1.修改UserService
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, UserDO> implements UserService {public UserRespDTO getUserByUsername(String username) {LambdaQueryWrapper<UserDO> queryWrapper = Wrappers.lambdaQuery(UserDO.class).eq(UserDO::getUsername,username);UserDO userDO = baseMapper.selectOne(queryWrapper);if (userDO != null) {UserRespDTO result = new UserRespDTO();BeanUtils.copyProperties(userDO, result);return result;} else {// UserDO是null，无法找到用户return null;}}
}2.完善UserContorller的为空报错
@RestController
@RequiredArgsConstructor
public class UserController {private final UserService userService;
/**
*根据用户名查询用户信息
*/@GetMapping("/api/shortlink/v1/user/{username}")public Result<UserRespDTO> getUserByUsername(@PathVariable("username") String username){UserRespDTO result = userService.getUserByUsername(username);if(result==null){return new Result<UserRespDTO>().setCode("-1").setMessage("用户查询为空");}else {return new Result<UserRespDTO>().setCode("0").setData(result);}}
}3.注意UserController中返回值的变化
String->UserRespDTO->Result<UserRespDTO>
