[refactor] 나만의 bar 페이지네이션을 커서 기반으로 리팩토링 #49

src/main/java/com/back/domain/mybar/controller/MyBarController.java

@@ -9,6 +9,8 @@
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
+import org.springframework.format.annotation.DateTimeFormat;
+import java.time.LocalDateTime;
 
 @RestController
 @RequestMapping("/me/bar")
@@ -21,10 +23,12 @@ public class MyBarController {
     @GetMapping
     public RsData<MyBarListResponseDto> getMyBarList(
             @AuthenticationPrincipal(expression = "id") Long userId,
-            @RequestParam(defaultValue = "0") @Min(0) int page,
-            @RequestParam(defaultValue = "20") @Min(1) @Max(100) int pageSize
+            @RequestParam(required = false)
+            @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) LocalDateTime lastKeptAt,
+            @RequestParam(required = false) Long lastId,
+            @RequestParam(defaultValue = "20") @Min(1) @Max(100) int limit
     ) {
-        MyBarListResponseDto body = myBarService.getMyBar(userId, page, pageSize);
+        MyBarListResponseDto body = myBarService.getMyBar(userId, lastKeptAt, lastId, limit);
         return RsData.successOf(body);  // code=200, message="success"
     }
 

src/main/java/com/back/domain/mybar/dto/MyBarListResponseDto.java

@@ -3,12 +3,14 @@
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 
+import java.time.LocalDateTime;
 import java.util.List;
 
 @Getter
 @AllArgsConstructor
 public class MyBarListResponseDto {
     private List<MyBarItemResponseDto> items;
-    private boolean hasNext;   // 다음 페이지 존재 여부
-    private Integer nextPage;  // 다음 페이지 번호(없으면 null)
-}
+    private boolean hasNext;        // 다음 페이지 존재 여부
+    private LocalDateTime nextKeptAt; // 다음 페이지 시작용 keptAt
+    private Long nextId;              // 다음 페이지 시작용 id
+}

src/main/java/com/back/domain/mybar/repository/MyBarRepository.java

@@ -10,12 +10,23 @@
 import org.springframework.stereotype.Repository;
 
 import java.util.Optional;
+import java.util.List;
+import java.time.LocalDateTime;
 
 @Repository
 public interface MyBarRepository extends JpaRepository<MyBar, Long> {
     /** 나만의 bar(킵) 목록: ACTIVE만, id desc */
     Page<MyBar> findByUser_IdAndStatusOrderByKeptAtDescIdDesc(Long userId, KeepStatus status, Pageable pageable);
 
+    @Query("""
+        select m from MyBar m
+         where m.user.id = :userId
+           and m.status = :status
+           and (m.keptAt < :keptAt or (m.keptAt = :keptAt and m.id < :id))
+         order by m.keptAt desc, m.id desc
+    """)
+    List<MyBar> findSliceByCursor(Long userId, KeepStatus status, LocalDateTime keptAt, Long id, Pageable pageable);
+
     /** 프로필/요약용: ACTIVE 개수 */
     long countByUser_IdAndStatus(Long userId, KeepStatus status);
 

src/main/java/com/back/domain/mybar/service/MyBarService.java

@@ -10,6 +10,7 @@
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -26,18 +27,38 @@ public class MyBarService {
     private final UserRepository userRepository;
     private final CocktailRepository cocktailRepository;
 
+    // 커서: lastKeptAt + lastId를 그대로 파라미터로 사용
     @Transactional(readOnly = true)
-    public MyBarListResponseDto getMyBar(Long userId, int page, int pageSize) {
-        Page<MyBar> myBarPage = myBarRepository.findByUser_IdAndStatusOrderByKeptAtDescIdDesc(userId, KeepStatus.ACTIVE, PageRequest.of(page, pageSize));
+    public MyBarListResponseDto getMyBar(Long userId, LocalDateTime lastKeptAt, Long lastId, int limit) {
+        int safeLimit = Math.max(1, Math.min(limit, 100));
+        int fetchSize = safeLimit + 1; // 다음 페이지 여부 판단용으로 1개 더 조회
+
+        List<MyBar> rows;
+        Pageable pageable = PageRequest.of(0, fetchSize);
+
+        if (lastKeptAt == null || lastId == null) {
+            Page<MyBar> page0 = myBarRepository
+                    .findByUser_IdAndStatusOrderByKeptAtDescIdDesc(userId, KeepStatus.ACTIVE, pageable);
+            rows = page0.getContent();
+        } else {
+            rows = myBarRepository.findSliceByCursor(userId, KeepStatus.ACTIVE, lastKeptAt, lastId, pageable);
+        }
+
+        boolean hasNext = rows.size() > safeLimit;
+        if (hasNext) rows = rows.subList(0, safeLimit);
 
-        List<MyBar> myBars = myBarPage.getContent();
         List<MyBarItemResponseDto> items = new ArrayList<>();
-        for (MyBar myBar : myBars) items.add(MyBarItemResponseDto.from(myBar));
+        for (MyBar myBar : rows) items.add(MyBarItemResponseDto.from(myBar));
 
-        boolean hasNext = myBarPage.hasNext();
-        Integer nextPage = hasNext ? myBarPage.getNumber() + 1 : null;
+        LocalDateTime nextKeptAt = null;
+        Long nextId = null;
+        if (hasNext && !rows.isEmpty()) {
+            MyBar last = rows.get(rows.size() - 1);
+            nextKeptAt = last.getKeptAt();
+            nextId = last.getId();
+        }
 
-        return new MyBarListResponseDto(items, hasNext, nextPage);
+        return new MyBarListResponseDto(items, hasNext, nextKeptAt, nextId);
     }
 
     @Transactional
@@ -75,3 +96,4 @@ public void unkeep(Long userId, Long cocktailId) {
         myBarRepository.softDeleteByUserAndCocktail(userId, cocktailId);
     }
 }
+