@RequestMapping(value="login/authUser", method=RequestMethod.POST)
public String authUser(@RequestParam("login") String login,
                        @RequestParam("password") String password, ModelMap model){
(...)
if (password.equals(user.getPassword())){
            ModelMap modelMap = new ModelMap();
            modelMap.put("loggedUser", user.getName() + " " + user.getSurname());
            return "home";
        }
        else{
            model.put("info", "Bad data!");
            return "index";
        }