[FEAT] 팔로워 목록 조회 API 개발

src/main/java/team/wego/wegobackend/user/application/FollowService.java

@@ -1,18 +1,18 @@
 package team.wego.wegobackend.user.application;
 
+import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
-import team.wego.wegobackend.notification.application.SseEmitterService;
-import team.wego.wegobackend.notification.application.dto.NotificationType;
-import team.wego.wegobackend.notification.application.dto.response.NotificationResponse;
-import team.wego.wegobackend.notification.domain.Notification;
-import team.wego.wegobackend.notification.repository.NotificationRepository;
 import team.wego.wegobackend.user.application.dto.response.FollowListResponse;
 import team.wego.wegobackend.user.application.dto.response.FollowResponse;
+import team.wego.wegobackend.user.application.dto.response.FollowerListResponse;
+import team.wego.wegobackend.user.application.dto.response.WrapperFollowerResponse;
 import team.wego.wegobackend.user.application.event.FollowEvent;
 import team.wego.wegobackend.user.domain.Follow;
 import team.wego.wegobackend.user.domain.User;
@@ -34,10 +34,6 @@ public class FollowService {
 
     private final UserRepository userRepository;
 
-    private final NotificationRepository notificationRepository;
-
-    private final SseEmitterService sseEmitterService;
-
     private final ApplicationEventPublisher eventPublisher;
 
     public void follow(String followNickname, Long followerId) {
@@ -101,4 +97,30 @@ public FollowListResponse followList(Long userId, Long cursor, Integer size) {
 
         return new FollowListResponse(list, nextCursor);
     }
+
+    @Transactional(readOnly = true)
+    public FollowerListResponse followerList(Long userId, Long cursor, Integer size) {
+
+        if (!userRepository.existsById(userId)) {
+            throw new UserNotFoundException();
+        }
+
+        List<FollowResponse> list = followRepository.findFollowerList(userId, cursor, size);
+
+        // 맞팔로우 여부 조회: 내가 팔로우한 사람들의 ID 조회
+        Set<Long> followingUserIds = followRepository.findFolloweeIdsByFollowerId(userId);
+
+        List<WrapperFollowerResponse> result = new ArrayList<>();
+
+        for(FollowResponse follower : list) {
+            boolean isFollow = followingUserIds.contains(follower.getUserId());
+                follower.getUserId(), follower.getNickname(), isFollow);
+            WrapperFollowerResponse response = new WrapperFollowerResponse(follower, isFollow);
+            result.add(response);
+        }
+
+        Long nextCursor = list.isEmpty() ? null : list.getLast().getFollowId();
+
+        return new FollowerListResponse(result, nextCursor);
+    }
 }

src/main/java/team/wego/wegobackend/user/application/dto/response/FollowerListResponse.java

@@ -0,0 +1,7 @@
+package team.wego.wegobackend.user.application.dto.response;
+
+import java.util.List;
+
+public record FollowerListResponse(List<WrapperFollowerResponse> items, Long nextCursor) {
+
+}

src/main/java/team/wego/wegobackend/user/application/dto/response/WrapperFollowerResponse.java

@@ -0,0 +1,24 @@
+package team.wego.wegobackend.user.application.dto.response;
+
+import lombok.Getter;
+
+@Getter
+public class WrapperFollowerResponse {
+
+    private final Long followId;    //cursor
+    private final Long userId;
+    private final String profileImage;
+    private final String nickname;
+    private final String profileMessage;
+    private final boolean isFollow;
+
+    public WrapperFollowerResponse(FollowResponse followResponse, boolean isFollow) {
+        this.followId = followResponse.getFollowId();
+        this.userId = followResponse.getUserId();
+        this.profileImage = followResponse.getProfileImage();
+        this.nickname = followResponse.getNickname();
+        this.profileMessage = followResponse.getProfileMessage();
+        this.isFollow = isFollow;
+    }
+
+}

src/main/java/team/wego/wegobackend/user/presentation/UserController.java

@@ -29,6 +29,7 @@
 import team.wego.wegobackend.user.application.dto.request.ProfileUpdateRequest;
 import team.wego.wegobackend.user.application.dto.response.AvailabilityResponse;
 import team.wego.wegobackend.user.application.dto.response.FollowListResponse;
+import team.wego.wegobackend.user.application.dto.response.FollowerListResponse;
 import team.wego.wegobackend.user.application.dto.response.UserInfoResponse;
 
 @Slf4j
@@ -174,6 +175,23 @@ public ResponseEntity<ApiResponse<FollowListResponse>> followList(
             .body(ApiResponse.success(200, response));
     }
 
+    /**
+     * 팔로워 리스트 조회
+     */
+    @GetMapping("/{userId}/follower")
+    public ResponseEntity<ApiResponse<FollowerListResponse>> followerList(
+        @PathVariable Long userId, //다른 유저 조회를 위한 파라메터
+        @RequestParam(required = false) Long cursor,
+        @RequestParam(defaultValue = "20") @Min(1) @Max(100) Integer size
+    ) {
+
+        FollowerListResponse response = followService.followerList(userId, cursor, size);
+
+        return ResponseEntity
+            .status(HttpStatus.OK)
+            .body(ApiResponse.success(200, response));
+    }
+
     /**
      * 이메일 중복검사
      */

src/main/java/team/wego/wegobackend/user/repository/FollowRepository.java

@@ -1,7 +1,10 @@
 package team.wego.wegobackend.user.repository;
 
 import java.util.Optional;
+import java.util.Set;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 import team.wego.wegobackend.user.domain.Follow;
 
 public interface FollowRepository extends JpaRepository<Follow, Long>, FollowRepositoryCustom {
@@ -12,4 +15,7 @@ public interface FollowRepository extends JpaRepository<Follow, Long>, FollowRep
     void deleteByFollowerId(Long userId);
 
     void deleteByFolloweeId(Long userId);
+
+    @Query("SELECT f.followee.id FROM Follow f WHERE f.follower.id = :followerId")
+    Set<Long> findFolloweeIdsByFollowerId(@Param("followerId") Long followerId);
 }

src/main/java/team/wego/wegobackend/user/repository/FollowRepositoryCustom.java

@@ -13,6 +13,12 @@ List<FollowResponse> findFollowingList(
             int size
     );
 
+    List<FollowResponse> findFollowerList(
+        Long followerId,
+        Long cursorFollowId,
+        int size
+    );
+
     List<FollowerNotifyRow> findFollowersForNotify(Long followeeId, Long cursorFollowId, int size);
 
 }

src/main/java/team/wego/wegobackend/user/repository/FollowRepositoryImpl.java

@@ -19,66 +19,95 @@ public class FollowRepositoryImpl implements FollowRepositoryCustom {
 
     @Override
     public List<FollowResponse> findFollowingList(
-            Long followerId,
-            Long cursorFollowId,
-            int size
+        Long followerId,
+        Long cursorFollowId,
+        int size
     ) {
 
         QFollow follow = QFollow.follow;
         QUser user = QUser.user;
 
         return jpaQueryFactory
-                .select(new QFollowResponse(
-                        follow.id,
-                        user.id,
-                        user.profileImage,
-                        user.nickName,
-                        user.profileMessage
-                ))
-                .from(follow)
-                .join(follow.followee, user)
-                .where(
-                        follow.follower.id.eq(followerId),
-                        itCursor(cursorFollowId)
-                )
-                .orderBy(follow.id.desc())  //최신 팔로우 순
-                .limit(size)
-                .fetch();
+            .select(new QFollowResponse(
+                follow.id,
+                user.id,
+                user.profileImage,
+                user.nickName,
+                user.profileMessage
+            ))
+            .from(follow)
+            .join(follow.followee, user)
+            .where(
+                follow.follower.id.eq(followerId),
+                itCursor(cursorFollowId)
+            )
+            .orderBy(follow.id.desc())  //최신 팔로우 순
+            .limit(size)
+            .fetch();
+    }
+
+    @Override
+    public List<FollowResponse> findFollowerList(
+        Long followId,
+        Long cursorFollowId,
+        int size
+    ) {
+
+        QFollow follow = QFollow.follow;
+        QUser user = QUser.user;
+
+        return jpaQueryFactory
+            .select(new QFollowResponse(
+                follow.id,
+                user.id,
+                user.profileImage,
+                user.nickName,
+                user.profileMessage
+            ))
+            .from(follow)
+            .join(follow.follower, user)
+            .where(
+                follow.followee.id.eq(followId),
+                itCursor(cursorFollowId)
+            )
+            .orderBy(follow.id.desc())  //최신 팔로우 순
+            .limit(size)
+            .fetch();
     }
 
     private BooleanExpression itCursor(Long cursorFollowId) {
         return cursorFollowId == null
-                ? null
-                : QFollow.follow.id.lt(cursorFollowId);
+            ? null
+            : QFollow.follow.id.lt(cursorFollowId);
     }
 
     @Override
     public List<FollowerNotifyRow> findFollowersForNotify(
-            Long followeeId,
-            Long cursorFollowId,
-            int size
+        Long followeeId,
+        Long cursorFollowId,
+        int size
     ) {
         QFollow follow = QFollow.follow;
         QUser user = QUser.user;
 
         return jpaQueryFactory
-                .select(Projections.constructor(
-                        FollowerNotifyRow.class,
-                        follow.id,
-                        user.id,
-                        user.nickName,
-                        user.profileImage
-                ))
-                .from(follow)
-                .join(follow.follower, user)
-                .where(
-                        follow.followee.id.eq(followeeId),
-                        cursorFollowId == null ? null : follow.id.lt(cursorFollowId),
-                        user.notificationEnabled.isTrue(),
-                        user.deleted.isFalse()
-                )
-                .orderBy(follow.id.desc())
-                .limit(size)
-                .fetch();
+            .select(Projections.constructor(
+                FollowerNotifyRow.class,
+                follow.id,
+                user.id,
+                user.nickName,
+                user.profileImage
+            ))
+            .from(follow)
+            .join(follow.follower, user)
+            .where(
+                follow.followee.id.eq(followeeId),
+                cursorFollowId == null ? null : follow.id.lt(cursorFollowId),
+                user.notificationEnabled.isTrue(),
+                user.deleted.isFalse()
+            )
+            .orderBy(follow.id.desc())
+            .limit(size)
+            .fetch();
     }
 }

src/test/http/user/user-api.http

@@ -68,7 +68,7 @@ Content-Type: application/json
 }
 
 ### 팔로우 요청
-POST http://localhost:8080/api/v1/users/follow?followNickname=user0
+POST http://localhost:8080/api/v1/users/follow?followNickname=ttest
 Authorization: Bearer {{accessToken}}
 
 ### 팔로우 취소
@@ -91,6 +91,20 @@ GET http://localhost:8080/api/v1/users/1/follow?size=10
 ### 팔로우 리스트 조회 (cursor)
 GET http://localhost:8080/api/v1/users/1/follow?cursor={{nextCursor}}&size=10
 
+> {%
+  client.global.set("nextCursor", response.body.data.nextCursor);
+%}
+
+### 팔로워 리스트 조회 (초기값)
+GET http://localhost:8080/api/v1/users/102/follower?size=10
+
+> {%
+  client.global.set("nextCursor", response.body.data.nextCursor);
+%}
+
+### 팔로워 리스트 조회 (cursor)
+GET http://localhost:8080/api/v1/users/1/follower?cursor={{nextCursor}}&size=10
+
 > {%
   client.global.set("nextCursor", response.body.data.nextCursor);
 %}