Spring源码：prepareBeanFactory(beanFactory);方法

// Prepare the bean factory for use in this context.

//添加一些 Spring 本身需要的一些工具类

prepareBeanFactory(beanFactory);

/**
* Configure the factory's standard context characteristics,
* such as the context's ClassLoader and post-processors.
* @param beanFactory the BeanFactory to configure
*/
//配置工厂标准上下文的特征，例如上下文的类加载器和前置处理器
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
   // Tell the internal bean factory to use the context's class loader etc.
   //bean工厂设置类加载器
   beanFactory.setBeanClassLoader(getClassLoader());


   //创建一个新的StandardBeanExpressionResolver实例，此实例拥有类加载器的引用
   //在bean定义的值中，此实例为表达式的使用指定解决策略，上下文通常会设置标准的表达式策略支持"#{...}"EL表达式，例如数据库信息的引用
   beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));


   //创建一个新的ResourceEditorRegistrar自定义属性编辑器实例，此实例拥有类加载器和Environment的引用
   //将这个ResourceEditorRegistrar实例添加到bean工厂的propertyEditorRegistrars属性中
   //propertyEditorRegistrars是LinkedHashSet类型，定制自定义策略，来扩展propertyEditor，适用于所有bean的创建过程
   //案例：一个重要的使用就是将xml中bean中的属性值注入到class对象中
   beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));


   // Configure the bean factory with context callbacks.
   //通过上下文回调配置bean工厂
   //BeanPostProcessor（SF中特别重要的一个接口）允许我们自定义修改bean的属性，可以创建此接口的实现类,修改bean信息
   //在bean工厂添加BeanPostProcessor处理器，用于创建bean（creatBean），BeanPostProcessor是CopyOnWriteArrayList类型，线程安全
   beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
   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接口未在普通工厂中注册为可解析类型。
   //MessageSource注册为bean（并发现用于自动装配）。
   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.
   //注册早期的后处理器以将内部bean检测为ApplicationListeners。
   beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));


   // Detect a LoadTimeWeaver and prepare for weaving, if found.
   //如果发现LoadTimeWeaver，请准备编织。
   if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
      beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
      // Set a temporary ClassLoader for type matching.
      //为类型匹配设置一个暂时的类加载器
      beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
   }


   // Register default environment beans.
   //注册默认的环境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());
   }
}