mybatis plus 校验用户名是否重复

//判断登录名的唯一性
QueryWrapper<User> query = new QueryWrapper<>();
query.lambda().eq(User::getLoginName,user.getLoginName());
User one = userService.getOne(query);
if(one != null && one.getUserId() != user.getUserId()){
    return ResultUtils.error("用户名已经被占用！",500);
}

//判断登录名的唯一性
        QueryWrapper<User> query = new QueryWrapper<>();
        query.lambda().eq(User::getLoginName,user.getLoginName());
        User one = userService.getOne(query);
        if(one != null && one.getUserId() != user.getUserId()){
            return ResultUtils.error("用户名已经被占用！",500);
        }