Symfony 4 从 daabase 获取数据

Thx to this answer问题已经解决：Symfony 4和Doctrine，如何在映射后自动生成存储库？

我在从 MySQL 表中获取数据时遇到问题，

这是我的控制器：

namespace App\Controller\Admin;

use Symfony\Component\Routing\Annotation\Route;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\Extension\Core\Type\TextareaType;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use App\Entity\EmailComponents;

class MigrationController extends AbstractController
{

/**
 * @Route("/migration", name="migration_script")
 */
public function index(Request $request)
{
    $entityManager = $this -> getDoctrine() -> getManager();

    $email = new EmailComponents();

    $form = $this->createFormBuilder($email)
        ->add('language', ChoiceType::class, [
            'choices' => [
                'Anglais' => 'en',
                'Français' => 'fr',
                'Allemend' => 'de',
                'Néerlandais' => 'nl',
            ],
            ])
        ->add('subject', TextType::class)
        ->add('body', TextareaType::class)
        ->add('save', SubmitType::class, ['label' => 'Crée Email'])
        ->getForm();

    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        $email = $form->getData();
        $entityManager -> persist($email);
        $entityManager -> flush();

        $this->addFlash('success', 'Email a été crée avec succès');

        return $this -> redirectToRoute('migration_script');
    }


    $search = $entityManager -> getRepository(EmailComponents::class) -> findAll();

    return $this->render('admin/migration/index.html.twig', array(
        'form' => $form -> createView()
    ));
}

这是 EmailComponents.php 文件：

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;


/**
 * @ORM\Entity(repositoryClass="App\Repository\EmailComponentRepository")
 */
class EmailComponents
{
/**
 * @ORM\Id
 * @ORM\GeneratedValue
 * @ORM\Column(type="integer")
 */
private $id;

/**
 * @ORM\Column(type="string", length=2)
 */
private $language;

/**
 * @ORM\Column(type="string", length=250)
 */
private $subject;

/**
 * @ORM\Column(type="string", length=5000)
 */
private $body;


public function getId()
{
    return $this->id;
}

public function setId($id)
{
    $this->id = $id;
}

public function getLanguage()
{
    return $this->language;
}

public function setLanguage($language)
{
    $this->language = $language;
}

public function getSubject()
{
    return $this->subject;
}

public function setSubject($subject)
{
    $this->subject = $subject;
}

public function getBody()
{
    return $this->body;
}

public function setBody($body)
{
    $this->body = $body;
}
}

问题是每次运行页面时，都会收到以下错误消息：

“App\Entity\EmailComponents”实体的 repositoryClass 设置为“App\Repository\EmailComponentRepository”，但这不是有效的类。检查您的类命名。如果这是一个服务 ID，请确保此服务存在并标记为“doctrine.repository_service”。

错误来自这部分：

$search = $entityManager -> getRepository(EmailComponents::class) -> findAll();