springboot 启动流程

springboot 通过SpringApplication.run的方式启动,在启动时通过构造函数初始化容器类型

public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
        this.resourceLoader = resourceLoader;
        Assert.notNull(primarySources, "PrimarySources must not be null");
        this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));
        //获取容器类型 REACTIVE  SERVLET NONE 三种类型 一般web服务为 SERVLET 类型
        this.webApplicationType = deduceWebApplicationType();
        setInitializers((Collection) getSpringFactoriesInstances(
                ApplicationContextInitializer.class));
        setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
        this.mainApplicationClass = deduceMainApplicationClass();
    }

在SpringApplication中的 run(String… args)方法中完成spring容器的启动

    public ConfigurableApplicationContext run(String... args) {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start();
        ConfigurableApplicationContext context = null;
        Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
        configureHeadlessProperty();
        SpringApplicationRunListeners listeners = getRunListeners(args);
        listeners.starting();
        try {
            ApplicationArguments applicationArguments = new DefaultApplicationArguments(
                    args);
            //获取配置文件 准备应用中用到的参数 默认读取classPath路径下的
            //application.properties 和bootStrap.yml文件       
            ConfigurableEnvironment environment = prepareEnvironment(listeners,
                    applicationArguments);
            configureIgnoreBeanInfo(environment);

            Banner printedBanner = printBanner(environment);
            //创建spring容器的上下文
            context = createApplicationContext();
            exceptionReporters = getSpringFactoriesInstances(
                    SpringBootExceptionReporter.class,
                    new Class[] { ConfigurableApplicationContext.class }, context);
            prepareContext(context, environment, listeners, applicationArguments,
                    printedBanner);
            //刷新spring的上下文 此方法中完成bean的初始化及bean的ioc      
            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;
    }

向spring容器注册bean的调用栈
1: SpringApplication.run(String[] args) 
    =>refreshContext(context)

2: AbstractApplicationContext.refresh() 
    =>invokeBeanFactoryPostProcessors(beanFactory) 
    =>PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors())

3: PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors())
    =>invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
    =>postProcessor.postProcessBeanDefinitionRegistry(registry);

4: ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry =>processConfigBeanDefinitions(registry)
    =>parser.parse(candidates);
//扫描路径的下的文件 spring的注解的扫描 在此处完成并注册到beanFactroy中
5: ConfigurationClassParser.parse(Set<BeanDefinitionHolder> configCandidates) 
    =>parse(((AnnotatedBeanDefinition) bd).getMetadata(), holder.getBeanName());
    =>processConfigurationClass(ConfigurationClass configClass) 
    =>doProcessConfigurationClass(configClass, sourceClass)//