我的css文件未加载

我疯了，为什么我的css文件没有被加载。我正在使用spring mvc 4+apache tomcat 8

我已经将相同的代码用于其他项目，并且可以正常工作。
这是我的项目结构

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">

  <display-name>AO</display-name>


    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>hibernate.xml</param-value>
    </context-param>


    <servlet>
        <servlet-name>mvc-dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>mvc-dispatcher-servlet.xml</param-value>
        </init-param> 
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>mvc-dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>



</web-app>

我的servlet上下文：

<context:component-scan base-package="controller"/>
<mvc:annotation-driven />

<mvc:resources mapping="/RESOURCES/**" location="/RESOURCES/" />  

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/pages/" />
    <property name="suffix" value=".jsp" />
</bean>

当他尝试加载时：

<link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/RESOURCES/css/welcome.css" > 

要么

<link rel="stylesheet" type="text/css" href="/RESOURCES/css/welcome.css">

要么

<link rel="stylesheet" type="text/css" href="/AO/RESOURCES/css/welcome.css">

我收到此错误：

GET http://localhost:8080/AO/RESOURCES/css/welcome.css 404 (Introuvable)