Refactor/조회수 리팩토링

src/main/java/com/hf/healthfriend/HealthfriendApplication.java

@@ -2,8 +2,10 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.scheduling.annotation.EnableScheduling;
 
 @SpringBootApplication
+@EnableScheduling
 public class HealthfriendApplication {
 
 	public static void main(String[] args) {

src/main/java/com/hf/healthfriend/domain/like/service/LikeService.java

@@ -60,7 +60,6 @@ public Long addPostLike(Long memberId, Long postId) throws DuplicatePostLikeExce
             );
             try {
                 Like savedLike = this.likeRepository.save(like);
-                // TODO 동시성 처리 필요
                 postRepository.incrementLikeCount(postId);
                 notificationPublishService.publishPostLikeNot(memberId, postId);
                 savePopularPost(postId);
@@ -75,7 +74,6 @@ public Long addPostLike(Long memberId, Long postId) throws DuplicatePostLikeExce
                 throw new DuplicatePostLikeException(postId, memberId);
             }
             like.uncancel();
-            // TODO 동시성 처리 필요
             postRepository.incrementLikeCount(postId);
             savePopularPost(postId);
             notificationPublishService.publishPostLikeNot(memberId, postId);

src/main/java/com/hf/healthfriend/domain/post/dto/response/PostGetResponse.java

@@ -24,7 +24,7 @@ public record PostGetResponse(
         Long commentCount,
         List<CommentDto> comments
 ) {
-    public static PostGetResponse of(Post post, List<CommentDto> comments, String imagePath, String writerProfileImageUrl) {
+    public static PostGetResponse of(Post post, List<CommentDto> comments,Long viewCountFromRedis ,String imagePath, String writerProfileImageUrl) {
         return PostGetResponse.builder()
                 .postId(post.getPostId())
                 .writerId(post.getMember().getId())
@@ -36,7 +36,7 @@ public static PostGetResponse of(Post post, List<CommentDto> comments, String im
                 .content(post.getContent())
                 .imagePath(imagePath)
                 .createDate(post.getCreationTime())
-                .viewCount(post.getViewCount())
+                .viewCount(viewCountFromRedis)
                 .likeCount(post.getLikesCount())
                 .commentCount(post.getCommentsCount())
                 .comments(comments)

src/main/java/com/hf/healthfriend/domain/post/dto/response/PostListObject.java

@@ -19,12 +19,12 @@ public record PostListObject(
         String fitnessLevel,
         String writerProfileImageUrl
 ) {
-    public static PostListObject of(Post post, String content, FileUrlResolver fileUrlResolver) {
+    public static PostListObject of(Post post, String content, FileUrlResolver fileUrlResolver, long viewCountFromRedis) {
         return PostListObject.builder()
                 .postId(post.getPostId())
                 .title(post.getTitle())
                 .category(post.getCategory().name())
-                .viewCount(post.getViewCount())
+                .viewCount(viewCountFromRedis)
                 .creationTime(post.getCreationTime())
                 .content(content)
                 .fitnessLevel(post.getMember().getFitnessLevel().name())

src/main/java/com/hf/healthfriend/domain/post/entity/Post.java

@@ -77,8 +77,8 @@ public void update(String title, String content, PostCategory category) {
         this.category = category;
     }
 
-    public void updateViewCount(Long viewCount) {
-        this.viewCount = viewCount+1;
+    public void updateViewCount(long newViewCount) {
+        this.viewCount = newViewCount;
     }
 
 

src/main/java/com/hf/healthfriend/domain/post/repository/querydsl/PostCustomRepositoryImpl.java

@@ -3,14 +3,18 @@
 import com.hf.healthfriend.domain.member.constant.FitnessLevel;
 import com.hf.healthfriend.domain.post.constant.PostCategory;
 import com.hf.healthfriend.domain.post.dto.response.PostListObject;
+import com.hf.healthfriend.domain.post.entity.Post;
 import com.hf.healthfriend.domain.post.entity.QPost;
 import com.hf.healthfriend.global.file.FileUrlResolver;
 import com.querydsl.core.BooleanBuilder;
 import com.querydsl.core.types.Order;
 import com.querydsl.core.types.OrderSpecifier;
 import com.querydsl.core.types.dsl.Expressions;
 import com.querydsl.jpa.impl.JPAQueryFactory;
+import java.util.HashMap;
+import java.util.Map;
 import lombok.RequiredArgsConstructor;
+import org.redisson.api.RedissonClient;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Repository;
 
@@ -20,6 +24,7 @@
 @RequiredArgsConstructor
 public class PostCustomRepositoryImpl implements PostCustomRepository {
 
+    private final RedissonClient redissonClient;
     private final FileUrlResolver fileUrlResolver;
     private final JPAQueryFactory queryFactory;
     private final QPost post = QPost.post;
@@ -28,49 +33,36 @@ public class PostCustomRepositoryImpl implements PostCustomRepository {
     public List<PostListObject> getList(FitnessLevel fitnessLevel, PostCategory postCategory, String keyword, Pageable pageable) {
         OrderSpecifier<?> orderSpecifier = new OrderSpecifier<>(Order.DESC, post.creationTime);
         BooleanBuilder builder = filter(fitnessLevel, postCategory, keyword);
-        return  queryFactory
+
+        List<Post> posts = queryFactory
                 .selectFrom(post)
                 .where(builder)
                 .groupBy(post)
                 .orderBy(orderSpecifier)
                 .offset(pageable.getOffset())
                 .limit(pageable.getPageSize())
-                .fetch()
-                .stream().map(post-> {
-                    String content = post.getContent();
-                    if (keyword!=null){
-                        String sentence = getSentenceContainKeyword(keyword,post.getContent());
-                        content = (sentence!=null)?sentence:content;
-                    }
-                    return PostListObject.of(post,content,fileUrlResolver);
-                }).toList();
+                .fetch();
+
+        return convertPostsToDto(posts, keyword);
     }
 
     @Override
     public List<PostListObject> getPopularList(List<Long> postIdList, FitnessLevel fitnessLevel, String keyword, Pageable pageable) {
         BooleanBuilder builder = filter(fitnessLevel, null, keyword);
         OrderSpecifier<?>[] orderSpecifier = new OrderSpecifier<?>[]{
-                /* 어차피 sortedSet 에서 정렬돼있기 때문에 실제론 수행되지 않는다.
-                2차로 최신순 정렬을 수행하려고 쓸 뿐이다.
-                 */
                 new OrderSpecifier<>(Order.DESC, post.likesCount),
                 new OrderSpecifier<>(Order.DESC, post.creationTime)
         };
-        return  queryFactory
+
+        List<Post> posts = queryFactory
                 .selectFrom(post)
                 .where(post.postId.in(postIdList).and(builder))
                 .orderBy(orderSpecifier)
                 .offset(pageable.getOffset())
                 .limit(pageable.getPageSize())
-                .fetch()
-                .stream().map(post-> {
-                    String content = post.getContent();
-                    if (keyword!=null){
-                        String sentence = getSentenceContainKeyword(keyword,post.getContent());
-                        content = (sentence!=null)?sentence:content;
-                    }
-                    return PostListObject.of(post,content,fileUrlResolver);
-                }).toList();
+                .fetch();
+
+        return convertPostsToDto(posts, keyword);
     }
 
     @Override
@@ -124,4 +116,31 @@ public Long getTotalPageSize(int size){
         if (totalPageSize == null) return 0L;
         return (long) Math.ceil((double) totalPageSize / size);
     }
+
+    private Map<Long, Long> getViewCountsFromRedis(List<Post> posts) {
+        Map<Long, Long> viewCountsFromRedis = new HashMap<>();
+        // getBuckets()로 키를 한 번에 조회해와 네트워크 I/O를 줄임
+        Map<String, Long> redisValues = redissonClient.getBuckets().get(posts.stream()
+                .map(post -> "post:viewCount:" + post.getPostId())
+                .toArray(String[]::new));
+
+        for (Post post : posts) {
+            viewCountsFromRedis.put(post.getPostId(), redisValues.getOrDefault("post:viewCount:" + post.getPostId(), 0L));
+        }
+
+        return viewCountsFromRedis;
+    }
+
+    private List<PostListObject> convertPostsToDto(List<Post> posts, String keyword) {
+        Map<Long, Long> viewCounts = getViewCountsFromRedis(posts);
+
+        return posts.stream().map(post -> {
+            String content = post.getContent();
+            if (keyword != null) {
+                String sentence = getSentenceContainKeyword(keyword, post.getContent());
+                content = (sentence != null) ? sentence : content;
+            }
+            return PostListObject.of(post, content, fileUrlResolver, viewCounts.getOrDefault(post.getPostId(), 0L));
+        }).toList();
+    }
 }

src/main/java/com/hf/healthfriend/domain/post/service/PostBatchService.java

@@ -0,0 +1,71 @@
+package com.hf.healthfriend.domain.post.service;
+
+
+import com.hf.healthfriend.domain.post.entity.Post;
+import com.hf.healthfriend.domain.post.repository.PostRepository;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.StreamSupport;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.redisson.api.RKeys;
+import org.redisson.api.RedissonClient;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class PostBatchService {
+
+    private final RedissonClient redissonClient;
+    private final PostRepository postRepository;
+
+    private static final String VIEW_COUNT_PREFIX = "post:viewCount:";
+
+    @Transactional
+    @Scheduled(fixedRate = 1000*60*60*24) // 24시간 주기
+    public void syncVIewCountsToDB(){
+        log.info("Redis 조회수를 DB로 동기화 시작");
+
+        // 1. Redis 에 저장된 조회수 key 찾기
+        RKeys keys = redissonClient.getKeys();
+        Iterable<String> redisKeysIterable = keys.getKeysByPattern(VIEW_COUNT_PREFIX + "*");
+        Set<String> redisKeys = StreamSupport.stream(redisKeysIterable.spliterator(), false)
+                .collect(Collectors.toSet());
+
+        if (redisKeys.isEmpty()) {
+            log.info("저장된 조회수가 없어 동기화를 종료합니다.");
+        }else{
+            // Redis 에서 모든 조회수를 가져와서 postId 별로 매핑
+            Map<Long, Long> viewCounts = redisKeys.stream()
+                    .collect(Collectors.toMap(
+                            key -> Long.parseLong(key.replace(VIEW_COUNT_PREFIX, "")), // postId 추출
+                            key -> redissonClient.getAtomicLong(key).get() // 조회수 가져오기
+                    ));
+
+            // DB 에서 해당 postId 목록 가져오기
+            List<Post> posts = postRepository.findAllById(viewCounts.keySet());
+
+            for (Post post : posts) {
+                Long redisViewCount = viewCounts.get(post.getPostId());
+
+                if (redisViewCount != null && redisViewCount > post.getViewCount()) {
+                    log.info("postId={} 조회수 업데이트: DB={}, Redis={}",
+                            post.getPostId(), post.getViewCount(), redisViewCount);
+                    post.updateViewCount(redisViewCount);
+                }
+            }
+
+            postRepository.saveAll(posts); // 일괄 저장
+
+            // 동기화 후 Redis 에서 조회수 초기화
+            redisKeys.forEach(key -> redissonClient.getAtomicLong(key).delete());
+
+            log.info("Redis 조회수를 DB로 동기화 완료");
+        }
+    }
+}

src/main/java/com/hf/healthfriend/domain/post/service/PostService.java

@@ -19,8 +19,11 @@
 import com.hf.healthfriend.domain.post.repository.PostRepository;
 import com.hf.healthfriend.global.file.FileUrlResolver;
 import jakarta.transaction.Transactional;
+import java.time.Duration;
+import java.util.concurrent.TimeUnit;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.redisson.api.RAtomicLong;
 import org.redisson.api.RScoredSortedSet;
 import org.redisson.api.RedissonClient;
 import org.springframework.data.domain.Pageable;
@@ -62,20 +65,24 @@ public Long update(PostWriteRequest postWriteRequest, Long postId){
 
     public PostGetResponse get(Long postId, boolean canUpdateViewCount, CommentSortType sortType) {
         Post post = postRepository.findByPostIdAndIsDeletedFalse(postId)
-                .orElseThrow(() -> new PostException(PostErrorCode.POST_NOT_FOUND, HttpStatus.NOT_FOUND,postId + "번 post가 존재하지 않습니다."));
-        if(canUpdateViewCount) {
-            post.updateViewCount(post.getViewCount());
-        }
-        List<CommentDto> commentList = commentService.getCommentsOfPost(postId,sortType);
+                .orElseThrow(() -> new PostException(PostErrorCode.POST_NOT_FOUND, HttpStatus.NOT_FOUND, postId + "번 post가 존재하지 않습니다."));
+
+        long viewCount = increaseViewCount(postId,post,canUpdateViewCount);
+        List<CommentDto> commentList = commentService.getCommentsOfPost(postId, sortType);
+
         String imagePath = fileUrlResolver.resolveFileUrl(post.getImagePath());
         String writerProfileImageUrl = fileUrlResolver.resolveFileUrl(post.getMember().getProfileImageUrl());
-        return PostGetResponse.of(post, commentList,imagePath, writerProfileImageUrl);
+
+        return PostGetResponse.of(post, commentList, viewCount, imagePath, writerProfileImageUrl);
     }
 
     public void delete(Long postId) {
         Post post = postRepository.findByPostIdAndIsDeletedFalse(postId)
                 .orElseThrow(() -> new PostException(PostErrorCode.POST_NOT_FOUND, HttpStatus.NOT_FOUND,postId + "번 post가 존재하지 않습니다."));
         post.delete();
+        // Redis 에서도 조회수 제거
+        String redisKey = "post:viewCount:" + postId;
+        redissonClient.getAtomicLong(redisKey).delete();
         likeRepository.deleteLikeByPostId(postId);
     }
 
@@ -101,7 +108,27 @@ public PostSearchResponse getPopularList(int pageNumber, int size, FitnessLevel
                 .build();
     }
 
+    private Long increaseViewCount(Long postId, Post post, boolean canUpdateViewCount) {
+        String redisKey = "post:viewCount:" + postId;
+        RAtomicLong counter = redissonClient.getAtomicLong(redisKey);
 
-}
+        long viewCount = counter.get();
 
+        // 값이 없으면 DB 값으로 초기화 + TTL 6시간
+        if (viewCount == 0) {
+            viewCount = post.getViewCount();
+            counter.set(viewCount);
+            counter.expire(Duration.ofHours(6));
+            log.info("Redis에 조회수 초기화: postId={}, newViewCount={}", postId, viewCount);
+        }
+
+        // 조회수 증가 + TTL 연장
+        if (canUpdateViewCount) {
+            viewCount = counter.incrementAndGet();
+            counter.expire(Duration.ofHours(6));  // 연장
+            log.info("조회수 증가: postId={}, newViewCount={}", postId, viewCount);
+        }
 
+        return viewCount;
+    }
+}