cache:annotation-driven" 的前缀 "cache" 未绑定

问题：

Caused by: org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 29 in XML document from class path resource [applicationContext-ehcache.xml] is invalid; nested exception is org.xml.sax.SAXParseException; lineNumber: 29; columnNumber: 58;

元素 "cache:annotation-driven" 的前缀 "cache" 未绑定。

原因：

是由于没有导入cache的命名空间，因此我们导入以下命名空间就可以解决

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xmlns:cache="http://www.springframework.org/schema/cache"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/cache
        http://www.springframework.org/schema/cache/spring-cache-4.2.xsd">