namespace app\common\factory;
use mengsen\jd\TopClient;

class Jd
{
    private static $obj = null;
    public static function getInstance()
    {
        if (self::$obj == null) {
            $conf = config('jd.union');
            $app = new TopClient($conf['appkey'], $conf['secretKey']);
            self::$obj = $app;
        }
        return self::$obj;
    }
}

DEMO

$app = Jindong::getInstance();
$res = $app->execute('jd.union.open.promotion.common.get', [
    'promotionCodeReq' => [
        'siteId' => '1937243904',
        'materialId' => $param['material_id'],
        // 'ext1' => 'h5'
    ],
]);