spring练习

public interface UserMapper {

public User selectUserById(@Param("id")Long id);

public void deleteUserById(@Param("id")long id);

}

public interface UserService {
public User findUserById(Long id);

public void deleteUserById(long id);

}

@Controller
@RequestMapping(“user”)
public class UserController {

@Autowired
private UserService userService;

@RequestMapping("showuser")
public String showUser(@RequestParam("id")long id, Model model){
    User user = userService.findUserById(id);
    model.addAttribute("user",user);
    return "user";
}