public static Result update() {
   Map<String, String> map = DynamicForm.form().bindFromRequest().data();
   NewsCategory nc = new NewsCategory();
   nc.category_code = map.get("category_code");
   nc.category_title = map.get("category_title");
   String is_channel = map.get("is_channel");
   nc.parent_category_code = map.get("parent_category_code");
   if (is_channel != null && is_channel.equals("on")) {
     nc.is_channel = true;
   }
   NewsCategory.modifyNewsCategory(nc);
   return redirect("/admin/news/category");
 }