java 后台代码如何对数据进行封装

@RequestMapping('/loginAction.do') public String loginAction(String username,String password,HttpServletRequest request){  User user = null;  try {   user = userService.login(username.trim(), password.trim());  } catch (NameorPwdException e) {   // TODO Auto-generated catch block   e.printStackTrace();   } catch (NameorPwdEmptyException e) {   // TODO Auto-generated catch block   e.printStackTrace();   }

HttpSession session = (HttpSession) request.getSession();  session.setAttribute('storePhone', user.getUserName());  session.setAttribute('user', user);  session.setAttribute('code', '');  return 'redirect:sell.do'; }

@RequestMapping('/sell.do') public String sell(Model model,String phone,HttpServletRequest request){  HttpSession session = request.getSession();  String storePhone = (String) session.getAttribute('storePhone');  if(session.getAttribute('user')==null || ''.equals(session.getAttribute('user'))){   return 'redirect:/login/login.do';  }

public User  login(String name,String password) throws NameorPwdException, NameorPwdEmptyException{  if(name==null||''.equals(name.trim())||''.equals(password.trim())){   throw new NameorPwdEmptyException('用户名或密码不能为空');  }    User user = userDao.findByName(name);  if(user==null){   throw new NameorPwdException('用户名不存在');  }

if(user.getPassword().equalsIgnoreCase(password)){      return user;  }  System.out.println(name+'++'+password);  throw new NameorPwdException('密码错误'); }

public List findAllSeed(){  List seeds = seedDao.findAll();  return seeds; }

对登录异常统一处理封装；将数据封装实体对象，或者map集合传递到前端