columnNumber:54; 元素 "context:component-scan" 的前缀 "context" 未绑定

<!-- 自动扫描与装配，包含子包 -->  
<context:component-scan base-package="cn.mdl.*"></context:component-scan>  

配置完之后，通过junit4测试spring的配置，提示columnNumber:54; 元素 “context:component-scan” 的前缀 “context” 未绑定是少了context的命名空间的问题：

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:rabbit="http://www.springframework.org/schema/rabbit"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
    http://www.springframework.org/schema/beans  
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/rabbit 
    http://www.springframework.org/schema/rabbit/spring-rabbit-1.6.xsd
    http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-3.1.xsd
    http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.1.xsd">

添加：
第4行：

xmlns:context="http://www.springframework.org/schema/context"

第12行：

http://www.springframework.org/schema/context 

第13行：

http://www.springframework.org/schema/context/spring-context-3.1.xsd