Spring:Looks like the Spring listener was not configured for your web app!

1.Spring整合Struts2：配置文件问题
在Spring整合Struts2时出现的一个问题，其实Log的前几句已经告诉我们错误的原因了，因为忘记在web.xml配置文件中没有配置Spring Listener，当我们配置了ConextLoaderListener后，该监听器会在创建时自动查找WEB-INF/路径下applicationContext.xml文件，所以除了配置该ConextLoaderListener，我们还需要将applicationContext.xml放在WEB-INF下

异常如下:

Looks like the Spring listener was not configured for your web app! 
Nothing will work until WebApplicationContextUtils returns a valid ApplicationContext.

<listener>
        <listener-class>
               org.springframework.web.context.ContextLoaderListener
         listener-class>
listener>

com.opensymphony.xwork2.util.logging.commons.CommonsLogger error
严重: Dispatcher initialization failed

java.lang.NullPointerException at 
com.opensymphony.xwork2.spring.SpringObjectFactory.
getClassInstance(SpringObjectFactory.java:209) at 
com.opensymphony.xwork2.config.providers.
XmlConfigurationProvider.verifyResultType(XmlConfigurationProvider.java:519)