如何在PHP中通过Google Plus登录

Question

致命错误：找不到类“ Google_client”

<?php  
    require_once "Google/vendor/autoload.php";
    $client = new Google_client();
    $client->setAuthConfig("client_credentials.json");
    $client->addScope(Google_Service_Oauth2::PLUS_LOGIN);
    $client->setScopes(array('https://www.googleapis.com/auth/userinfo.email','https://www.googleapis.com/auth/userinfo.profile'));
    $client->setRedirectUri("http://www.georeachtech.com/garagenu/gmail.php");
?>