类型转换出错 400 请求报错 

类型转换出错 将DefaultServletHttpRequestHandler 转换为HandlerMethod类型

org.springframework.web.servlet.resource.DefaultServletHttpRequestHandler cannot be cast to org.springframework.web.method.HandlerMethod
如何将DefaultServletHttpRequestHandler 转换为HandlerMethod类型
在
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    String businessName = resolve(urlPathHelper.getServletPath(request));         request.setAttribute(TENANT_BUSINESS_NAME_KEY, businessName);         // restrict the access         HandlerMethod  method = (HandlerMethod) handler;         TenantResource tenantResource = method.getMethodAnnotation(TenantResource.class);         RootResource rootResource = method.getMethodAnnotation(RootResource.class);         boolean isRootResource = false;         // get annotation from class when no annotation is specified         if (tenantResource == null && rootResource == null) {             tenantResource = AnnotationUtils.findAnnotation(method.getBeanType(), TenantResource.class);             rootResource = AnnotationUtils.findAnnotation(method.getBeanType(), RootResource.class);         }

        // still with no annotation, set default         if (tenantResource == null && rootResource == null) {             isRootResource = true;         }

        // tenant resource         if (tenantResource != null && StringUtils.isEmpty(businessName)) {             throw new NoHandlerFoundException(request.getMethod(), request.getRequestURI(), null);         }

        // root resource         if ((rootResource != null || isRootResource) && !StringUtils.isEmpty(businessName)) {             throw new NoHandlerFoundException(request.getMethod(), request.getRequestURI(), null);         }
        return super.preHandle(request, response, handler);     } 加红的那句出错了，求大神帮助