Freemarker中通过request获得contextPath

<!-- config Freemarker View Resolver-->
       <bean id="viewResolver"  
         class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
            <property name="viewClass" value="org.springframework.web.servlet.view.freemarker.FreeMarkerView"/>  
         <property name="contentType" value="text/html;charset=utf-8"/>
         <property name="cache" value="true"/>
         <property name="suffix" value=".ftl"/>  
         <property name="order" value="0"/>  
         <property name="requestContextAttribute" value="request"/>
       </bean> 

　 <#assign ctx=request.getContextPath()>