java.lang.IllegalArgumentException: Attribute value must not be null错误

错误原因是我在session中放入的空值导致java.lang.IllegalArgumentException: Attribute value must not be null ,设置值之前判断一下空值

//如下代码
public String about(Model model) {
BlogUser user = blogUserService.findAdminUser();
//user是null则会造成这个错误
model.addAttribute("user", user);
return "about";
}