（8）controller，service程序填空，改错

1. 填空：

Controller:

@RestController
@RequestMapping("/users")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User getUserById(@PathVariable Long id) {
        return userService.getUserById(id);
    }

    @PostMapping("/")
    public User createUser(@RequestBody User user) {
        return userService.createUser(user);
    }
}

Service:

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public User getUserById(Long id) {
        return userRepository.findById(id).orElse(null);
    }

    @Override
    public User createUser(User user) {
        return userRepository.save(user);
    }
}

2. 改错：

Controller:

@RestController
@RequestMapping("/users")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User getUserById(@PathVariable Long id) {
        return userService.getUserById(id);
    }

    @PostMapping("/")
    public User createUser(@RequestBody User user) {
        return userService.createUser(user);
    }
}

Service:

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public User getUserById(Long id) {
        return userRepository.findById(id).orElse(null);
    }

    @Override
    public User createUser(User user) {
        return userRepository.save(user);
    }
}

以上代码没有错误。