[PR例] こんな感じに実装しました。

src/Controller/ArticlesController.php

@@ -3,26 +3,35 @@
 namespace App\Controller;
 
 use App\Entity\Article;
-use App\Entity\PostCount;
 use App\Form\ArticleType;
-use App\Repository\PostCountRepository;
-use DateTime;
-use Exception;
+use App\Service\ArticleService;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Annotation\Route;
+use Throwable;
 
 class ArticlesController extends AbstractController
 {
+    /** @var ArticleService  */
+    private $articleService;
+
+    /**
+     * ArticlesController constructor.
+     * @param ArticleService $articleService
+     */
+    public function __construct(ArticleService $articleService)
+    {
+        $this->articleService = $articleService;
+    }
+
     /**
      * @Route("/articles", name="articles")
      */
     public function index()
     {
-        $articleRepository = $this->getDoctrine()->getRepository(Article::class);
-        $articles = $articleRepository->findAll();
+        $articles = $this->articleService->getList();
         return $this->render('articles/index.html.twig', [
             'articles' => $articles,
         ]);
@@ -32,7 +41,7 @@ public function index()
      * @Route("/articles/new", name="articles_new")
      * @param Request $request
      * @return RedirectResponse|Response
-     * @throws Exception
+     * @throws Throwable
      */
     public function new(Request $request)
     {
@@ -42,20 +51,7 @@ public function new(Request $request)
         $form->handleRequest($request);
         if ($form->isSubmitted() && $form->isValid()) {
             $article = $form->getData();
-            $entityManager = $this->getDoctrine()->getManager();
-            $entityManager->persist($article);
-            /** @var PostCountRepository $postCountRepository */
-            $postCountRepository = $this->getDoctrine()->getRepository(PostCount::class);
-            $postCount = $postCountRepository->findOneBy([
-                'postDate' => new DateTime(),
-            ]);
-            if (empty($postCount)) {
-                $postCount = new PostCount();
-                $postCount->setPostDate(new DateTime());
-                $entityManager->persist($postCount);
-            }
-            $postCount->setPostCount($postCount->getPostCount() + 1);
-            $entityManager->flush();
+            $this->articleService->add($article);
 
             $this->addFlash('success', '登録しました');
             return $this->redirectToRoute('articles');

src/Entity/Article.php

@@ -2,6 +2,7 @@
 
 namespace App\Entity;
 
+use DateTime;
 use DateTimeInterface as DateTimeInterfaceAlias;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Validator\Constraints as Assert;
@@ -95,7 +96,7 @@ public function setUpdatedAt(DateTimeInterfaceAlias $updatedAt): self
      */
     public function prePersist()
     {
-        $now = new \DateTime();
+        $now = new DateTime();
         $this->setCreatedAt($now);
         $this->setUpdatedAt($now);
     }

src/Entity/PostCount.php

@@ -2,6 +2,7 @@
 
 namespace App\Entity;
 
+use DateTimeInterface;
 use Doctrine\ORM\Mapping as ORM;
 
 /**
@@ -34,12 +35,12 @@ public function getId(): ?int
         return $this->id;
     }
 
-    public function getPostDate(): ?\DateTimeInterface
+    public function getPostDate(): ?DateTimeInterface
     {
         return $this->postDate;
     }
 
-    public function setPostDate(\DateTimeInterface $postDate): self
+    public function setPostDate(DateTimeInterface $postDate): self
     {
         $this->postDate = $postDate;
 
@@ -57,4 +58,9 @@ public function setPostCount(int $postCount): self
 
         return $this;
     }
+
+    public function incrementPostCount(): void
+    {
+        $this->postCount++;
+    }
 }

src/Repository/ArticleRepository.php

@@ -4,6 +4,7 @@
 
 use App\Entity\Article;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\ORM\ORMException;
 use Doctrine\Persistence\ManagerRegistry;
 
 /**
@@ -19,6 +20,15 @@ public function __construct(ManagerRegistry $registry)
         parent::__construct($registry, Article::class);
     }
 
+    /**
+     * @param Article $article
+     * @throws ORMException
+     */
+    public function add(Article $article)
+    {
+        $this->getEntityManager()->persist($article);
+    }
+
     // /**
     //  * @return Article[] Returns an array of Article objects
     //  */

src/Repository/PostCountRepository.php

@@ -4,6 +4,7 @@
 
 use App\Entity\PostCount;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\ORM\ORMException;
 use Doctrine\Persistence\ManagerRegistry;
 
 /**
@@ -19,6 +20,15 @@ public function __construct(ManagerRegistry $registry)
         parent::__construct($registry, PostCount::class);
     }
 
+    /**
+     * @param PostCount $postCount
+     * @throws ORMException
+     */
+    public function add(PostCount $postCount)
+    {
+        $this->getEntityManager()->persist($postCount);
+    }
+
     // /**
     //  * @return PostCount[] Returns an array of PostCount objects
     //  */

src/Service/ArticleService.php

@@ -0,0 +1,78 @@
+<?php
+
+
+namespace App\Service;
+
+
+use App\Entity\Article;
+use App\Entity\PostCount;
+use App\Repository\ArticleRepository;
+use App\Repository\PostCountRepository;
+use DateTime;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\ORMException;
+use Throwable;
+
+class ArticleService
+{
+    /** @var EntityManagerInterface */
+    private $entityManager;
+    /** @var ArticleRepository  */
+    private $articleRepository;
+    /** @var PostCountRepository  */
+    private $postCountRepository;
+
+    /**
+     * ArticleService constructor.
+     * @param EntityManagerInterface $entityManager
+     * @param ArticleRepository $articleRepository
+     * @param PostCountRepository $postCountRepository
+     */
+    public function __construct(EntityManagerInterface $entityManager, ArticleRepository $articleRepository, PostCountRepository $postCountRepository)
+    {
+        $this->entityManager = $entityManager;
+        $this->articleRepository = $articleRepository;
+        $this->postCountRepository = $postCountRepository;
+    }
+
+    /**
+     * @return Article[]
+     */
+    public function getList()
+    {
+        return $this->articleRepository->findAll();
+    }
+
+    /**
+     * @param Article $article
+     * @throws Throwable
+     */
+    public function add(Article $article)
+    {
+        $this->entityManager->transactional(function () use ($article) {
+            $this->articleRepository->add($article);
+            $today = new DateTime();
+            $postCount = $this->getPostCountOrCreate($today);
+            $postCount->incrementPostCount();
+        });
+    }
+
+    /**
+     * @param DateTime $dateTime
+     * @return PostCount|null
+     * @throws ORMException
+     */
+    private function getPostCountOrCreate(DateTime $dateTime)
+    {
+        $postCount = $this->postCountRepository->findOneBy([
+            'postDate' => $dateTime,
+        ]);
+        if (empty($postCount)) {
+            $postCount = new PostCount();
+            $postCount->setPostDate($dateTime);
+            $this->postCountRepository->add($postCount);
+        }
+
+        return $postCount;
+    }
+}