was 6 升级到 8.5, struts 项目无法部署, 求解答,谢谢

错误页面异常:SRVE0260E: 服务器无法使用对应用程序指定的错误页来处理如下所示的原始异常。
原始异常:错误消息: javax.servlet.ServletException: Filter [struts2]: could not be initialized
错误代码: 500
目标 servlet: com.ibm.ws.webcontainer.extension.DefaultExtensionProcessor
错误堆栈:
Class: com.opensymphony.xwork2.spring.SpringObjectFactory
     File: SpringObjectFactory.java
     Method: getClassInstance
     Line: 220 - com/opensymphony/xwork2/spring/SpringObjectFactory.java:220:-1
     at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:428)
     at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
     at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51)
     at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.init(FilterInstanceWrapper.java:145)

  Caused by: java.lang.NullPointerException
     at com.opensymphony.xwork2.spring.SpringObjectFactory.getClassInstance(SpringObjectFactory.java:220)
     at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.verifyResultType(XmlConfigurationProvider.java:530)
     at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addResultTypes(XmlConfigurationProvider.java:501)
     at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:457)
     at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:275)
     at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:111)
     at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:204)
     at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
     at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:371)
     at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:415)
     ... 28 more