表单数据未保存在会话中

Question

用户输入数据时以及注册之前如果他单击链接，     单击返回链接，用户输入的表单数据将丢失。

@SessionAttributes("user")
@Controller
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping(value="/",method=RequestMethod.GET)
    public String registerPage(@ModelAttribute("user") User user, HttpServletRequest request, Model model){
        System.out.println(request.getSession());
        return "register";
    }

    @RequestMapping(value="/terms",method=RequestMethod.GET)
    public String terms(@ModelAttribute("user") User user, HttpServletRequest request, Model model){
        System.out.println(request.getSession());
        return "terms";
    }


}