[main ← Feature/top3] 좋아요 수 기준 랭킹 Top3 부스를 반환하는 API 작성

src/main/java/kr/co/knuserver/application/booth/BoothLikeService.java

@@ -84,6 +84,15 @@ public Set<ZSetOperations.TypedTuple<String>> getRanking() {
         }
     }
 
+    public Set<ZSetOperations.TypedTuple<String>> getTopRanking(int limit) {
+        try {
+            return redisTemplate.opsForZSet().reverseRangeWithScores(RANKING_KEY, 0, limit - 1);
+        } catch (DataAccessException e) {
+            log.warn("[Ranking] Redis 조회 실패, 빈 셋 반환", e);
+            return Collections.emptySet();
+        }
+    }
+
     private int getLikeMultiplier() {
         if (!doubleEventEnabled) {
             return 1;

src/main/java/kr/co/knuserver/application/booth/BoothQueryService.java

@@ -17,6 +17,7 @@
 import kr.co.knuserver.presentation.booth.dto.BoothInfoResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothListResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothRankingResponseDto;
+import kr.co.knuserver.presentation.booth.dto.BoothTop3ResponseDto;
 import org.springframework.data.redis.core.ZSetOperations;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.PageRequest;
@@ -96,7 +97,31 @@ public List<BoothRankingResponseDto> getBoothRanking() {
             .toList();
     }
 
-
+    public List<BoothTop3ResponseDto> getTop3BoothRanking() {
+        Set<ZSetOperations.TypedTuple<String>> rawRanking = boothLikeService.getTopRanking(10);
+        if (rawRanking == null || rawRanking.isEmpty()) {
+            return List.of();
+        }
+
+        BoothRanking boothRanking = new BoothRanking(rawRanking);
+        if (boothRanking.isEmpty()) {
+            return List.of();
+        }
+
+        List<Booth> booths = boothRepository.findAllById(boothRanking.boothIds());
+
+        return booths.stream()
+            .map(booth -> new BoothTop3ResponseDto(
+                booth.getId(),
+                booth.getName(),
+                boothRanking.getLikeCount(booth.getId())
+            ))
+            .sorted(Comparator.comparingLong(BoothTop3ResponseDto::likeCount).reversed()
+                .thenComparingLong(BoothTop3ResponseDto::boothId))
+            .limit(3)
+            .toList();
+    }
+
     public CursorPaginationResponse<BoothListResponseDto> searchBoothsByKeyword2(String keyword, Long lastId, int size) {
         Pageable pageable = PageRequest.of(0, size + 1);
         List<Booth> booths;

src/main/java/kr/co/knuserver/presentation/booth/BoothApiController.java

@@ -11,6 +11,7 @@
 import kr.co.knuserver.presentation.booth.dto.BoothInfoResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothListResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothRankingResponseDto;
+import kr.co.knuserver.presentation.booth.dto.BoothTop3ResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothUpdateRequestDto;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.HttpStatus;
@@ -80,9 +81,17 @@ public ResponseEntity<ApiResponse<CursorPaginationResponse<BoothListResponseDto>
             .body(ApiResponse.success(result));
     }
 
+    @Override
     @GetMapping("/ranking")
     public ResponseEntity<ApiResponse<List<BoothRankingResponseDto>>> getBoothRanking() {
         List<BoothRankingResponseDto> result = boothQueryService.getBoothRanking();
         return ResponseEntity.ok(ApiResponse.success(result));
     }
+
+    @Override
+    @GetMapping("/ranking/top3")
+    public ResponseEntity<ApiResponse<List<BoothTop3ResponseDto>>> getTop3BoothRanking() {
+        List<BoothTop3ResponseDto> result = boothQueryService.getTop3BoothRanking();
+        return ResponseEntity.ok(ApiResponse.success(result));
+    }
 }

src/main/java/kr/co/knuserver/presentation/booth/docs/BoothApiControllerDocs.java

@@ -11,6 +11,8 @@
 import kr.co.knuserver.presentation.booth.dto.BoothCountResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothInfoResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothListResponseDto;
+import kr.co.knuserver.presentation.booth.dto.BoothRankingResponseDto;
+import kr.co.knuserver.presentation.booth.dto.BoothTop3ResponseDto;
 import kr.co.knuserver.presentation.booth.dto.BoothUpdateRequestDto;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -60,4 +62,16 @@ ResponseEntity<kr.co.knuserver.global.exception.ApiResponse<CursorPaginationResp
         @Parameter(description = "페이지 크기 (기본값: 10)")
         @RequestParam(name = "size", required = false, defaultValue = "10") int size
     );
+
+    @Operation(summary = "가두모집 부스 좋아요 랭킹 전체 조회", description = "좋아요 수 기준 전체 부스 랭킹을 반환합니다.")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "200", description = "랭킹 조회 성공")
+    })
+    ResponseEntity<kr.co.knuserver.global.exception.ApiResponse<List<BoothRankingResponseDto>>> getBoothRanking();
+
+    @Operation(summary = "가두모집 부스 좋아요 TOP 3 조회", description = "좋아요 수 기준 상위 3개 부스를 반환합니다.")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "200", description = "TOP 3 랭킹 조회 성공")
+    })
+    ResponseEntity<kr.co.knuserver.global.exception.ApiResponse<List<BoothTop3ResponseDto>>> getTop3BoothRanking();
 }

src/main/java/kr/co/knuserver/presentation/booth/dto/BoothTop3ResponseDto.java

@@ -0,0 +1,7 @@
+package kr.co.knuserver.presentation.booth.dto;
+
+public record BoothTop3ResponseDto(
+    Long boothId,
+    String boothName,
+    long likeCount
+) {}