/** *SpringApplication */ //构造器初始化 public SpringApplication(ResourceLoader resourceLoader, Class... primarySources) { this.sources = new LinkedHashSet(); //横幅模式 OFF,CONSOLE,LOG; this.bannerMode = Mode.CONSOLE; this.logStartupInfo = true; this.addCommandLineProperties = true; this.addConversionService = true; this.headless = true; this.registerShutdownHook = true; this.additionalProfiles = new HashSet(); this.isCustomEnvironment = false; this.resourceLoader = resourceLoader; Assert.notNull(primarySources, "PrimarySources must not be null"); this.primarySources = new LinkedHashSet(Arrays.asList(primarySources)); //应用类型NONE,SERVLET,REACTIVE;存在DispatcherHandler，不存在DispatcherServlet，ServletContainer，则为REACTIVE //不存在javax.servlet.Servlet", "org.springframework.web.context.ConfigurableWebApplicationContext，则为NONE，则为SERVLET this.webApplicationType = WebApplicationType.deduceFromClasspath(); //spring.factories文件中org.springframework.context.ApplicationContextInitializer=\ //org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\ //org.springframework.boot.context.ContextIdApplicationContextInitializer,\ //org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\ //org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer this.setInitializers(this.getSpringFactoriesInstances(ApplicationContextInitializer.class)); //org.springframework.context.ApplicationListener=\ //org.springframework.boot.ClearCachesApplicationListener,\ //org.springframework.boot.builder.ParentContextCloserApplicationListener,\ //org.springframework.boot.context.FileEncodingApplicationListener,\ //org.springframework.boot.context.config.AnsiOutputApplicationListener,\ //org.springframework.boot.context.config.ConfigFileApplicationListener,\ //org.springframework.boot.context.config.DelegatingApplicationListener,\ //org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\ //org.springframework.boot.context.logging.LoggingApplicationListener,\ //org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener 进行初始化 this.setListeners(this.getSpringFactoriesInstances(ApplicationListener.class)); //推论出主类main this.mainApplicationClass = this.deduceMainApplicationClass(); } //核心开始运行 public ConfigurableApplicationContext run(String... args) { StopWatch stopWatch = new StopWatch(); stopWatch.start(); ConfigurableApplicationContext context = null; Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList(); //java.awt.headless模式 this.configureHeadlessProperty(); //开启监听 //org.springframework.boot.SpringApplicationRunListener=\ //org.springframework.boot.context.event.EventPublishingRunListener SpringApplicationRunListeners listeners = this.getRunListeners(args); listeners.starting(); Collection exceptionReporters; try { ApplicationArguments applicationArguments = new DefaultApplicationArguments(args); //环境准备 ConfigurableEnvironment environment = this.prepareEnvironment(listeners, applicationArguments); //配置系统属性spring.beaninfo.ignore this.configureIgnoreBeanInfo(environment); //打印横幅 Banner printedBanner = this.printBanner(environment); //创建ApplicationContext 根据webApplicationType //SERVLET: // contextClass = Class.forName("org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext"); //REACTIVE: // contextClass = Class.forName("org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext"); // default: // contextClass = Class.forName("org.springframework.context.annotation.AnnotationConfigApplicationContext"); /** *AnnotationConfigServletWebServerApplicationContext层级关系-》ServletWebServerApplicationContext-》GenericWebApplicationContext *-》GenericApplicationContext-》AbstractApplicationContext */ context = this.createApplicationContext(); //实例化 //# Error Reporters //org.springframework.boot.SpringBootExceptionReporter=\ //org.springframework.boot.diagnostics.FailureAnalyzers exceptionReporters = this.getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[]{ConfigurableApplicationContext.class}, context); //ApplicationContext准备 加载 this.prepareContext(context, environment, listeners, applicationArguments, printedBanner); //核心： this.refreshContext(context); this.afterRefresh(context, applicationArguments); stopWatch.stop(); if (this.logStartupInfo) { (new StartupInfoLogger(this.mainApplicationClass)).logStarted(this.getApplicationLog(), stopWatch); } listeners.started(context); this.callRunners(context, applicationArguments); } catch (Throwable var10) { this.handleRunFailure(context, var10, exceptionReporters, listeners); throw new IllegalStateException(var10); } try { listeners.running(context); return context; } catch (Throwable var9) { this.handleRunFailure(context, var9, exceptionReporters, (SpringApplicationRunListeners)null); throw new IllegalStateException(var9); } } //环境准备 private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments) { //创建环境 SERVLET StandardServletEnvironment； REACTIVE StandardReactiveWebEnvironment； StandardEnvironment ConfigurableEnvironment environment = this.getOrCreateEnvironment(); this.configureEnvironment((ConfigurableEnvironment)environment, applicationArguments.getSourceArgs()); listeners.environmentPrepared((ConfigurableEnvironment)environment); this.bindToSpringApplication((ConfigurableEnvironment)environment); if (!this.isCustomEnvironment) { environment = (new EnvironmentConverter(this.getClassLoader())).convertEnvironmentIfNecessary((ConfigurableEnvironment)environment, this.deduceEnvironmentClass()); } ConfigurationPropertySources.attach((Environment)environment); return (ConfigurableEnvironment)environment; } /** *AbstractApplicationContext */ //刷新 public void refresh() throws BeansException, IllegalStateException { Object var1 = this.startupShutdownMonitor; synchronized(this.startupShutdownMonitor) { //刷新前准备 校验 this.prepareRefresh(); //获取DefaultListableBeanFactory实例 ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory(); //beanFactory加载配置 this.prepareBeanFactory(beanFactory); try { //beanFactory后置处理，重写ApplicationContext的postProcessBeanFactory方法 this.postProcessBeanFactory(beanFactory); //核心： this.invokeBeanFactoryPostProcessors(beanFactory); //注册BeanPostProcessor this.registerBeanPostProcessors(beanFactory); this.initMessageSource(); this.initApplicationEventMulticaster(); this.onRefresh(); this.registerListeners(); this.finishBeanFactoryInitialization(beanFactory); this.finishRefresh(); } catch (BeansException var9) { if (this.logger.isWarnEnabled()) { this.logger.warn("Exception encountered during context initialization - cancelling refresh attempt: " + var9); } this.destroyBeans(); this.cancelRefresh(var9); throw var9; } finally { this.resetCommonCaches(); } } } 文章来源: https://blog.csdn.net/mufeng1007/article/details/90719957