求问 strust与spring对象依赖注入问题

  采用spring set方式注入对象，但是对象一直提示为空，空指针异常！ web.xml   <?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <!-- struts过滤器 -->
  <filter>
    <filter-name>struts2</filter-name>
    <filter-class>
    org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
    </filter-class>
  </filter>
  <filter-mapping>
    <filter-name>struts2</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  
    <!-- spring  --> 
    <context-param>  
        <param-name>webAppRootKey</param-name>  
        <param-value>fjtelecomOA</param-value>  
    </context-param>  
    <context-param>  
        <param-name>contextConfigLocation</param-name>  
        <param-value>/WEB-INF/applicationContext.xml</param-value>  
    </context-param>  
  
    <listener>  
        <listener-class>  
            org.springframework.web.context.ContextLoaderListener  
        </listener-class>  
    </listener>  
  
  <!-- 文件上传辅助 -->
  <filter>
     <filter-name>struts-cleanup</filter-name>
     <filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class>
  </filter>
  <filter-mapping>
     <filter-name>struts-cleanup</filter-name>
     <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>
application.xml:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <bean id="tbFileAction"  class="com.action.UploadFileAction"  scope="prototype"> 
<property name="itfs" ref="tbFileService"></property>
    </bean>
<bean id="tbFileService" class="com.service.impl.TbFileServiceImpl">
</bean>
 
</beans>
action 也就是一个service接口对象以及set和get方法，再加上一个操作方法！
   private IFileService itfs;
  set get 方法
     public void testSpring(){
itfs.test();
}
在 itfs.test(）方法时报异常！  求解springstruts接口对象依赖注入