springboot启动原理

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public ConfigurableApplicationContext run(String... args) {
    StopWatch stopWatch = new StopWatch();
    stopWatch.start();
    ConfigurableApplicationContext context = null;
    FailureAnalyzers analyzers = null;
    configureHeadlessProperty();
　　　　//获取SpringApplicationRunListeners 从META-INF/spring.factories 下获取 
　　　　//SpringApplicationRunListener.class 这种类型的，并且初始化
    SpringApplicationRunListeners listeners = getRunListeners(args);  //就一个EventPunlishRunListener
    listeners.starting(); //回调所有starting方法
    try {
          ApplicationArguments applicationArguments = new DefaultApplicationArguments(args); //没有参数
          ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);
          Banner printedBanner = printBanner(environment);
　　　　　　　　//根据环境创建ioc容器
          context = createApplicationContext();
          analyzers = new FailureAnalyzers(context); //异常分析报告，下面的try{}catch{}
　　　　　　  //准备上下文环境,将环境保存到ioc容器中，applyInitializers(context);
17           prepareContext(context, environment, listeners, applicationArguments, printedBanner);
          refreshContext(context); //刷新容器，spring执行流程 相当于所有配置进入 web应用创建tomcat
          afterRefresh(context, applicationArguments);
          listeners.finished(context, null);
          stopWatch.stop();
          if (this.logStartupInfo) {
              new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
          }
          return context;
     }
      catch (Throwable ex) {
         handleRunFailure(context, listeners, analyzers, ex);
         throw new IllegalStateException(ex);
      }
 }

protected void applyInitializers(ConfigurableApplicationContext context) {
　　for (ApplicationContextInitializer initializer : getInitializers()) {
	Class<?> requiredType = GenericTypeResolver.resolveTypeArgument(initializer.getClass(), 
　　　　　　　　ApplicationContextInitializer.class);
	Assert.isInstanceOf(requiredType, context, "Unable to call initializer.");
	initializer.initialize(context); //回调之前所有initializer.initialize()
　　}
}