protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
	// Tell the internal bean factory to use the context's class loader etc.
	// 设置beanFactory的classLoader为当前context的classLoader
	beanFactory.setBeanClassLoader(getClassLoader());
	// 设置beanFactory的表达式语言处理器，spring3增加了表达式语言的支持，默认可以使用#{bean.xxx}的形式来调用相关属性值。
	beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
	// 添加属性编辑器，更准确应该是属性转换器，比如从String到Date类型的转化
	beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

	// Configure the bean factory with context callbacks.
	// 添加后置处理器
	beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
	// 忽略给定接口的自动装配功能，典型应用是通过XXAware接口进行注入时不需要自动初始化依赖属性
	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.
	// 设置几个自动装配规则，例如如果是BeanFactory则注入beanFactory
	// 如果是ResourceLoader，ApplicationEventPublisher，ApplicationContext注入当前对象
	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.
	beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

	// Detect a LoadTimeWeaver and prepare for weaving, if found.
	// 如果包含LoadTimeWeaver，增加对AspectJ支持
	if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
		// 添加后置处理器
		beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
		// Set a temporary ClassLoader for type matching.
		beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
	}

	// Register default environment beans.
	// 这里个属性都是系统属性，之前是单独存在的并没有注入到容器中，这里把系统属性注入到容器中
	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());
	}
}

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
	// getBeanFactoryPostProcessors: 获取的手动注册的BeanFactoryPostProcessor
	PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());

	// 如果同时发现了一个LoadTimeWeaver就做相应的织入准备
	// Detect a LoadTimeWeaver and prepare for weaving, if found in the meantime
	// (e.g. through an @Bean method registered by ConfigurationClassPostProcessor)
	if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
		beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
		beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
	}
}

public static void invokeBeanFactoryPostProcessors(
		ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {

	// Invoke BeanDefinitionRegistryPostProcessors first, if any.
	// 处理过的bean
	Set<String> processedBeans = new HashSet<>();

	// 对BeanDefinitionRegistry类型的处理
	if (beanFactory instanceof BeanDefinitionRegistry) {
		BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
		List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
		List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();

		// 硬编码注册的后处理器
		for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
			if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {	// 子接口
				BeanDefinitionRegistryPostProcessor registryProcessor =
						(BeanDefinitionRegistryPostProcessor) postProcessor;
				// 对于BeanDefinitionRegistryPostProcess类型，在BeanFactoryPostProcessor基础上还有自己定义的方法，需要先调用 
				// 通过AbstractApplicationContext中添加处理器方法addBeanFactoryPostProcessor进行添加
				registryProcessor.postProcessBeanDefinitionRegistry(registry);
				registryProcessors.add(registryProcessor);
			}
			else {
				// 记录常规BeanFactoryPostProcessor
				regularPostProcessors.add(postProcessor);
			}
		}

		// Do not initialize FactoryBeans here: We need to leave all regular beans
		// uninitialized to let the bean factory post-processors apply to them!
		// Separate between BeanDefinitionRegistryPostProcessors that implement
		// PriorityOrdered, Ordered, and the rest.
		// 当前待处理BeanDefinitionRegistryPostProcessor
		List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();

		// 配置注册的后处理器(BeanDefinitionRegistryPostProcessor)，PriorityOrdered、Ordered、其他
		// 处理方法都相同: 放入容器，排序，执行BeanDefinitionRegistryPostProcessor的生命周期方法postProcessBeanDefinitionRegistry
		// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
		String[] postProcessorNames =
				beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
		for (String ppName : postProcessorNames) {
			// PriorityOrdered实现类
			if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
				currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
				processedBeans.add(ppName);
			}
		}
		sortPostProcessors(currentRegistryProcessors, beanFactory);
		registryProcessors.addAll(currentRegistryProcessors);
		invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
		currentRegistryProcessors.clear();

		// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
		postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
		for (String ppName : postProcessorNames) {
			// Ordered实现类
			if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
				currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
				processedBeans.add(ppName);
			}
		}
		sortPostProcessors(currentRegistryProcessors, beanFactory);
		registryProcessors.addAll(currentRegistryProcessors);
		invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
		currentRegistryProcessors.clear();

		// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
		boolean reiterate = true;
		while (reiterate) {
			reiterate = false;
			postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
			for (String ppName : postProcessorNames) {
				if (!processedBeans.contains(ppName)) {
					currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
					processedBeans.add(ppName);
					reiterate = true;
				}
			}
			sortPostProcessors(currentRegistryProcessors, beanFactory);
			registryProcessors.addAll(currentRegistryProcessors);
			invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
			currentRegistryProcessors.clear();
		}

		// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
		// 3种类型处理完后，再执行BeanFactoryPostProcessor的生命周期方法postProcessBeanFactory
		invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
	}

	else {
		// Invoke factory processors registered with the context instance.\
		// 否则直接执行BeanFactoryPostProcessor的生命周期方法postProcessBeanFactory
		invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
	}

	// Do not initialize FactoryBeans here: We need to leave all regular beans
	// uninitialized to let the bean factory post-processors apply to them!
	// 再处理BeanFactoryPostProcessor，处理的方式同上面的BeanDefinitionRegistryPostProcessor一致
	// 先处理完PriorityOrdered，再处理Ordered，最后处理普通的
	// 要注意的是，因为BeanDefinitionRegistryPostProcessor也是BeanFactoryPostProcessor，并且他之前已经处理过了，所以这个过程就不会在处理了
	String[] postProcessorNames =
			beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);

	// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
	// Ordered, and the rest.
	List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
	List<String> orderedPostProcessorNames = new ArrayList<>();
	List<String> nonOrderedPostProcessorNames = new ArrayList<>();
	for (String ppName : postProcessorNames) {
		if (processedBeans.contains(ppName)) {
			// skip - already processed in first phase above
		}
		else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
			priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
		}
		else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
			orderedPostProcessorNames.add(ppName);
		}
		else {
			nonOrderedPostProcessorNames.add(ppName);
		}
	}

	// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
	sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
	invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);

	// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
	List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();
	for (String postProcessorName : orderedPostProcessorNames) {
		orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
	}
	sortPostProcessors(orderedPostProcessors, beanFactory);
	invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);

	// Finally, invoke all other BeanFactoryPostProcessors.
	List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
	for (String postProcessorName : nonOrderedPostProcessorNames) {
		nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
	}
	invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);

	// Clear cached merged bean definitions since the post-processors might have
	// modified the original metadata, e.g. replacing placeholders in values...
	beanFactory.clearMetadataCache();
}

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.
	int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
	beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

	// Separate between BeanPostProcessors that implement PriorityOrdered,
	// Ordered, and the rest.
	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.
	sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
	registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

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

	// Now, register all regular BeanPostProcessors.
	List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
	for (String ppName : nonOrderedPostProcessorNames) {
		// 这些BeanPostProcessor会在这个方法内被实例化(通过调用BeanFactory的getBean方法，如果没有找到实例化的类，就会去实例化)
		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.
	sortPostProcessors(internalPostProcessors, beanFactory);
	registerBeanPostProcessors(beanFactory, internalPostProcessors);

	// Re-register post-processor for detecting inner beans as ApplicationListeners,
	// moving it to the end of the processor chain (for picking up proxies etc).
	beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}

protected void finishRefresh() {
	// Clear context-level resource caches (such as ASM metadata from scanning).
	// 清空resourceCaches缓存： resourceCaches.clear()
	clearResourceCaches();

	// -2:Initialize lifecycle processor for this context.
	initLifecycleProcessor();

	// -3:Propagate refresh to lifecycle processor first.
	getLifecycleProcessor().onRefresh();

	// -5:Publish the final event.
	publishEvent(new ContextRefreshedEvent(this));

	// -6:Participate in LiveBeansView MBean, if active.
	LiveBeansView.registerApplicationContext(this);
}

protected void initLifecycleProcessor() {
	ConfigurableListableBeanFactory beanFactory = getBeanFactory();
	if (beanFactory.containsLocalBean(LIFECYCLE_PROCESSOR_BEAN_NAME)) {
		this.lifecycleProcessor =
				beanFactory.getBean(LIFECYCLE_PROCESSOR_BEAN_NAME, LifecycleProcessor.class);
		if (logger.isDebugEnabled()) {
			logger.debug("Using LifecycleProcessor [" + this.lifecycleProcessor + "]");
		}
	}
	else {
		// 上下文没有找到则创建DefaultLifecycleProcessor
		DefaultLifecycleProcessor defaultProcessor = new DefaultLifecycleProcessor();
		defaultProcessor.setBeanFactory(beanFactory);
		this.lifecycleProcessor = defaultProcessor;
		// 注册，放入factory单例cache，放入manualSingletonNames
		beanFactory.registerSingleton(LIFECYCLE_PROCESSOR_BEAN_NAME, this.lifecycleProcessor);
		if (logger.isDebugEnabled()) {
			logger.debug("Unable to locate LifecycleProcessor with name '" +
					LIFECYCLE_PROCESSOR_BEAN_NAME +
					"': using default [" + this.lifecycleProcessor + "]");
		}
	}
}

public void onRefresh() {
	startBeans(true);
	this.running = true;
}

private void startBeans(boolean autoStartupOnly) {
	Map<String, Lifecycle> lifecycleBeans = getLifecycleBeans();
	Map<Integer, LifecycleGroup> phases = new HashMap<>();
	lifecycleBeans.forEach((beanName, bean) -> {
		if (!autoStartupOnly || (bean instanceof SmartLifecycle && ((SmartLifecycle) bean).isAutoStartup())) {
			int phase = getPhase(bean);
			LifecycleGroup group = phases.get(phase);
			if (group == null) {
				group = new LifecycleGroup(phase, this.timeoutPerShutdownPhase, lifecycleBeans, autoStartupOnly);
				phases.put(phase, group);
			}
			group.add(beanName, bean);
		}
	});
	if (!phases.isEmpty()) {
		List<Integer> keys = new ArrayList<>(phases.keySet());
		Collections.sort(keys);
		for (Integer key : keys) {
			phases.get(key).start();
		}
	}
}

public void start() {
	if (this.members.isEmpty()) {
		return;
	}
	if (logger.isInfoEnabled()) {
		logger.info("Starting beans in phase " + this.phase);
	}
	Collections.sort(this.members);
	for (LifecycleGroupMember member : this.members) {
		if (this.lifecycleBeans.containsKey(member.name)) {
			doStart(this.lifecycleBeans, member.name, this.autoStartupOnly);
		}
	}
}

private void doStart(Map<String, ? extends Lifecycle> lifecycleBeans, String beanName, boolean autoStartupOnly) {
	Lifecycle bean = lifecycleBeans.remove(beanName);
	if (bean != null && bean != this) {
		String[] dependenciesForBean = getBeanFactory().getDependenciesForBean(beanName);
		for (String dependency : dependenciesForBean) {
			doStart(lifecycleBeans, dependency, autoStartupOnly);
		}
		if (!bean.isRunning() &&
				(!autoStartupOnly || !(bean instanceof SmartLifecycle) || ((SmartLifecycle) bean).isAutoStartup())) {
			if (logger.isDebugEnabled()) {
				logger.debug("Starting bean '" + beanName + "' of type [" + bean.getClass() + "]");
			}
			try {
				// 调用SmartLifecycle接口实现类的start方法
				bean.start();
			}
			catch (Throwable ex) {
				throw new ApplicationContextException("Failed to start bean '" + beanName + "'", ex);
			}
			if (logger.isDebugEnabled()) {
				logger.debug("Successfully started bean '" + beanName + "'");
			}
		}
	}
}

protected void publishEvent(Object event, @Nullable ResolvableType eventType) {
	Assert.notNull(event, "Event must not be null");
	if (logger.isTraceEnabled()) {
		logger.trace("Publishing event in " + getDisplayName() + ": " + event);
	}

	// Decorate event as an ApplicationEvent if necessary
	// 创建的ContextRefreshedEvent是继承自ApplicationEvent
	ApplicationEvent applicationEvent;
	if (event instanceof ApplicationEvent) {
		applicationEvent = (ApplicationEvent) event;
	}
	else {
		applicationEvent = new PayloadApplicationEvent<>(this, event);
		if (eventType == null) {
			eventType = ((PayloadApplicationEvent) applicationEvent).getResolvableType();
		}
	}

	// Multicast right now if possible - or lazily once the multicaster is initialized
	if (this.earlyApplicationEvents != null) {
		this.earlyApplicationEvents.add(applicationEvent);
	}
	else {
		// 使用上注册的事件广播器ApplicationEventMulticaster(SimpleApplicationEventMulticaster)广播ContextRefreshedEvent事件
		getApplicationEventMulticaster().multicastEvent(applicationEvent, eventType);
	}

	// Publish event via parent context as well...
	if (this.parent != null) {
		if (this.parent instanceof AbstractApplicationContext) {
			((AbstractApplicationContext) this.parent).publishEvent(event, eventType);
		}
		else {
			this.parent.publishEvent(event);
		}
	}
}

static void registerApplicationContext(ConfigurableApplicationContext applicationContext) {
	String mbeanDomain = applicationContext.getEnvironment().getProperty(MBEAN_DOMAIN_PROPERTY_NAME);
	// 看是否配置了spring.liveBeansView.mbeanDomain属性
	if (mbeanDomain != null) {
		synchronized (applicationContexts) {
			if (applicationContexts.isEmpty()) {
				try {
					MBeanServer server = ManagementFactory.getPlatformMBeanServer();
					applicationName = applicationContext.getApplicationName();
					server.registerMBean(new LiveBeansView(),
							new ObjectName(mbeanDomain, MBEAN_APPLICATION_KEY, applicationName));
				}
				catch (Throwable ex) {
					throw new ApplicationContextException("Failed to register LiveBeansView MBean", ex);
				}
			}
			applicationContexts.add(applicationContext);
		}
	}
}

// Reset Spring's common reflection metadata caches
protected void resetCommonCaches() {
	ReflectionUtils.clearCache();
	AnnotationUtils.clearCache();
	ResolvableType.clearCache();
	CachedIntrospectionResults.clearClassLoader(getClassLoader());
}