7_2.springboot2.x启动配置原理_2.运行run方法

矫情吗；* 2023-06-04 07:56 5阅读 0赞

**当创建完SpringApplication对象之后运行run方法**

public ConfigurableApplicationContext run(String... args) {
    		StopWatch stopWatch = new StopWatch();
    		stopWatch.start();
    		ConfigurableApplicationContext context = null;
    		Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
    		configureHeadlessProperty();
    		//获取SpringApplicationRunListener;；从类路径下META‐INF/spring.factories获取
    		SpringApplicationRunListeners listeners = getRunListeners(args);
    		//回调所有的获取SpringApplicationRunListener.starting()方法
    		listeners.starting();
    		try {
    			//封装命令行参数
    			ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
    			//准备环境
    			ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);
    			//创建环境完成后回调SpringApplicationRunListener.environmentPrepared()；表示环境准备完成
    			configureIgnoreBeanInfo(environment);
    			//控制台打印图标
    			Banner printedBanner = printBanner(environment);
    			//创建ApplicationContext；决定创建web的ioc还是普通的ioc
    			context = createApplicationContext();
    			//异常的处理
    			exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class,
    					new Class[] { ConfigurableApplicationContext.class }, context);
    			//准备上下文环境;将environment保存到ioc中；而且applyInitializers()；
                //applyInitializers()：回调之前保存的所有的ApplicationContextInitializer的initialize方法
                //回调所有的SpringApplicationRunListener的contextPrepared()；
    			prepareContext(context, environment, listeners, applicationArguments, printedBanner);
                //刷新容器；ioc容器初始化（如果是web应用还会创建嵌入式的Tomcat）
                //扫描，创建，加载所有组件的地方；（配置类，组件，自动配置）
    			refreshContext(context);
                //从ioc容器中获取所有的ApplicationRunner和CommandLineRunner进行回调
                //ApplicationRunner先回调，CommandLineRunner再回调
    			afterRefresh(context, applicationArguments);
    			stopWatch.stop();
    			if (this.logStartupInfo) {
    				new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
    			}
    			listeners.started(context);
    			callRunners(context, applicationArguments);
    		}
    		catch (Throwable ex) {
    			handleRunFailure(context, ex, exceptionReporters, listeners);
    			throw new IllegalStateException(ex);
    		}
    
    		try {
    			listeners.running(context);
    		}
    		catch (Throwable ex) {
    			handleRunFailure(context, ex, exceptionReporters, null);
    			throw new IllegalStateException(ex);
    		}
            //整个SpringBoot应用启动完成以后返回启动的ioc容器；
    		return context;
    	}

解析run方法部分代码：

**1. prepareContext(context, environment, listeners, applicationArguments, printedBanner);**

prepareContext(context, environment, listeners, applicationArguments, printedBanner)

![20191007182606425.png][]

将前面创建的SpringApplication对象中，从类路径下找到META‐INF/spring.factories配置的所有ApplicationContextInitializer的initialize方法

listeners.contextPrepared(context);
    回调所有的SpringApplicationRunListener的contextPrepared()；

**prepareContext运行完成以后回调所有的SpringApplicationRunListener的contextLoaded（）；**

[20191007182606425.png]: /images/20230601/7f0c7ff7f53f4d3faa601df4b0565622.png