php - 使用 `must implement interface Doctrine\ORM\EntityManagerInterface error` 将 EntityManagerInterface 注入(inject)我的服务

Question

我在 ./src/Service 创建了一个服务，我想在我的服务中使用 Doctrine Entity Manager，所以我将它注入(inject)到 __construct方法:

命名空间应用\服务；

use App\Entity\Category;
use Doctrine\ORM\EntityManagerInterface;
use Twig\Environment;
use Twig\Error\LoaderError;
use Twig\Error\RuntimeError;
use Twig\Error\SyntaxError;

class CommonPageGenerator
{
  /**
   * @var EntityManagerInterface
   */
  private $em;
  /**
   * @var Environment
   */
  private $templating;

  public function __construct(EntityManagerInterface $em, Environment $templating)
  {
    $this->em = $em;
    $this->templating = $templating;
  }

  public function page1($title){ return; }

}

然后我将此服务注入(inject) Controller 中:

  /**
   * @Route("/overseas", name="overseas")
   * @param CommonPageGenerator $commonPageGenerator
   */
  public function overseas(CommonPageGenerator $commonPageGenerator)
  {
    return $commonPageGenerator->page1('overseas');
  }

但我收到以下错误:

Argument 1 passed to App\Service\CommonPageGenerator::__construct() must implement interface Doctrine\ORM\EntityManagerInterface, string given, called in /Users/tangmonk/Documents/mygit/putixin.com/putixin_backend/var/cache/dev/ContainerB7I3rzx/getCommonPageGeneratorService.php on line 11

我的 services.yaml文件:

parameters:

services:
    # default configuration for services in *this* file
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.
        autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
        bind:
          $em: 'doctrine.orm.default_entity_manager'

我正在使用 Symfony 4.3

Answer 1

您不需要绑定(bind)$em给 Doctrine 实体经理。

如果您删除该行并仅保留类型提示( __construct(EntityManagerInterface $em, Environment $templating )就足够了。

从而留下您的__construct()像这样的方法:

// you can of course import the EngineInterface with a "use" statement. 
public function __construct(
                    EntityManagerInterface $em,
                    Environment $templating)
  {
    $this->em = $em;
    $this->templating = $templating;
  }

如果你这样做， 删除 绑定(bind)配置，自动依赖注入(inject)应该自己工作。

(通常我会建议将 Environment 替换为 Symfony\Bundle\FrameworkBundle\Templating\EngineInterface ，以依赖于框架提供的接口(interface)以与模板组件集成。但是 this component and its integration have been deprecated in 4.3 ，并且将在 5.0 中删除；所以你可以直接依赖于枝条。)

但如果出于某种原因想要保留绑定(bind)，则应在服务名称前加上 @符号，因此 Symfony 知道您正在尝试注入(inject)服务而不是字符串。像这样:

 bind:
          $em: '@doctrine.orm.default_entity_manager'

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