Spring为Struts2依赖注入失败，导致nullpointerexception
Web.xml如下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>shop9</display-name>
  <context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>classpath:beans.xml</param-value>
  </context-param>
  <listener>
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <filter>
  <filter-name>struts2</filter-name>
  <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
  </filter>
  <filter-mapping>
  <filter-name>struts2</filter-name>
  <url-pattern>/*</url-pattern>
  </filter-mapping>
  
  <welcome-file-list>
  <welcome-file>index.html</welcome-file>
  <welcome-file>index.htm</welcome-file>
  <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>

Struts.xml如下：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "struts-2.1.dtd">
<struts>
<package name="producttype" extends="struts-default" namespace="/control/product/type">
<action name="list" class="com.itcast.action.product.ProductTypeAction">
<result name="success">/test.jsp</result>
</action>
</package>
</struts>

beans.xml如下：

<?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:context="http://www.springframework.org/schema/context"
  xmlns:aop="http://www.springframework.org/schema/aop"
  xmlns:tx="http://www.springframework.org/schema/tx"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
  http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
  http://www.springframework.org/schema/context
  http://www.springframework.org/schema/context/spring-context-2.5.xsd
  http://www.springframework.org/schema/aop 
  http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
  http://www.springframework.org/schema/tx 
  http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
   
  <context:component-scan base-package="com.itcast"/>
  <context:property-placeholder location="classpath:jdbc.properties"/>
   
  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"