主要作用：protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {// Tell the internal bean factory to use the context's class loader etc.//初始化类加载器 beanFactory.setBeanClassLoader(getClassLoader());//初始化SPEL解析器，也就是EL表达式的解析器beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));// 设置属性注册解析器PropertyEditor 这个主要是对bean的属性等设置管理的一个工具beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));// Configure the bean factory with context callbacks.//增加一个处理Aware相关接口的Bean处理器 并设置相关忽略的接口。beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));//具体应用在Bean初始化之前，属性填充过程中，进行属性的过滤。对于实现这些接口的，不做处理，由ApplicationContextAwareProcess处理。 具体详见 Spring创建Bean的过程分析 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.// 此处registerResolvableDependency()方法注意：它会把他们加入到DefaultListableBeanFactory的resolvableDependencies字段里面缓存这，供后面处理依赖注入的时候随时引用。 // 这也是为什么我们可以通过依赖注入的方式，直接注入这几个对象比如ApplicationContext可以直接依赖注入// 但是需要注意的是：这些Bean，IOC容器里其实是没有的。beanFactory.getBeanDefinitionNames()和beanFactory.getSingletonNames()都是找不到他们的，所以特别需要理解这一点。//只要获取到容器就可以获取到这些东西。 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.//加入一个监听器相关的监听器，主要作用是，将监听器的Bean加入到  详见 Bean相关的处理器(二)、ApplicationListenerDetector 介绍beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));// Detect a LoadTimeWeaver and prepare for weaving, if found.//检查容器中是否包含名称为loadTimeWeaver的bean  具体详见：代码的织入方式之loadTimeWeaver详解// AspectJ采用编译期织入、类加载期织入两种方式进行切面的织入if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {        // 在BEAN初始化之前检查BEAN是否实现了LoadTimeWeaverAware接口，// 如果是，则进行加载时织入，即静态代理。beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));// Set a temporary ClassLoader for type matching.beanFactory.setTempClassLoader(new                      ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));}//将默认的环境Bean注入到容器中，environment、systemProperties、SystemEnvironment// Register default environment beans.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());}
}