SpringIOC——refresh()

一、refresh()方法

使用模板方法模式定义的一个顶级抽象父类，方法具体实现延迟到子类 ，每一个方法都是一个钩子，可以被子类重写。

    @Override
    public void refresh() throws BeansException, IllegalStateException {
        synchronized (this.startupShutdownMonitor) {
            // ② IOC初始化前的装备(配置环境参数、创建监听器、事件容器)
            prepareRefresh();

            // ③ 这里可以分为两类：
            // GenericApplicationContext: 仅仅是控制beanfactory不能重复refresh
            // AbstractRefreshableApplicationContext：允许重复refresh，销毁就beanfactory，创建新beanfactory并且重新扫描生成beanDefinitionMap容器。

            ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

            // ④ 设置beanfactory的一些属性（bean的类加载器、忽略接口、BeanPostProcessor、环境参数单例注册到beanfactory单例容器中）
            prepareBeanFactory(beanFactory);

            try {
                // ⑤空方法，留由子类实现。
                //例如注册servlet相关的忽略接口、beanPostProcessor、各作用域生成bean的bean工厂
                //注册servlet的一些单例（servletContext/servletConfig/contextparameters/contextAttributes）到beanfactory的单例容器中
                postProcessBeanFactory(beanFactory);

                // ⑥beanFactoryPostProcessor排序并依次调用
                // beanFactoryPostProcessor：beanfactory的后置处理器，可以理解为一个beanfactory的拦截器（实例化后需要执行的自定义操作)
                // 例如：beanfactory初始化完成后，修改忽略接口、甚至可以对特定的beandefinition做修改
                invokeBeanFactoryPostProcessors(beanFactory);

                // ⑦BeanPostProcessors排序并依次注册到beanfactory的beanpostProcessor容器中
                // beanPostProcessors：bean实例化的处理器，可以理解为一个bean的拦截器（实例化前+实例化后需要执行自定义操作)
                // 例如：bean单例化前，修改beandefinition的属性。
                //实例化后DI，
                //拦截getbean()拦截返回一个代理类bean
                registerBeanPostProcessors(beanFactory);

                // ⑧初始化国际化文件，支持国际化
                initMessageSource();

                // ⑨初始化时间监听器并注册到beanfactory的单例容器中
                initApplicationEventMulticaster();

                // ⑩空方法，子类实现，初始化一些自定义bean并注册到beanfactory的单例容器中
                //  例如：themeSource，支持主题切换
                onRefresh();

                // ⑪注册个中监听器到beanfactory指定容器中
                registerListeners();

                // ⑫实例化不需要延迟加载的所有单例类型的bean（scope = singleton）
                finishBeanFactoryInitialization(beanFactory);

                // ⑬容器初始化完成，触发各种事件监控,ApplicationListener.onApplicationEvent()的执行时机（dubbo注册就是在这里实现的）
                // 例如：beanfactory的生命周期监控
                finishRefresh();
            }

            catch (BeansException ex) {
                if (logger.isWarnEnabled()) {
                    logger.warn("Exception encountered during context initialization - " +
                            "cancelling refresh attempt: " + ex);
                }

                // ⑭ 容器初始化失败，销毁所有已实例化的bean
                destroyBeans();

                // ⑮ 设置active = false
                cancelRefresh(ex);

                // Propagate exception to caller.
                throw ex;
            }

            finally {
                // ⑯ 清空公共的反射缓存
                resetCommonCaches();
            }
        }
    }  

① 加锁：也是SpringIOC中主要加锁方式

    private final Object startupShutdownMonitor = new Object();
    @Override
    public void refresh() throws BeansException, IllegalStateException {
        synchronized (this.startupShutdownMonitor) {
                    ...
                }
        }

利用synchronized实现的一个细粒度锁。拥有ReentranLock.lock()的细粒度，还不用释放unlock()。

② prepareRefresh()：IOC容器初始化之前的准备（配置环境参数，创建监听器容器，创建事件容器）

    protected void prepareRefresh() {
        // 容器开始时间+容器关闭开启状态
        this.startupDate = System.currentTimeMillis();
        this.closed.set(false);
        this.active.set(true);

        if (logger.isDebugEnabled()) {
            if (logger.isTraceEnabled()) {
                logger.trace("Refreshing " + this);
            }
            else {
                logger.debug("Refreshing " + getDisplayName());
            }
        }

        //初始化IOC容器的一些环境参数，默认空方法，子类可重写
        //这里可以先创建一个标准环境变量StandardEnvironment，然后设置一些环境参数
        //并且指定一些必须配置的参数
        initPropertySources();

        //若未创建，则创建一个标准环境变量StandardEnvironment
        //校验上面指定的必须配置的参数是否已经配置，没有配置会抛出异常
        getEnvironment().validateRequiredProperties();

        // 配置一些refresh()之前的监听器
        if (this.earlyApplicationListeners == null) {
            this.earlyApplicationListeners = new LinkedHashSet<>(this.applicationListeners);
        }
        else {
            // Reset local application listeners to pre-refresh state.
            this.applicationListeners.clear();
            this.applicationListeners.addAll(this.earlyApplicationListeners);
        }

        //创建是一个事件集合
        this.earlyApplicationEvents = new LinkedHashSet<>();
    }

③ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory()：控制refresh调用次数。

    protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
        //抽象方法,控制IOC容器的refresh()次数
        //仅允许refresh()一次,再次刷新会报错：GenericApplicationContext.java
        //允许重复刷新()：AbstractRefreshableApplicationContext.java ，
        //刷新逻辑是销毁旧beanfactory，实例化一个新的beanfactory;当然没有旧beanfactory这里会直接实例化一个beanfactory
        //并且重新扫描生成beanDefinitionMap容器
        refreshBeanFactory();
        //抽象方法
        //返回容器类ApplicationContext创建时创建的DefaultListableBeanFactory实例
        return getBeanFactory();
    }

    /* org/springframework/context/support/AbstractRefreshableApplicationContext.java:129 */
    protected final void refreshBeanFactory() throws BeansException {
        if (hasBeanFactory()) {
            //允许重复刷新，销毁旧beanfactory
            destroyBeans();
            closeBeanFactory();
        }
        try {
            //创建新的beanfactory
            //传统的基于xml解析的ApplicationContext，例如spring2.x经常拿来学习的ClassPathXmlApplitionContext.java
            //beanfactory是在这里实例化的，而不是在applicationContext的构造方法中
            DefaultListableBeanFactory beanFactory = createBeanFactory();
            beanFactory.setSerializationId(getId());
            customizeBeanFactory(beanFactory);
            //重新扫描生成beandefinitionMap容器
            loadBeanDefinitions(beanFactory);
            synchronized (this.beanFactoryMonitor) {
                this.beanFactory = beanFactory;
            }
        }
        catch (IOException ex) {
            throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
        }
    }      

④prepareBeanFactory(beanFactory)：设置DefaultListableBeanFactory实例的属性（类加载器，忽略接口，BeanPostProcessor，将环境变量单例注册到beanfactory中）

    protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        // Tell the internal bean factory to use the context's class loader etc.
        //设置类加载器
        beanFactory.setBeanClassLoader(getClassLoader());
        beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
        beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

        // Configure the bean factory with context callbacks.
        //设置BeanPostProcessor（后置处理器）
        beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
        //设置需要忽略的接口,这些接口的实现类不会被IOC容器实例化
        beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
        beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
        beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
        beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
        beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
        beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);

        // BeanFactory interface not registered as resolvable type in a plain factory.
        // MessageSource registered (and found for autowiring) as a bean.
        //beanfactory接口不能注册为一个简单工厂的解析类型
        //自动转配bean
        beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
        beanFactory.registerResolvableDependency(ResourceLoader.class, this);
        beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
        beanFactory.registerResolvableDependency(ApplicationContext.class, this);

        // Register early post-processor for detecting inner beans as ApplicationListeners.
        //设置BeanPostProcessor后置处理器
        beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

        // Detect a LoadTimeWeaver and prepare for weaving, if found.
        if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
            beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
            // Set a temporary ClassLoader for type matching.
            beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
        }
//将环境单例StandardEnvironment注册到beanfactory单例容器中
        if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
            beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
        }
        if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
            beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
        }
        if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
            beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
        }
    }

⑤postProcessBeanFactory(beanFactory)：抽象方法，子类具体实现

选取AnnotationConfigApplication的父类GenericWebApplicationContext：

将serlvet相关的后置处理器、作用域类型、servlet的bean的创建工厂设置到beanfactory中

将serlvet的servletContext、servletConfig、contextParameters、contexAttributes注册到beanfactory的单例容器中

    protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        if (this.servletContext != null) {
            //注册servletContext相关处理器
            //忽略servletContext相关的接口
            beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext));
            beanFactory.ignoreDependencyInterface(ServletContextAware.class);
        }
        //注册beanfactory的servlet的三个作用域实例，并指定servlet相关类型的bean的创建工厂
        WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);
        //servletContex、servletConfig、contextParameters、contextAttributes实例注册到beanfactory的单例容器中
        WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext);
    }

    /* WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext); */
    public static void registerWebApplicationScopes(ConfigurableListableBeanFactory beanFactory,
            @Nullable ServletContext sc) {
        //注册servlet作用域 request session
        //request:一个请求创建一个request
        //session:一次会话创建一个session
        beanFactory.registerScope(WebApplicationContext.SCOPE_REQUEST, new RequestScope());
        beanFactory.registerScope(WebApplicationContext.SCOPE_SESSION, new SessionScope());
        if (sc != null) {
            //注册servlet作用域 application
            //application：所有用户共享
            ServletContextScope appScope = new ServletContextScope(sc);
            beanFactory.registerScope(WebApplicationContext.SCOPE_APPLICATION, appScope);
            // Register as ServletContext attribute, for ContextCleanupListener to detect it.
            sc.setAttribute(ServletContextScope.class.getName(), appScope);
        }
        //注册对应类型的实例工厂
        beanFactory.registerResolvableDependency(ServletRequest.class, new RequestObjectFactory());
        beanFactory.registerResolvableDependency(ServletResponse.class, new ResponseObjectFactory());
        beanFactory.registerResolvableDependency(HttpSession.class, new SessionObjectFactory());
        beanFactory.registerResolvableDependency(WebRequest.class, new WebRequestObjectFactory());
        if (jsfPresent) {
            FacesDependencyRegistrar.registerFacesDependencies(beanFactory);
        }
    }

    /* WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext); */
    public static void registerEnvironmentBeans(ConfigurableListableBeanFactory bf,
            @Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {
        //将servletContext实例注册到beanfactory单例容器中
        if (servletContext != null && !bf.containsBean(WebApplicationContext.SERVLET_CONTEXT_BEAN_NAME)) {
            bf.registerSingleton(WebApplicationContext.SERVLET_CONTEXT_BEAN_NAME, servletContext);
        }

        //将servletConfig实例注册到beanfactory单例容器中
        if (servletConfig != null && !bf.containsBean(ConfigurableWebApplicationContext.SERVLET_CONFIG_BEAN_NAME)) {
            bf.registerSingleton(ConfigurableWebApplicationContext.SERVLET_CONFIG_BEAN_NAME, servletConfig);
        }

        //将contextParameters转化成一个Map注册到beanfactory的单例容器中
        if (!bf.containsBean(WebApplicationContext.CONTEXT_PARAMETERS_BEAN_NAME)) {
            Map<String, String> parameterMap = new HashMap<>();
            if (servletContext != null) {
                Enumeration<?> paramNameEnum = servletContext.getInitParameterNames();
                while (paramNameEnum.hasMoreElements()) {
                    String paramName = (String) paramNameEnum.nextElement();
                    parameterMap.put(paramName, servletContext.getInitParameter(paramName));
                }
            }
            if (servletConfig != null) {
                Enumeration<?> paramNameEnum = servletConfig.getInitParameterNames();
                while (paramNameEnum.hasMoreElements()) {
                    String paramName = (String) paramNameEnum.nextElement();
                    parameterMap.put(paramName, servletConfig.getInitParameter(paramName));
                }
            }
            bf.registerSingleton(WebApplicationContext.CONTEXT_PARAMETERS_BEAN_NAME,
                    Collections.unmodifiableMap(parameterMap));
        }

        //将contextAttributes转化成Map注册到beanfactory的单例容器中
        if (!bf.containsBean(WebApplicationContext.CONTEXT_ATTRIBUTES_BEAN_NAME)) {
            Map<String, Object> attributeMap = new HashMap<>();
            if (servletContext != null) {
                Enumeration<?> attrNameEnum = servletContext.getAttributeNames();
                while (attrNameEnum.hasMoreElements()) {
                    String attrName = (String) attrNameEnum.nextElement();
                    attributeMap.put(attrName, servletContext.getAttribute(attrName));
                }
            }
            bf.registerSingleton(WebApplicationContext.CONTEXT_ATTRIBUTES_BEAN_NAME,
                    Collections.unmodifiableMap(attributeMap));
        }
    }

 ⑥ invokeBeanFactoryPostProcessors(beanFactory)：需要与上面的BeanPostProcessors区分开，主要是区分两类PostProcessor，然后对bean相关的postjProcessor实例按照优先级排序，按照优先级顺序调用。

BeanPostProcessors：处理特定的bean的后置处理器，（bean实例化的拦截器）

BeanFactoryPostProcessors：处理beanfactory下所有bean的后置处理器

    protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
        //这个方法很长有点复杂
        //1、具体beanfactory中后置处理器beanFactoryPostProcessor分为两类
        //①bean注册相关的后置处理器:BeanDefinitionRegistryPostProcessors
        //②普通后置处理器
        //2、将上面①中后置处理器按照优先级逐一调用
        //①实现PriorityOrdered接口的
        //②实现Ordered接口的
        //③其他BeanDefinitionRegistryPostProcessors
        PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());

        // Detect a LoadTimeWeaver and prepare for weaving, if found in the meantime
        // (e.g. through an @Bean method registered by ConfigurationClassPostProcessor)
        //目前还不清楚loadTimeWeaver的作用
        if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
            beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
            beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
        }
    }

 ⑦ registerBeanPostProcessors(beanFactory)：其实内容跟上面⑥差不多，只是处理对象不同了。beanPostProcessor实例按照优先级顺序注册到beanfactory的beanpostprocessor容器中。

a 实现PriorityOrdered接口的

b 实现Ordered接口的，未实现MergedBeanDefinitionPostProcessor接口的

c 剩下的未实现MergedBeanDefinitionPostProcessor接口的

d 实现MergedBeanDefinitionPostProcessor接口的

e 提供一个末位动态注册器，可从bean单例中拉取监听器到末尾

    public static void registerBeanPostProcessors(
            ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {

        String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);

        // Register BeanPostProcessorChecker that logs an info message when
        // a bean is created during BeanPostProcessor instantiation, i.e. when
        // a bean is not eligible for getting processed by all BeanPostProcessors.
        //获取所有beanProcessor，并注册一个记录beanProcessor数量的BeanPostProcessor
        int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
        beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

        // 将beanPostProcessor区分为四类类然后按此顺序注册到beanfactory中
        // 实现PriorityOrdered接口的
        // 实现Ordered接口的，未实现MergedBeanDefinitionPostProcessor接口的
        // 剩下的未实现MergedBeanDefinitionPostProcessor接口的
        // 实现MergedBeanDefinitionPostProcessor接口的
        List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
        List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
        List<String> orderedPostProcessorNames = new ArrayList<>();
        List<String> nonOrderedPostProcessorNames = new ArrayList<>();
        for (String ppName : postProcessorNames) {
            if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
                BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
                priorityOrderedPostProcessors.add(pp);
                if (pp instanceof MergedBeanDefinitionPostProcessor) {
                    internalPostProcessors.add(pp);
                }
            }
            else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
                orderedPostProcessorNames.add(ppName);
            }
            else {
                nonOrderedPostProcessorNames.add(ppName);
            }
        }

        // First, register the BeanPostProcessors that implement PriorityOrdered.
        //将实现PriorityOrdered接口的先排序，后注册
        sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
        registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

        // Next, register the BeanPostProcessors that implement Ordered.
        //将实现Ordered接口的，排序注册
        List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
        for (String ppName : orderedPostProcessorNames) {
            BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
            orderedPostProcessors.add(pp);
            if (pp instanceof MergedBeanDefinitionPostProcessor) {
                internalPostProcessors.add(pp);
            }
        }
        sortPostProcessors(orderedPostProcessors, beanFactory);
        registerBeanPostProcessors(beanFactory, orderedPostProcessors);

        // Now, register all regular BeanPostProcessors.
        //将剩余的，后注册
        List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
        for (String ppName : nonOrderedPostProcessorNames) {
            BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
            nonOrderedPostProcessors.add(pp);
            if (pp instanceof MergedBeanDefinitionPostProcessor) {
                internalPostProcessors.add(pp);
            }
        }
        registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);

        // Finally, re-register all internal BeanPostProcessors.
        //将实现MergedBeanDefinitionPostProcessor接口重新注册（原来注册过的会删除后，再注册，所以优先级比上面三种低）
        sortPostProcessors(internalPostProcessors, beanFactory);
        registerBeanPostProcessors(beanFactory, internalPostProcessors);

        // 注册一个末尾的处理器，可以实现，动态将bean单例中的applicationContextListener注册到末尾（优先级最低）
        beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
    }

 ⑧ initMessageSource()：国际化支持，注册一个new DelegatingMessageSource()到beanfactory的单例容器中，支持继承关系

    protected void initMessageSource() {
        ConfigurableListableBeanFactory beanFactory = getBeanFactory();
        //国际化支持，支持继承关系
        if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
            this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
            // Make MessageSource aware of parent MessageSource.
            if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {
                HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
                if (hms.getParentMessageSource() == null) {
                    // Only set parent context as parent MessageSource if no parent MessageSource
                    // registered already.
                    hms.setParentMessageSource(getInternalParentMessageSource());
                }
            }
            if (logger.isTraceEnabled()) {
                logger.trace("Using MessageSource [" + this.messageSource + "]");
            }
        }
        else {
            // Use empty MessageSource to be able to accept getMessage calls.
            DelegatingMessageSource dms = new DelegatingMessageSource();
            dms.setParentMessageSource(getInternalParentMessageSource());
            this.messageSource = dms;
            beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);
            if (logger.isTraceEnabled()) {
                logger.trace("No '" + MESSAGE_SOURCE_BEAN_NAME + "' bean, using [" + this.messageSource + "]");
            }
        }
    }

⑨ initApplicationEventMulticaster()：注册一个applicationEvent多路广播器到beanfactory的单例容器中

    protected void initApplicationEventMulticaster() {
        ConfigurableListableBeanFactory beanFactory = getBeanFactory();
        // 初始化一个applicationEvent多路广播，具体作用未知
        if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
            this.applicationEventMulticaster =
                    beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
            if (logger.isTraceEnabled()) {
                logger.trace("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
            }
        }
        else {
            this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
            beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
            if (logger.isTraceEnabled()) {
                logger.trace("No '" + APPLICATION_EVENT_MULTICASTER_BEAN_NAME + "' bean, using " +
                        "[" + this.applicationEventMulticaster.getClass().getSimpleName() + "]");
            }
        }
    }

 ⑩ onrefresh()：空方法，初始化一些特殊的bean。

AnnotationConfigApplicationContext：创建themeSource，主题资源注册

        protected void onRefresh() {
            this.themeSource = UiApplicationContextUtils.initThemeSource(this);
        }

        public static ThemeSource initThemeSource(ApplicationContext context) {
        if (context.containsLocalBean(THEME_SOURCE_BEAN_NAME)) {
            ThemeSource themeSource = context.getBean(THEME_SOURCE_BEAN_NAME, ThemeSource.class);
            // Make ThemeSource aware of parent ThemeSource.
            if (context.getParent() instanceof ThemeSource && themeSource instanceof HierarchicalThemeSource) {
                HierarchicalThemeSource hts = (HierarchicalThemeSource) themeSource;
                if (hts.getParentThemeSource() == null) {
                    // Only set parent context as parent ThemeSource if no parent ThemeSource
                    // registered already.
                    hts.setParentThemeSource((ThemeSource) context.getParent());
                }
            }
            if (logger.isDebugEnabled()) {
                logger.debug("Using ThemeSource [" + themeSource + "]");
            }
            return themeSource;
        }
        else {
            // Use default ThemeSource to be able to accept getTheme calls, either
            // delegating to parent context's default or to local ResourceBundleThemeSource.
            HierarchicalThemeSource themeSource = null;
            if (context.getParent() instanceof ThemeSource) {
                themeSource = new DelegatingThemeSource();
                themeSource.setParentThemeSource((ThemeSource) context.getParent());
            }
            else {
                themeSource = new ResourceBundleThemeSource();
            }
            if (logger.isDebugEnabled()) {
                logger.debug("Unable to locate ThemeSource with name '" + THEME_SOURCE_BEAN_NAME +
                        "': using default [" + themeSource + "]");
            }
            return themeSource;
        }
    }

⑪registerListeners()：将各种监听器放入到对应的容器中

    protected void registerListeners() {
        // Register statically specified listeners first.
        for (ApplicationListener<?> listener : getApplicationListeners()) {
            getApplicationEventMulticaster().addApplicationListener(listener);
        }

        // Do not initialize FactoryBeans here: We need to leave all regular beans
        // uninitialized to let post-processors apply to them!
        String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
        for (String listenerBeanName : listenerBeanNames) {
            getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
        }

        // Publish early application events now that we finally have a multicaster...
        Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
        this.earlyApplicationEvents = null;
        if (earlyEventsToProcess != null) {
            for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
                getApplicationEventMulticaster().multicastEvent(earlyEvent);
            }
        }
    }

⑫finishBeanFactoryInitialization(beanFactory)：bean实例化，单独开一章研究

⑬finishRefresh();refresh结束，推送相关事件

    protected void finishRefresh() {
        //清空资源缓存
        clearResourceCaches();

        // 初始化容器的生命周期处理器
        initLifecycleProcessor();

        // 将refresh推送给生命周期处理器
        getLifecycleProcessor().onRefresh();

        // 监听器执行，ApplicationListener.onApplicationEvent()
        publishEvent(new ContextRefreshedEvent(this));

        // 注册容器到LiveBeansView中，由LiveBeansView监控容器？
        LiveBeansView.registerApplicationContext(this);
    }

⑭destroyBeans()：refresh失败时，删除已经创建的单例bean

⑮cancelRefresh(ex);refresh失败时，设置active标志=false

⑯resetCommonCaches();清空公共反射缓存

    protected void resetCommonCaches() {
        ReflectionUtils.clearCache();
        AnnotationUtils.clearCache();
        ResolvableType.clearCache();
        CachedIntrospectionResults.clearClassLoader(getClassLoader());
    }