类似下列问题：BeanCreationException很可能是applicationContext.xml配置错误或相关的类文件，hbm.xml文件错误，要仔细查询问题。
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry destroySingletons
信息: Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@1e7d8b1: defining beans [c,dao,sf,ds]; root of factory hierarchy
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dao' defined in class path resource [applicationContext.xml]