Symfony实体管理员电话

Question

I want to know if there's any difference to call Entity manager on a Symfony3 Controller:

$this->getDoctrine()->getManager()

And:

$this->get('doctrine.orm.entity_manager');

Performance? More Correct?

Thanks so much in advance, Carl Dev

Answer 1

I think both are the same a performance level, but are those correct? i think no, Symfony have a beautiful feature call "dependency injection" ( https://symfony.com/doc/current/components/dependency_injection.html ), you have never ever to call a service directly, why? because is hard to test, for example:

    public function test()
{
     $manager = $this->getDoctrine()->getManager();
     $manager->persist(new MyClass());
     $manager->flush();
}

If you want to test this call that method, you have to have a Manager point to somewhere, so your test depends on infrastructure.

Now, imagine this:

public function test(EntityManager $manager)
    {
         $manager->persist(new MyClass());
         $manager->flush();
    }

You can mock that entity manager or implement a onMemoryEntityManager removing that dependency.

There are so many theory behind this i suggest to read this:

https://en.wikipedia.org/wiki/Dependency_injection and https://symfony.com/doc/3.3/components/dependency_injection.html

Answer 2

The first method is only available when you extending the base controller so it's possibile to use into a controller usually. It's the shortcut of the second method.

The second method is useful when you need the entity manager as a service inside your class for example and is the correct way of getting the doctrine entity manager.