StopWatch();
stopWatch.start();
ConfigurableApplicationContext context = null;
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList();this.configureHeadlessProperty();
SpringApplicationRunListeners listeners = this.getRunListeners(args);
listeners.starting();
Collection exceptionReporters;try {
ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
ConfigurableEnvironment environment = this.prepareEnvironment(listeners, applicationArguments);this.configureIgnoreBeanInfo(environment);
Banner printedBanner = this.printBanner(environment);
context = this.createApplicationContext();//创建Springboot应用程序(即ApplicationContext)，根据环境创建的exceptionReporters = this.getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[]{ConfigurableApplicationContext.class}, context);this.prepareContext(context, environment, listeners, applicationArguments, printedBanner);this.refreshContext(context);//刷新IOC容器，即创建IOC容器对象，并初始化容器，创建容器中的每一个组件(即Bean)this.afterRefresh(context, applicationArguments);
stopWatch.stop();protected ConfigurableApplicationContext createApplicationContext() {
Class<?> contextClass = this.applicationContextClass;if (contextClass == null) {try {switch(this.webApplicationType) {case SERVLET://如果是Srevlet环境就创建Servlet的SpringBoot应用contextClass = Class.forName("org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext");break;case REACTIVE:
contextClass = Class.forName("org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext");break;default:
contextClass = Class.forName("org.springframework.context.annotation.AnnotationConfigApplicationContext");
}
} catch (ClassNotFoundException var3) {throw new IllegalStateException("Unable create a default ApplicationContext, please specify an ApplicationContextClass", var3);
}
}return (ConfigurableApplicationContext)BeanUtils.instantiateClass(contextClass);
}public void refresh() throws BeansException, IllegalStateException {
Object var1 = this.startupShutdownMonitor;synchronized(this.startupShutdownMonitor) {this.prepareRefresh();
ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();this.prepareBeanFactory(beanFactory);try {this.postProcessBeanFactory(beanFactory);this.invokeBeanFactoryPostProcessors(beanFactory);this.registerBeanPostProcessors(beanFactory);this.initMessageSource();this.initApplicationEventMulticaster();this.onRefresh();//web的ioc容器重写了onRefresh方法this.registerListeners();this.finishBeanFactoryInitialization(beanFactory);this.finishRefresh();protected void onRefresh() {super.onRefresh();try {this.createWebServer();//创建嵌入式的Servlet容器，不过是先获取容器工厂，再创建容器} catch (Throwable var2) {throw new ApplicationContextException("Unable to start web server", var2);
}
}private void createWebServer() {
WebServer webServer = this.webServer;
ServletContext servletContext = this.getServletContext();if (webServer == null && servletContext == null) {
ServletWebServerFactory factory = this.getWebServerFactory();//先获取工厂从ioc容器中获取TomcatServletWebServerFactory 组件（是一个bean来的）
通过这个TomcatServletWebServerFactory创建Tomcat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；this.webServer = factory.getWebServer(new ServletContextInitializer[]{this.getSelfInitializer()});//再获取容器} else if (servletContext != null) {try {this.getSelfInitializer().onStartup(servletContext);
} catch (ServletException var4) {throw new ApplicationContextException("Cannot initialize servlet context", var4);
}
}this.initPropertySources();
}public WebServer getWebServer(ServletContextInitializer... initializers) {if (this.disableMBeanRegistry) {
Registry.disableRegistry();
}
Tomcat tomcat = new Tomcat();
File baseDir = this.baseDirectory != null ? this.baseDirectory : this.createTempDir("tomcat");
tomcat.setBaseDir(baseDir.getAbsolutePath());
Connector connector = new Connector(this.protocol);
connector.setThrowOnFailure(true);
tomcat.getService().addConnector(connector);this.customizeConnector(connector);
tomcat.setConnector(connector);
tomcat.getHost().setAutoDeploy(false);this.configureEngine(tomcat.getEngine());
Iterator var5 = this.additionalTomcatConnectors.iterator();while(var5.hasNext()) {
Connector additionalConnector = (Connector)var5.next();
tomcat.getService().addConnector(additionalConnector);
}this.prepareContext(tomcat.getHost(), initializers);return this.getTomcatWebServer(tomcat);
}protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {return new TomcatWebServer(tomcat, this.getPort() >= 0);//端口号大于0就自动启动}public TomcatWebServer(Tomcat tomcat, boolean autoStart) {this.monitor = new Object();this.serviceConnectors = new HashMap();
Assert.notNull(tomcat, "Tomcat Server must not be null");this.tomcat = tomcat;this.autoStart = autoStart;this.initialize();//启动}
嵌入式的Servlet容器创建对象并启动Servlet容器；
TomcatServletWebServerFactory是在ServletWebServerFactoryConfiguration被加入进容器的
注入之后在ServletWebServerFactoryAutoConfiguration被导入@Import({ ServletWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class,
ServletWebServerFactoryConfiguration.EmbeddedTomcat.class,//导入这个class对象 ServletWebServerFactoryConfiguration.EmbeddedJetty.class,
ServletWebServerFactoryConfiguration.EmbeddedUndertow.class })
第二步
@Configuration(proxyBeanMethods = false)//判断是否导入了Tomcat依赖，导入了就把TomcatServletWebServerFactory放入ioc容器@ConditionalOnClass({ Servlet.class, Tomcat.class, UpgradeProtocol.class })
@ConditionalOnMissingBean(value = ServletWebServerFactory.class, search = SearchStrategy.CURRENT)static class EmbeddedTomcat {
@Bean
TomcatServletWebServerFactory tomcatServletWebServerFactory(
ObjectProvider<TomcatConnectorCustomizer> connectorCustomizers,
ObjectProvider<TomcatContextCustomizer> contextCustomizers,
ObjectProvider<TomcatProtocolHandlerCustomizer<?>> protocolHandlerCustomizers) {
TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
factory.getTomcatConnectorCustomizers()
.addAll(connectorCustomizers.orderedStream().collect(Collectors.toList()));
factory.getTomcatContextCustomizers()
.addAll(contextCustomizers.orderedStream().collect(Collectors.toList()));
factory.getTomcatProtocolHandlerCustomizers()
.addAll(protocolHandlerCustomizers.orderedStream().collect(Collectors.toList())); return factory;
}
}
第三步public WebServer getWebServer(ServletContextInitializer... initializers) {if (this.disableMBeanRegistry) {
Registry.disableRegistry();
}
Tomcat tomcat = new Tomcat();//获取Tomcat//配置Tomcat基本环节File baseDir = this.baseDirectory != null ? this.baseDirectory : this.createTempDir("tomcat");
tomcat.setBaseDir(baseDir.getAbsolutePath());
Connector connector = new Connector(this.protocol);
connector.setThrowOnFailure(true);
tomcat.getService().addConnector(connector);this.customizeConnector(connector);
tomcat.setConnector(connector);
tomcat.getHost().setAutoDeploy(false);this.configureEngine(tomcat.getEngine());
Iterator var5 = this.additionalTomcatConnectors.iterator();while(var5.hasNext()) {
Connector additionalConnector = (Connector)var5.next();
tomcat.getService().addConnector(additionalConnector);
}this.prepareContext(tomcat.getHost(), initializers);return this.getTomcatWebServer(tomcat);//开始启动Tomcat}
第四步protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {return new TomcatWebServer(tomcat, this.getPort() >= 0);//端口大于0就自动启动}
第五步public TomcatWebServer(Tomcat tomcat, boolean autoStart) {this.monitor = new Object();this.serviceConnectors = new HashMap();
Assert.notNull(tomcat, "Tomcat Server must not be null");this.tomcat = tomcat;this.autoStart = autoStart;this.initialize();//准备启动}
第六步private void initialize() throws WebServerException {
logger.info("Tomcat initialized with port(s): " + this.getPortsDescription(false));
Object var1 = this.monitor;synchronized(this.monitor) {try {this.addInstanceIdToEngineName();
Context context = this.findContext();
context.addLifecycleListener((event) -> {if (context.equals(event.getSource()) && "start".equals(event.getType())) {this.removeServiceConnectors();
}
});this.tomcat.start();//启动tomcat }
@Bean//如果classpath有Tomcat就把TomcatServletWebServerFactoryCustomizer放入容器@ConditionalOnClass(name = "org.apache.catalina.startup.Tomcat")public TomcatServletWebServerFactoryCustomizer tomcatServletWebServerFactoryCustomizer(
ServerProperties serverProperties) { return new TomcatServletWebServerFactoryCustomizer(serverProperties);
}
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