在Controller Symfony2中调用非对象的成员函数get（）

Question

I'm new in OroCRM and Symfony2,in method update of my DefaultController I create an instance of OroCRM\Bundle\MagentoBundle\Controller\CustomerController and call its method

    $customerController = new CustomerController();
    $customerController->update($extendCustomer);

$extendCustomer is an inheritace of OroCRM\Bundle\MagentoBundle\Entity\Customer

    class ExtendCustomer extends Customer

But when I call method update of CustomerController it throws this error:

Fatal error: Call to a member function get() on a non-object in /var/www/html/crm-application/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Controller/Controller.php on line 350

I have worked on it for 2 days with everything i can search on google, but it still doesn't work. I understand that there are something with services, which i don't understand much. Please give me some advices. Thanks a lot.