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

class Jtt
{
    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 = Jtt::getInstance();
$res = $app->execute('api/get_goods_link', [
    'unionid' => '1937243904',
    'gid' => $param['gid'],
]);