在安装DomPDF包之后，我已经做了composer require barryvdh/laravel-dompdf和php artisan vendor:publish --provider="Barryvdh\DomPDF\ServiceProvider".
我拨打了use PDF；
$pdf = PDF::loadHTML($html);
// Set the paper size (optional)
$pdf->setPaper('A4', 'portrait');
// Download the PDF with a specific file name
return $pdf->stream('sample.pdf')
All That to Receive，还会将包裹别名为'PDF' => Barryvdh\DomPDF\Facade::class
未定义类型‘PDF’
可能出了什么问题，谢谢.