//1.在Global.asax文件中
        public static void RegisterGlobalFilters(GlobalFilterCollection filters) {
            filters.Add(new ExceptionFilterAttribute());  //自己定义的过滤器
        }
      /// <summary>
      /// 2.自己定义的过滤器 处理异常跳转错误页
      /// 捕获异常 跳转到错误页
      /// </summary>
    public class ExceptionFilterAttribute : HandleErrorAttribute {
        public override void OnException(ExceptionContext filterContext) {
            base.OnException(filterContext);
            string excepitonInfo = filterContext.Exception.ToString();
            LogHelper.OutputLog(excepitonInfo);
            filterContext.HttpContext.Response.Redirect("/WebPages/Error.htm");
        }
    }