feat: 해시태그를 리스트로 변경한다

Author: NaMinhyeok

src/main/java/spring/memewikibe/api/controller/meme/response/MemeDetailResponse.java

@@ -1,5 +1,8 @@
 package spring.memewikibe.api.controller.meme.response;
 
+import spring.memewikibe.common.util.HashtagParser;
+import spring.memewikibe.domain.meme.Meme;
+
 import java.util.List;
 import java.util.Objects;
 
@@ -10,9 +13,21 @@ public record MemeDetailResponse(
     String origin,
     String trendPeriod,
     String imgUrl,
-    String hashtags
+    List<String> hashtags
 ) {
     public MemeDetailResponse {
         Objects.requireNonNull(title, "제목은 필수입니다.");
     }
+
+    public static MemeDetailResponse from(Meme meme) {
+        return new MemeDetailResponse(
+            meme.getId(),
+            meme.getTitle(),
+            meme.getUsageContext(),
+            meme.getOrigin(),
+            meme.getTrendPeriod(),
+            meme.getImgUrl(),
+            HashtagParser.parseHashtags(meme.getHashtags())
+        );
+    }
 }

src/main/java/spring/memewikibe/application/MemeLookUpServiceImpl.java

@@ -76,13 +76,13 @@ public MemeDetailResponse getMemeById(Long id) {
 
         eventPublisher.publishEvent(new MemeViewedEvent(id));
 
-        return new MemeDetailResponse(meme.getId(), meme.getTitle(), meme.getUsageContext(), meme.getOrigin(), meme.getTrendPeriod(), meme.getImgUrl(), meme.getHashtags());
+        return MemeDetailResponse.from(meme);
     }
 
     private PageResponse<Cursor, MemeDetailResponse> createPageResponseBy(List<Meme> memes, int limit) {
         Cursor cursor = Cursor.of(memes, limit);
         List<MemeDetailResponse> response = memes.stream()
-            .map(it -> new MemeDetailResponse(it.getId(), it.getTitle(), it.getUsageContext(), it.getOrigin(), it.getTrendPeriod(), it.getImgUrl(), it.getHashtags()))
+            .map(MemeDetailResponse::from)
             .limit(limit)
             .toList();
         return PageResponse.cursor(cursor, response);

src/main/java/spring/memewikibe/common/util/HashtagParser.java

@@ -0,0 +1,25 @@
+package spring.memewikibe.common.util;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.util.Collections;
+import java.util.List;
+
+public class HashtagParser {
+    private static final ObjectMapper objectMapper = new ObjectMapper();
+
+    public static List<String> parseHashtags(String hashtagsJson) {
+        if (hashtagsJson == null || hashtagsJson.trim().isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        try {
+            return objectMapper.readValue(hashtagsJson, new TypeReference<>() {
+            });
+        } catch (JsonProcessingException e) {
+            return Collections.emptyList();
+        }
+    }
+}