feat: 게시글 추천 기능 구현

Author: seok6555

src/main/java/com/back/domain/post/comment/controller/CommentController.java

@@ -4,8 +4,6 @@
 import com.back.domain.post.comment.dto.request.CommentUpdateRequestDto;
 import com.back.domain.post.comment.dto.response.CommentResponseDto;
 import com.back.domain.post.comment.service.CommentService;
-import com.back.domain.post.post.dto.request.PostUpdateRequestDto;
-import com.back.domain.post.post.dto.response.PostResponseDto;
 import com.back.global.rsData.RsData;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;

src/main/java/com/back/domain/post/post/controller/PostController.java

@@ -95,4 +95,18 @@ public RsData<Void> deletePost(
     postService.deletePost(postId);
     return RsData.successOf(null); // code=200, message="success"
   }
+
+  /**
+   * 게시글 추천(좋아요) 토글 API
+   * @param postId 추천할 게시글 ID
+   * @return 추천 상태 변경 성공 메시지
+   */
+  @PostMapping("/{postId}/like")
+  @Operation(summary = "게시글 추천")
+  public RsData<Void> toggleLike(
+      @PathVariable Long postId
+  ) {
+    postService.toggleLike(postId);
+    return RsData.successOf(null); // code=200, message="success"
+  }
 }

src/main/java/com/back/domain/post/post/entity/Post.java

@@ -24,7 +24,6 @@
 import lombok.Builder;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import lombok.Setter;
 import org.springframework.data.annotation.CreatedDate;
 import org.springframework.data.annotation.LastModifiedDate;
 import org.springframework.data.jpa.domain.support.AuditingEntityListener;
@@ -83,6 +82,9 @@ public class Post {
   @OneToMany(mappedBy = "post", cascade = CascadeType.ALL, orphanRemoval = true)
   private List<PostTag> postTags = new ArrayList<>();
 
+  @OneToMany(mappedBy = "post", cascade = CascadeType.ALL, orphanRemoval = true)
+  private List<PostLike> postLikes = new ArrayList<>();
+
   // 게시글 추천 수 (기본값: 0)
   @Builder.Default
   @Column(name = "like_count", nullable = false)
@@ -124,4 +126,12 @@ public void addTag(Tag tag) {
   public void clearTags() {
     this.postTags.clear();
   }
+
+  public void increaseLikeCount() {
+    this.likeCount++;
+  }
+
+  public void decreaseLikeCount() {
+    this.likeCount--;
+  }
 }

src/main/java/com/back/domain/post/post/entity/PostLike.java

@@ -0,0 +1,65 @@
+package com.back.domain.post.post.entity;
+
+import com.back.domain.post.post.enums.PostLikeStatus;
+import com.back.domain.user.entity.User;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.EntityListeners;
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
+import java.time.LocalDateTime;
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.jpa.domain.support.AuditingEntityListener;
+
+@Entity
+@Getter
+// 같은 사용자(user_id)가 같은 게시글(post_id)을 중복 추천하지 못하도록 DB 레벨에서 보장.
+@Table(name = "post_like", uniqueConstraints = {
+    @UniqueConstraint(columnNames = {"post_id", "user_id"})
+})
+@EntityListeners(AuditingEntityListener.class)
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+@Builder
+public class PostLike {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  @Column(name = "id")
+  private Long id;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "post_id")
+  private Post post;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "user_id")
+  private User user;
+
+  // 추천 생성 날짜
+  @CreatedDate
+  private LocalDateTime createdAt;
+
+  // 추천 상태 (기본값: 비추천)
+  @Builder.Default
+  @Enumerated(EnumType.STRING)
+  @Column(name = "status", nullable = false)
+  private PostLikeStatus status = PostLikeStatus.NONE;
+
+  public void updateStatus(PostLikeStatus status) {
+    this.status = status;
+  }
+}

src/main/java/com/back/domain/post/post/enums/PostLikeStatus.java

@@ -0,0 +1,14 @@
+package com.back.domain.post.post.enums;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum PostLikeStatus {
+  NONE("비추천", "해당 게시글에 추천을 아직 누르지 않은 상태"),
+  LIKE("추천", "해당 게시글에 추천을 누른 상태");
+
+  private final String title;
+  private final String description;
+}

src/main/java/com/back/domain/post/post/repository/PostLikeRepository.java

@@ -0,0 +1,11 @@
+package com.back.domain.post.post.repository;
+
+import com.back.domain.post.post.entity.Post;
+import com.back.domain.post.post.entity.PostLike;
+import com.back.domain.user.entity.User;
+import java.util.Optional;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface PostLikeRepository extends JpaRepository<PostLike, Long> {
+  Optional<PostLike> findByPostAndUser(Post post, User user);
+}

src/main/java/com/back/domain/post/post/service/PostService.java

@@ -6,14 +6,18 @@
 import com.back.domain.post.post.dto.request.PostUpdateRequestDto;
 import com.back.domain.post.post.dto.response.PostResponseDto;
 import com.back.domain.post.post.entity.Post;
+import com.back.domain.post.post.entity.PostLike;
 import com.back.domain.post.post.entity.Tag;
+import com.back.domain.post.post.enums.PostLikeStatus;
 import com.back.domain.post.post.enums.PostStatus;
+import com.back.domain.post.post.repository.PostLikeRepository;
 import com.back.domain.post.post.repository.PostRepository;
 import com.back.domain.post.post.repository.TagRepository;
 import com.back.domain.user.entity.User;
 import com.back.global.rq.Rq;
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.Optional;
 import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
@@ -26,6 +30,7 @@ public class PostService {
   private final PostRepository postRepository;
   private final CategoryRepository categoryRepository;
   private final TagRepository tagRepository;
+  private final PostLikeRepository postLikeRepository;
   private final Rq rq;
 
   // 게시글 작성 로직
@@ -129,6 +134,32 @@ public void deletePost(Long postId) {
 //    postRepository.delete(post);
   }
 
+  @Transactional
+  public void toggleLike(Long postId) {
+    User user = rq.getActor(); // 현재 로그인한 사용자
+
+    Post post = postRepository.findById(postId)
+        .orElseThrow(() -> new NoSuchElementException("해당 게시글을 찾을 수 없습니다. ID: " + postId));
+
+    Optional<PostLike> existingLike = postLikeRepository.findByPostAndUser(post, user);
+
+    if (existingLike.isPresent()) {
+      // 이미 추천했으면 취소
+      existingLike.get().updateStatus(PostLikeStatus.NONE);
+      postLikeRepository.delete(existingLike.get());
+      post.decreaseLikeCount();
+    } else {
+      // 추천 추가
+      PostLike postLike = PostLike.builder()
+          .post(post)
+          .user(user)
+          .status(PostLikeStatus.LIKE)
+          .build();
+      postLikeRepository.save(postLike);
+      post.increaseLikeCount();
+    }
+  }
+
   // 태그 추가 메서드
   private void addTag(List<String> tagNames, Post post) {
     for (String tagName : tagNames) {

src/main/java/com/back/domain/user/entity/User.java

@@ -1,16 +1,27 @@
 package com.back.domain.user.entity;
 
-import jakarta.persistence.*;
-import lombok.*;
-import org.springframework.security.core.GrantedAuthority;
-import org.springframework.security.core.authority.SimpleGrantedAuthority;
-import org.springframework.data.annotation.CreatedDate;
-import org.springframework.data.annotation.LastModifiedDate;
-
+import com.back.domain.post.post.entity.PostLike;
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.springframework.data.annotation.CreatedDate;
+import org.springframework.data.annotation.LastModifiedDate;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
 
 @Entity
 @Table(name = "users")  // 예약어 충돌 방지를 위해 "users" 권장
@@ -51,6 +62,10 @@ public class User {
     @Column(nullable = false, length = 20)
     private String role = "USER";
 
+    // 양방향 매핑을 위한 필드
+    @OneToMany(mappedBy = "user", cascade = CascadeType.ALL, orphanRemoval = true)
+    private List<PostLike> postLikes = new ArrayList<>();
+
     public boolean isAdmin() {
         return "ADMIN".equalsIgnoreCase(role);
     }