ssh action中service无法注入，报空指针问题

action为：public class RegistAction {private IRegistService iregistService;private SshUser sshUser;public String registUser(){System.out.println("=========>"+iregistService);iregistService.registUser(sshUser);return "success";}struts配置为：<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts>     <!--  <include file="struts-default.xml"></include> --> <!-- 这句话是将struts交给spring管理 --><constant name="struts.objectFactory" value="spring"></constant><package name="sshTestPackage" extends="struts-default" namespace="/">    <action name="registAction" class="registAction" method="registUser">        <result name="success">/hello.html</result>    </action></package> </struts>    action里面的service无法注入的原因，就是struts未交付spring托管，<constant name="struts.objectFactory" value="spring"></constant>的作用就是将struts交付spring托管，同时，action的class必须改为spring配置文件中action的id名