您使用的导入错误.要使用所需的PDF(可能是laravel-dompdf)，请使用:

You are using the wrong import. To use the PDF you want (probably laravel-dompdf) use:

use Barryvdh\DomPDF\Facade as PDF;

如果将'PDF' => Barryvdh\DomPDF\Facade::class,放在config/app.php中，则还可以使用:

If you put 'PDF' => Barryvdh\DomPDF\Facade::class, in your config/app.php you could also use:

use \PDF;

或

\PDF::loadView('customer.customer');