Symfony 2 EntityManager injection in service

问题:

I've created my own service and I need to inject doctrine EntityManager, but I don't see that __construct() is called on my service, and injection doesn't work.

Here is the code and configs:

<?php

namespace Test\CommonBundle\Services;
use Doctrine\ORM\EntityManager;

class UserService {

    /**
     *
     * @var EntityManager 
     */
    protected $em;

    public function __constructor(EntityManager $entityManager)
    {
        var_dump($entityManager);
        exit(); // I've never saw it happen, looks like constructor never called
        $this->em = $entityManager;
    }

    public function getUser($userId){
       var_dump($this->em ); // outputs null  
    }

}

Here is services.yml in my bundle

services:
  test.common.userservice:
    class:  Test\CommonBundle\Services\UserService
    arguments: 
        entityManager: "@doctrine.orm.entity_manager"

I've imported that .yml in config.yml in my app like that

imports:
    # a few lines skipped, not relevant here, i think
    - { resource: "@TestCommonBundle/Resources/config/services.yml" }

And when I call service in controller

    $userservice = $this->get('test.common.userservice');
    $userservice->getUser(123);

I get an object (not null), but $this->em in UserService is null, and as I already mentioned, constructor on UserService has never been called

One more thing, Controller and UserService are in different bundles (I really need that to keep project organized), but still: everyting else works fine, I can even call

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

in same controller that I use to get UserService and get valid (not null) EntityManager object.

Look like that I'm missing piece of configuration or some link between UserService and Doctrine config.

回答1:

Your class's constructor method should be called __construct(), not __constructor():

public function __construct(EntityManager $entityManager)
{
    $this->em = $entityManager;
}

回答2:

For modern reference, in Symfony 2.4+, you cannot name the arguments for the Constructor Injection method anymore. According to the documentation You would pass in:

services:
    test.common.userservice:
        class:  Test\CommonBundle\Services\UserService
        arguments: [ "@doctrine.orm.entity_manager" ]

And then they would be available in the order they were listed via the arguments (if there are more than 1).

public function __construct(EntityManager $entityManager) {
    $this->em = $entityManager;
}

回答3:

Note as of Symfony 3.3 EntityManager is depreciated. Use EntityManagerInterface instead.

namespace AppBundle\Service;

use Doctrine\ORM\EntityManagerInterface;

class Someclass {
    protected $em;

    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->em = $entityManager;
    }

    public function somefunction() {
        $em = $this->em;
        ...
    }
}

回答4:

Since 2017 and Symfony 3.3 you can register Repository as service, with all its advantages it has.

Check my post How to use Repository with Doctrine as Service in Symfony for more general description.

---

To your specific case, original code with tuning would look like this:

1. Use in your services or Controller

<?php

namespace Test\CommonBundle\Services;

use Doctrine\ORM\EntityManagerInterface;

class UserService
{
    private $userRepository;

    // use custom repository over direct use of EntityManager
    // see step 2
    public function __constructor(UserRepository $userRepository)
    {
        $this->userRepository = $userRepository;
    }

    public function getUser($userId)
    {
        return $this->userRepository->find($userId);
    }
}

2. Create new custom repository

<?php

namespace Test\CommonBundle\Repository;

use Doctrine\ORM\EntityManagerInterface;

class UserRepository
{
    private $repository;

    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->repository = $entityManager->getRepository(UserEntity::class);
    }

    public function find($userId)
    {
        return  $this->repository->find($userId);
    }
}

3. Register services

# app/config/services.yml
services:
    _defaults:
        autowire: true

    Test\CommonBundle\:
       resource: ../../Test/CommonBundle