根据不同类型，实例化不同的类

// 增加一个类型，在这里增加一对键值对
$supportedClass=[
	"image" => "\App\Lib\Upload\Image",
	"video" => "\App\Lib\Upload\Video",
];

// $type:上传文件的类型
// $request:上传文件的参数
$uploadObj = $classObj->initClass($type, $supportedClass, [$request, $type]);
$file = $uploadObj->upload();

public function initClass($type, $supportedClass = [], $params = [])
	{
		//拼接要实例化的类的路径，如：\App\Lib\Upload\Image
		$className = $supportedClass[$type];

		return $needInstance ? (new \ReflectionClass($className))->newInstanceArgs($params) : $className;
	}