UserListController

@Controller
public class UserListController {
    @Autowired
    private UserService userService;
    
    // URL「/user」, HTTPメソッドGETとマッピング
    @RequestMapping(value = "/user", method = RequestMethod.GET)
    public String showAllPerson(
        @RequestParam("userId") int userId, Model model) {
            
            User user = userService.fingbyId(userId);
            // Viewに渡すオブジェクトを設定
            model.addAttribute("user", user);
            // View名をreturn
            return "user/detail";
            
        }
}