Struts 2.0 + Hibernate + Spring 3.0整合的一个疑惑

整合ss的时候,在struts2-spring-plugin-2.1.6.jar这个包里面,有一个配置文件,内容为<struts>
    <bean type="com.opensymphony.xwork2.ObjectFactory" name="spring" class="org.apache.struts2.spring.StrutsSpringObjectFactory" />
    
    <!--  Make the Spring object factory the automatic default -->
    <constant name="struts.objectFactory" value="spring" />    <package name="spring-default">
        <interceptors>
            <interceptor name="autowiring" class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/>
            <interceptor name="sessionAutowiring" class="org.apache.struts2.spring.interceptor.SessionContextAutowiringInterceptor"/>
        </interceptors>
    </package>    
</struts>这里修改了 struts.objectFactory  的工厂,名字为spring,类就是前面定义的org.apache.struts2.spring.StrutsSpringObjectFactory