SpringBoot入门（六）----- 启动类run方法都做了什么（下）

上篇文章说SpringApplication构造方法都做了些什么，下面继续说new SpringApplication().run方法

跟源码流程图：

看一下ConfigurableApplicationContext run的代码：

    public ConfigurableApplicationContext run(String... args) {
		// 创建计时器
        StopWatch stopWatch = new StopWatch();
        stopWatch.start();
		
        ConfigurableApplicationContext context = null;
        Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList();
		// 设置属性
        this.configureHeadlessProperty();
		
		// spring中监听器的使用，这些对象想创建，就得知道监听器的全路径
		// 会从spring.factory中读取
        SpringApplicationRunListeners listeners = this.getRunListeners(args);
        listeners.starting();

        Collection exceptionReporters;
        try {
			// 初始化默认应用参数
            ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
			// 根据监听器和默认的参数 来准备spring所需要的环境
            ConfigurableEnvironment environment = this.prepareEnvironment(listeners, applicationArguments);
            this.configureIgnoreBeanInfo(environment);
			// 打印出banner
            Banner printedBanner = this.printBanner(environment);
			// 创建应用上下文
            context = this.createApplicationContext();
			// 异常报告
            exceptionReporters = this.getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[]{ConfigurableApplicationContext.class}, context);
			// 准备应用上下文	
            this.prepareContext(context, environment, listeners, applicationArguments, printedBanner);
			// 刷新上下文
            this.refreshContext(context);
			// 刷新
            this.afterRefresh(context, applicationArguments);
            stopWatch.stop();
            if (this.logStartupInfo) {
                (new StartupInfoLogger(this.mainApplicationClass)).logStarted(this.getApplicationLog(), stopWatch);
            }

            listeners.started(context);
			// 执行callRunners, 支持自定义run方法
            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);
        }
    }

然后看一下==this.refreshContext(context)==这个方法的作用：
完善了流程图

主要方法为refresh()：

    public void refresh() throws BeansException, IllegalStateException {
        synchronized(this.startupShutdownMonitor) {
			// context设置 启动日期/当前状态/初始环境/验证
            this.prepareRefresh();
			// 创建一个bean工程，
            ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
            this.prepareBeanFactory(beanFactory);

            try {
				// 注册scope 
                this.postProcessBeanFactory(beanFactory);
				// 调用所有bean工厂，对bean进行处理
                this.invokeBeanFactoryPostProcessors(beanFactory);
				// 拦截bean,
                this.registerBeanPostProcessors(beanFactory);
				// 国际化操作
                this.initMessageSource();
				// 广播事件
                this.initApplicationEventMulticaster();
				// 特殊bean 比如tomcat
                this.onRefresh();
				// 注册监听器
                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();
            }

        }
    }

然后继续跟进，流程图为：

   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);
    }

世界上有10种人，一种是懂二进制的，一种是不懂二进制的。

感谢您的收看，如有哪里写的不对 请留言，谢谢。