Spring MVC 上传文件 和 struts2 的过滤器冲突问题

如果我在 web.xml 里面设置

<filter>
<!--过滤器名字  -->
<filter-name>struts2</filter-name>
<!-- 过滤器支持的struts2类  -->
<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>

<filter-mapping>
<!--过滤器拦截名字  -->
<filter-name>struts2</filter-name>
<!--过滤器拦截文件路径名字 action  -->
<url-pattern>*</url-pattern>
</filter-mapping>


使用 Spring MVC 上传文件有会有问题，去掉这个 struts2 过滤器，上传文件就没有问题

设置过滤器， org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
这里出问题，请问如何解决？




过滤器错误：
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)


java.lang.NullPointerException
com.edu.controller.FileUploadController.fileUpload(FileUploadController.java:47)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:606)
org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:413)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)