Spring Boot启动流程断点过程解析

setInitializers((Collection) getSpringFactoriesInstances(
  ApplicationContextInitializer.class));

/**
* Run the Spring application, creating and refreshing a new
* {@link ApplicationContext}.
* 运行一个Spring应用，创建和刷新一个新的ApplicationContext
* @param args the application arguments (usually passed from a Java main method)
* 应用参数通过java main方法传递过来
* @return a running {@link ApplicationContext}
*/
public ConfigurableApplicationContext run(String... args) {
// 任务计时器工具，可同时计数多个任务
StopWatch stopWatch = new StopWatch();
stopWatch.start();
//ApplicationContext是Spring的中心接口，为应用提供配置：1bean工厂2加载资源3注册的监听器发布事件4解析消息
ConfigurableApplicationContext context = null;
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
//headless 模式：服务器端模式，表示系统没有键盘鼠标等前端应用
configureHeadlessProperty();
//监听器容器，对run方法各个阶段事件进行监听，观察者模式
SpringApplicationRunListeners listeners = getRunListeners(args);
//监听相应的事件，SpringApplicationEvent下的一个实现
listeners.starting();
try {
//提供了对于运行SpringApplication参数的访问
ApplicationArguments applicationArguments = new DefaultApplicationArguments(
args);
//环境配置：是servlet，reactive或者java应用环境，触发evn准备好的事件
ConfigurableEnvironment environment = prepareEnvironment(listeners,
applicationArguments);
configureIgnoreBeanInfo(environment);
Banner printedBanner = printBanner(environment);
context = createApplicationContext();
exceptionReporters = getSpringFactoriesInstances(
SpringBootExceptionReporter.class,
new Class[] { ConfigurableApplicationContext.class }, context);
prepareContext(context, environment, listeners, applicationArguments,
printedBanner);
refreshContext(context);
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);
}
return context;
}