Fatal error: Uncaught Error: Class 'Symfony\Component\Validator\Mapping\Loader\FileLoader' not found in D:\workspaces\liZiPingBack\vendor\symfony\validator\Mapping\Loader\XmlFileLoader.php:23 Stack trace: #0 {main} thrown in D:\workspaces\liZiPingBack\vendor\symfony\validator\Mapping\Loader\XmlFileLoader.php on line 23