API Youtube - >致命错误：找不到类'Google_Service'

I'm getting an error in php, when I try to include the google api php client as follow:

require_once '\google-api-php-client-master\src\Google\Client.php';
require_once '\google-api-php-client-master\src\Google\Service\youtube.php';

Likewise, I try to include autoload.php file as follow:

require_once '\google-api-php-client-master\src\Google\autoload.php';

But a different error appears:

Fatal error: Uncaught exception 'Exception' with message 'This library must be installed via composer or by downloading the full package. See the instructions at https://github.com/google/google-api-php-client#installation

The codes that I am trying to test appear in the following link:

Https://developers.google.com/youtube/v3/code_samples/php

PD: sorry for my bad english

The error is more specific to PHP rather than this specific package.

You cannot use a PHP package just by downloading it. You need to install it and you may use any other package manager instead of composer as you wish.

You need to composer install the package google/apiclient.

In short, the file composer.json should include the following code snippet:

"require": {
    "google/apiclient": "2.0.*",
    "php": ">= 5.6.1"
 }

Once you ensure that you have the above snippet, run the following command:

composer install

After this, the error should not occur.

Hope this helps.

If the full package didn't work, try to use the composer like the suggestion in your error. You can find in this tutorial and this SO question on how to use composer.