问题：

Configuration problem: Cannot locate BeanDefinitionDecorator for element [component-scan]
Offending resource: class path resource [applicationContext.xml]

错误配置：

配置组件扫描的语句位置放错地方了

<context:component-scan base-package="itheima"></context:component-scan>

将上面这句话放在配置数据源bean语句的外面即可