start办法里的源码

public void start() throws IllegalStateException {        this.start("");    }    public void start(String taskName) throws IllegalStateException {        if (this.currentTaskName != null) {            throw new IllegalStateException("Can't start StopWatch: it's already running");        } else {            //给stopWatch对象保留一些信息            this.currentTaskName = taskName;//当前任务的名字            this.startTimeNanos = System.nanoTime();//以后的工夫        }

createBootstrapContext创立疏导上下文

private DefaultBootstrapContext createBootstrapContext() {        //创立默认的疏导上下文对象        //当前就会给外面保留很多信息        DefaultBootstrapContext bootstrapContext = new DefaultBootstrapContext();//遍历所有之前的获取到的bootstrappers，调用每一个bootstrappers的intitialize() 来实现对疏导启动器上下文环境设置        this.bootstrappers.forEach((initializer) -> initializer.intitialize(bootstrapContext));        return bootstrapContext;//null    }=============================================================public interface Bootstrapper {    /**     * Initialize the given {@link BootstrapRegistry} with any required registrations.     * @param registry the registry to initialize     *///传入疏导注册工厂//这个工厂外面能够给他退出一些以后上下文的一些疏导环境信息    void intitialize(BootstrapRegistry registry);}

让以后利用进入headless模式

private void configureHeadlessProperty() {        System.setProperty(SYSTEM_PROPERTY_JAVA_AWT_HEADLESS,                System.getProperty(SYSTEM_PROPERTY_JAVA_AWT_HEADLESS, Boolean.toString(this.headless)));    }

获取所有RunListener（运行监听器）
所谓的监听器就是监听到以后我的项目的状态

private SpringApplicationRunListeners getRunListeners(String[] args) {        Class<?>[] types = new Class<?>[] { SpringApplication.class, String[].class };//new SpringApplicationRunListeners：相当于把找到的Listener保留到SpringApplicationRunListener;        return new SpringApplicationRunListeners(logger,//getSpringFactoriesInstances: 去spring.factories找SpringApplicationRunListener                 getSpringFactoriesInstances(SpringApplicationRunListener.class, types, this, args),                this.applicationStartup);    }=====================================================SpringApplicationRunListeners(Log log, Collection<? extends SpringApplicationRunListener> listeners,            ApplicationStartup applicationStartup) {        this.log = log;        this.listeners = new ArrayList<>(listeners);        this.applicationStartup = applicationStartup;    }List<SpringApplicationRunListener> listeners;

starting（）：
遍历所有的SpringApplicationRunListener调用 starting 办法；相当于告诉所有感兴趣零碎正在启动过程的人，我的项目正在 starting。（即通知我这个我的项目正在启动）

void starting(ConfigurableBootstrapContext bootstrapContext, Class<?> mainApplicationClass) {        doWithListeners("spring.boot.application.starting", (listener) -> listener.starting(bootstrapContext),                (step) -> {                    if (mainApplicationClass != null) {                        step.tag("mainApplicationClass", mainApplicationClass.getName());                    }                });    }=========================================进入doWithListeners办法：private void doWithListeners(String stepName, Consumer<SpringApplicationRunListener> listenerAction,            Consumer<StartupStep> stepAction) {        StartupStep step = this.applicationStartup.start(stepName);        //遍历所有的listeners，当初进行到哪一步了，相当于一个事件信息        this.listeners.forEach(listenerAction);        if (stepAction != null) {            stepAction.accept(step);        }        step.end();    }================================进入this.listeners.forEach(listenerAction)：void starting(ConfigurableBootstrapContext bootstrapContext, Class<?> mainApplicationClass) {//遍历所有的SpringApplicationRunListener调用starting办法        doWithListeners("spring.boot.application.starting", (listener) -> listener.starting(bootstrapContext),                (step) -> {                    if (mainApplicationClass != null) {                        step.tag("mainApplicationClass", mainApplicationClass.getName());                    }                });    }