Merge pull request #122 from Dev-Race/refactor/#121

[#121] Refactor: Fetch Join 추가 리팩토링 및 성능 개선

src/main/java/com/sajang/devracebackend/controller/RoomController.java

@@ -2,10 +2,9 @@
 
 import com.sajang.devracebackend.config.RabbitConfig;
 import com.sajang.devracebackend.dto.problem.ProblemSaveRequestDto;
-import com.sajang.devracebackend.dto.room.RoomSaveResponseDto;
+import com.sajang.devracebackend.dto.room.RoomResponseDto;
 import com.sajang.devracebackend.dto.room.RoomWaitRequestDto;
 import com.sajang.devracebackend.dto.room.RoomWaitResponseDto;
-import com.sajang.devracebackend.dto.userroom.CodeRoomResponseDto;
 import com.sajang.devracebackend.dto.userroom.UserPassRequestDto;
 import com.sajang.devracebackend.dto.userroom.RoomCheckAccessResponseDto;
 import com.sajang.devracebackend.dto.room.RoomCheckStateResponseDto;
@@ -18,10 +17,6 @@
 import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.RequiredArgsConstructor;
 import org.springframework.amqp.rabbit.core.RabbitTemplate;
-import org.springframework.data.domain.Page;
-import org.springframework.data.domain.Pageable;
-import org.springframework.data.domain.Sort;
-import org.springframework.data.web.PageableDefault;
 import org.springframework.http.ResponseEntity;
 import org.springframework.messaging.handler.annotation.MessageMapping;
 import org.springframework.messaging.handler.annotation.Payload;
@@ -41,9 +36,16 @@ public class RoomController {
 
     @PostMapping("/rooms")
     @Operation(summary = "방생성 Page - 방 생성 [jwt O]")
-    public ResponseEntity<ResponseData<RoomSaveResponseDto>> createRoom(@RequestBody ProblemSaveRequestDto problemSaveRequestDto) throws IOException {
-        RoomSaveResponseDto roomSaveResponseDto = roomService.createRoom(problemSaveRequestDto);
-        return ResponseData.toResponseEntity(ResponseCode.CREATED_ROOM, roomSaveResponseDto);
+    public ResponseEntity<ResponseData<RoomResponseDto>> createRoom(@RequestBody ProblemSaveRequestDto problemSaveRequestDto) throws IOException {
+        RoomResponseDto roomResponseDto = roomService.createRoom(problemSaveRequestDto);
+        return ResponseData.toResponseEntity(ResponseCode.CREATED_ROOM, roomResponseDto);
+    }
+
+    @GetMapping("/rooms")
+    @Operation(summary = "초대링크 방 조회 [jwt O]", description = "URI : /rooms?link={방링크 string}")
+    public ResponseEntity<ResponseData<RoomResponseDto>> findRoomByLink(@RequestParam(value = "link", required = true) String link) {
+        RoomResponseDto roomResponseDto = roomService.findRoomByLink(link);
+        return ResponseData.toResponseEntity(ResponseCode.READ_ROOM, roomResponseDto);
     }
 
     @GetMapping("/rooms/{roomId}")
@@ -68,7 +70,7 @@ public ResponseEntity<ResponseData<RoomCheckStateResponseDto>> checkState(@PathV
     }
 
     @PostMapping("/rooms/{roomId}")  // 의미상 PUT보단 POST가 더 적합하다고 판단했음.
-    @Operation(summary = "문제풀이 Page - 문제풀이 실패 및 성공 [jwt O]", description = "isRetry==0 : 첫풀이 경우 / isRetry==1 : 재풀이 경우")
+    @Operation(summary = "문제풀이 Page - 문제풀이 성공 및 실패/퇴장 [jwt O]", description = "isRetry==0 : 첫풀이 경우 / isRetry==1 : 재풀이 경우")
     public ResponseEntity<ResponseData> passSolvingProblem(
             @PathVariable(value = "roomId") Long roomId,
             @RequestBody UserPassRequestDto userPassRequestDto) {
@@ -84,24 +86,6 @@ public ResponseEntity<ResponseData> userStopWaitRoom(@PathVariable(value = "room
         return ResponseData.toResponseEntity(ResponseCode.UPDATE_ROOM);
     }
 
-    @GetMapping("/rooms")
-    @Operation(summary = "내 코드방 목록 조회/정렬/검색 [jwt O]",
-            description = """
-                - 전체 정렬 URI : /rooms?page={페이지번호 int}
-                - 성공or실패 정렬 URI : /rooms?isPass={풀이성공여부 int}&page={페이지번호 int}
-                - 문제번호 검색 URI : /rooms?number={문제번호 int}&page={페이지번호 int}
-                - 초대링크 탐색 URI : /rooms?link={방링크 string}  \nsize, sort 필요X (기본값 : page=0 & size=9 & sort=createdTime,desc)
-                """)
-    public ResponseEntity<ResponseData<Page<CodeRoomResponseDto>>> findCodeRoom(
-            @RequestParam(value = "isPass", required = false) Integer isPass,
-            @RequestParam(value = "number", required = false) Integer number,
-            @RequestParam(value = "link", required = false) String link,
-            @PageableDefault(page=0, size=9, sort="createdTime", direction = Sort.Direction.DESC) Pageable pageable) {
-
-        Page<CodeRoomResponseDto> codeRoomResponseDtoPage = userRoomService.findCodeRoom(isPass, number, link, pageable);
-        return ResponseData.toResponseEntity(ResponseCode.READ_USERROOM, codeRoomResponseDtoPage);
-    }
-
     @MessageMapping("wait.enter")  // 웹소켓 메시지 처리 (백엔드로 '/pub/wait.enter'를 호출시 이 브로커에서 처리)
     public void userWaitRoom(@Payload RoomWaitRequestDto roomWaitRequestDto) {
         // '/exchange/wait.exchange/waitingroom.{roomId}' 구독되어있는 프론트엔드에게 메세지 전달.

src/main/java/com/sajang/devracebackend/controller/UserController.java

@@ -4,18 +4,21 @@
 import com.sajang.devracebackend.dto.user.UserResponseDto;
 import com.sajang.devracebackend.dto.user.UserSolvedResponseDto;
 import com.sajang.devracebackend.dto.user.UserUpdateRequestDto;
+import com.sajang.devracebackend.dto.userroom.CodeRoomResponseDto;
 import com.sajang.devracebackend.response.ResponseCode;
 import com.sajang.devracebackend.response.ResponseData;
+import com.sajang.devracebackend.service.UserRoomService;
 import com.sajang.devracebackend.service.UserService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.web.PageableDefault;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.PutMapping;
-import org.springframework.web.bind.annotation.RequestPart;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.bind.annotation.*;
 import org.springframework.web.multipart.MultipartFile;
 
 import java.io.IOException;
@@ -26,6 +29,7 @@
 public class UserController {
 
     private final UserService userService;
+    private final UserRoomService userRoomService;
 
 
     @GetMapping("/users")
@@ -50,17 +54,33 @@ public ResponseEntity<ResponseData> updateUserProfile(
         return ResponseData.toResponseEntity(ResponseCode.UPDATE_USER);
     }
 
-    @GetMapping("/users/solved-count")
-    @Operation(summary = "백준 solvedCount값 조회 [jwt O]")
-    public ResponseEntity<ResponseData<UserSolvedResponseDto>> checkUserSolvedCount() {
-        UserSolvedResponseDto userSolvedResponseDto = userService.checkUserSolvedCount();
-        return ResponseData.toResponseEntity(ResponseCode.READ_SOLVEDCOUNT, userSolvedResponseDto);
+    @GetMapping("/users/rooms")
+    @Operation(summary = "코드방 목록 조회/정렬/검색 [jwt O]",
+            description = """
+                - 전체 정렬 URI : /users/rooms?page={페이지번호 int}
+                - 성공or실패 정렬 URI : /users/rooms?isPass={풀이성공여부 int}&page={페이지번호 int}
+                - 문제번호 검색 URI : /users/rooms?number={문제번호 int}&page={페이지번호 int}  \nsize, sort 필요X (기본값 : size=9 & sort=createdTime,desc)
+                """)
+    public ResponseEntity<ResponseData<Page<CodeRoomResponseDto>>> findCodeRooms(
+            @RequestParam(value = "isPass", required = false) Integer isPass,
+            @RequestParam(value = "number", required = false) Integer number,
+            @PageableDefault(size=9, sort="createdTime", direction = Sort.Direction.DESC) Pageable pageable) {
+
+        Page<CodeRoomResponseDto> codeRoomResponseDtoPage = userRoomService.findCodeRooms(isPass, number, pageable);
+        return ResponseData.toResponseEntity(ResponseCode.READ_USERROOM, codeRoomResponseDtoPage);
     }
 
-    @GetMapping("/users/room-check")
+    @GetMapping("/users/rooms-check")
     @Operation(summary = "메인 Page - 참여중인 방 여부 검사 [jwt O]", description = "roomId == Long or null")
     public ResponseEntity<ResponseData<UserCheckRoomResponseDto>> checkCurrentRoom() {
         UserCheckRoomResponseDto userCheckRoomResponseDto = userService.checkCurrentRoom();
         return ResponseData.toResponseEntity(ResponseCode.READ_ROOM, userCheckRoomResponseDto);
     }
+
+    @GetMapping("/users/solved-count")
+    @Operation(summary = "백준 solvedCount값 조회 [jwt O]")
+    public ResponseEntity<ResponseData<UserSolvedResponseDto>> checkUserSolvedCount() {
+        UserSolvedResponseDto userSolvedResponseDto = userService.checkUserSolvedCount();
+        return ResponseData.toResponseEntity(ResponseCode.READ_SOLVEDCOUNT, userSolvedResponseDto);
+    }
 }

src/main/java/com/sajang/devracebackend/domain/Room.java

@@ -36,14 +36,14 @@ public class Room extends BaseEntity implements Serializable{
     @Column(name = "room_state")
     private RoomState roomState;
 
+    // Room 조회시 Room.problem N+1 문제 해결 ==> Eager 조회 : '@EntityGraph 적용 메소드 활용', Lazy 조회 : '기본 지연로딩 용도'
     @ManyToOne(fetch = FetchType.LAZY)  // Room-Problem 단방향매핑
     @JoinColumn(name = "problem_id")
     private Problem problem;
 
-    // 밑처럼 과도한 N+1 문제를 유발할 서비스 로직이 없을뿐더러 활용 빈도수도 낮기때문에, fetch join이나 @EntityGraph를 사용하지 않은채로 지연 로딩을 유지하도록 했음.
-    // 과도한 N+1 예시: Rooms를 JPA의 findAll()로 호출하고, 각 Room을 순회하며 room.getUserRoomList.get내부속성()으로 접근하는 경우.
+    // Room 조회시 Room.userRoomList N+1 문제 해결 ==> Eager 조회 : '방의 입장인원 전원 퇴장여부 확인 용도', Lazy 조회 : '기본 지연로딩 용도'
     @OneToMany(mappedBy = "room")  // Room-UserRoom 양방향매핑 (읽기 전용 필드)
-    private List<UserRoom> userRoomList = new ArrayList<>();  // '방의 입장인원 전원 퇴장여부 확인 용도'에 활용.
+    private List<UserRoom> userRoomList = new ArrayList<>();
 
 
     @Builder(builderClassName = "RoomSaveBuilder", builderMethodName = "RoomSaveBuilder")

src/main/java/com/sajang/devracebackend/domain/User.java

@@ -47,10 +47,9 @@ public class User extends BaseEntity implements Serializable {
     @Column(name = "refresh_token")
     private String refreshToken;
 
-    // 밑처럼 과도한 N+1 문제를 유발할 서비스 로직이 없을뿐더러 활용 빈도수도 낮기때문에, fetch join이나 @EntityGraph를 사용하지 않은채로 지연 로딩을 유지하도록 했음.
-    // 과도한 N+1 예시: Users를 JPA의 findAll()로 호출하고, 각 User를 순회하며 user.getUserRoomList.get내부속성()으로 접근하는 경우.
+    // User 조회시 User.userRoomList N+1 문제 해결 ==> Eager 조회 : '사용자의 참여중인 방 찾는 용도', Lazy 조회 : '기본 지연로딩 용도 & 회원탈퇴 용도'
     @OneToMany(mappedBy = "user")  // User-UserRoom 양방향매핑 (읽기 전용 필드)
-    private List<UserRoom> userRoomList = new ArrayList<>();  // '사용자의 참여중인 방 찾는 용도 & 회원탈퇴 용도'에 활용.
+    private List<UserRoom> userRoomList = new ArrayList<>();
 
 
     @Builder(builderClassName = "UserSaveBuilder", builderMethodName = "UserSaveBuilder")

src/main/java/com/sajang/devracebackend/domain/mapping/UserRoom.java

@@ -39,11 +39,13 @@ public class UserRoom extends BaseEntity implements Serializable {
     @Column(name = "leave_time")
     private LocalDateTime leaveTime;  // 퇴장 시각 (반면, createdTime = 입장 시각)
 
+    // Eager 조회의 용도가 적어, 기본 Lazy 조회로만 사용함.
     @ManyToOne(fetch = FetchType.LAZY)  // User-UserRoom 양방향매핑
     @JoinColumn(name = "user_id")
     private User user;
 
-    @ManyToOne(fetch = FetchType.LAZY)  // Room-UserRoom 양방향매핑 (default로 Lazy를 적용하되, Eager가 필요할경우 따로 메소드를 만들어 사용함.)
+    // UserRoom 조회시 UserRoom.room N+1 문제 해결 ==> Eager 조회 : '@EntityGraph 적용 메소드 활용', Lazy 조회 : '기본 지연로딩 용도'
+    @ManyToOne(fetch = FetchType.LAZY)  // Room-UserRoom 양방향매핑
     @JoinColumn(name = "room_id")
     private Room room;
 

src/main/java/com/sajang/devracebackend/dto/room/RoomSaveResponseDto.java → src/main/java/com/sajang/devracebackend/dto/room/RoomResponseDto.java

@@ -9,7 +9,7 @@
 @Getter
 @NoArgsConstructor
 @AllArgsConstructor
-public class RoomSaveResponseDto {
+public class RoomResponseDto {
 
     private Long roomId;
 }

src/main/java/com/sajang/devracebackend/repository/RoomRepository.java

@@ -3,5 +3,8 @@
 import com.sajang.devracebackend.domain.Room;
 import org.springframework.data.jpa.repository.JpaRepository;
 
+import java.util.Optional;
+
 public interface RoomRepository extends JpaRepository<Room, Long> {
+    Optional<Room> findByLink(String link);
 }

src/main/java/com/sajang/devracebackend/repository/UserRepository.java

@@ -3,11 +3,20 @@
 import com.sajang.devracebackend.domain.User;
 import com.sajang.devracebackend.domain.enums.SocialType;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
 import java.util.List;
 import java.util.Optional;
 
 public interface UserRepository extends JpaRepository<User, Long> {
+    // '@EntityGraph' 또는 'Fetch Join'을 통해 User 조회시, 내부의 Lazy 로딩으로 선언된 속성 또한 Eager로 한번에 조회.
+    // ==> N+1 문제 해결 (간단한 로직은 '@EntityGraph'로, 복잡한 로직이거나 기존 JPA 메소드와의 네이밍 충돌을 방지하고자하는 경우는 'Fetch Join'을 활용.)
+
+    // - Eager 조회 : 'User + User.userRoomList'
+    @Query("SELECT u FROM User u JOIN FETCH u.userRoomList WHERE u.id = :userId")
+    Optional<User> findByIdWithEagerUserRoomList(@Param("userId") Long userId);  // 기존의 JPA findById() 메소드를 @Override 하지않고 유지하기위해, @Query로 새로운 메소드 네이밍을 지어주었음. -> '@EntityGraph' 말고 'Fetch Join' 사용.
+
     Optional<User> findBySocialTypeAndSocialId(SocialType socialType, String socialId);  // '소셜 타입, 식별자'로 해당 회원을 찾기 위한 메소드 (차후 추가정보 입력 회원가입 가능)
     boolean existsByBojId(String bojId);
     List<User> findByIdIn(List<Long> userIdList);

src/main/java/com/sajang/devracebackend/repository/UserRoomRepository.java

@@ -7,21 +7,36 @@
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
 import java.util.Optional;
 
 public interface UserRoomRepository extends JpaRepository<UserRoom, Long> {
+    // '@EntityGraph' 또는 'Fetch Join'을 통해 UserRoom 조회시, 내부의 Lazy 로딩으로 선언된 속성 또한 Eager로 한번에 조회.
+    // ==> N+1 문제 해결 (간단한 로직은 '@EntityGraph'로, 복잡한 로직이거나 기존 JPA 메소드와의 네이밍 충돌을 방지하고자하는 경우는 'Fetch Join'을 활용.)
 
-    // 서비스 로직에 UserRoom과 내부의 Room 정보를 모두 조회하여 사용하는 경우가 많았기에, 이를 적용하였음.
-    // @EntityGraph를 통해 UserRoom 조회시, 내부의 Lazy 로딩으로 선언된 Room 또한 Eager로 한번에 조회하여, N+1 문제를 해결.
-    // ==> Eager 조회 : 'UserRoom + 내부 Room', Lazy 조회 : '내부 User'
-    @EntityGraph(attributePaths = {"room"})
-    Optional<UserRoom> findByUser_IdAndRoom_Id(Long userId, Long roomId);
+    // - Eager 조회 : 'UserRoom + UserRoom.room', Lazy 조회 : 'UserRoom.user'
+    @EntityGraph(attributePaths = {"room"})  // 반환값이 List가 아닌 고유한 하나의 값이기에, @EntityGraph임에도 DISTINCT 없이 작성했음.
+    Optional<UserRoom> findByUser_IdAndRoom_Id(Long userId, Long roomId);  // 이는 @Query가 아니므로, JPA네이밍 규칙에 영향을 받음.
+
+    // - Eager 조회 : 'UserRoom + UserRoom.room + UserRoom.room.userRoomList', Lazy 조회 : 'UserRoom.user'
+    @Query("SELECT ur FROM UserRoom ur JOIN FETCH ur.room r JOIN FETCH r.userRoomList WHERE ur.user.id = :userId AND ur.room.id = :roomId")
+    Optional<UserRoom> findByUser_IdAndRoom_IdWithUserRoomList(@Param("userId") Long userId, @Param("roomId") Long roomId);  // @Query 이므로, With문처럼 JPA네이밍 규칙을 지키지않아도됨.
+
+    // - Eager 조회 : 'UserRoom + UserRoom.room + UserRoom.room.problem', Lazy 조회 : 'UserRoom.user'
+    @Query("SELECT ur FROM UserRoom ur JOIN FETCH ur.room r JOIN FETCH r.problem WHERE ur.user.id = :userId AND ur.room.id = :roomId")
+    Optional<UserRoom> findByUser_IdAndRoom_IdWithProblem(@Param("userId") Long userId, @Param("roomId") Long roomId);  // @Query 이므로, With문처럼 JPA네이밍 규칙을 지키지않아도됨.
 
     boolean existsByUserAndRoom(User user, Room room);
 
-    Page<UserRoom> findAllByIsLeaveAndUser_Id(Integer isLeave, Long userId, Pageable pageable);
-    Page<UserRoom> findAllByIsLeaveAndIsPass(Integer isLeave, Integer isPass, Pageable pageable);
-    Page<UserRoom> findAllByIsLeaveAndRoom_Problem_Number(Integer isLeave, Integer number, Pageable pageable);
-    Page<UserRoom> findAllByRoom_Link(String link, Pageable pageable);
+    // 밑의 3가지 메소드 모두, 페이징에서 OneToMany 속성을 Eager 조회시키지 않을것이기에, '중복 제거 처리' 및 '배치 사이즈 선언'을 하지 않았음.
+    @EntityGraph(attributePaths = {"room", "room.problem"})
+    Page<UserRoom> findAllByUser_IdAndIsLeave(Long userId, Integer isLeave, Pageable pageable);
+
+    @EntityGraph(attributePaths = {"room", "room.problem"})
+    Page<UserRoom> findAllByUser_IdAndIsLeaveAndIsPass(Long userId, Integer isLeave, Integer isPass, Pageable pageable);
+
+    @EntityGraph(attributePaths = {"room", "room.problem"})
+    Page<UserRoom> findAllByUser_IdAndIsLeaveAndRoom_Problem_Number(Long userId, Integer isLeave, Integer number, Pageable pageable);
 }

src/main/java/com/sajang/devracebackend/service/RoomService.java

@@ -3,12 +3,13 @@
 import com.sajang.devracebackend.domain.Room;
 import com.sajang.devracebackend.dto.problem.ProblemSaveRequestDto;
 import com.sajang.devracebackend.dto.room.RoomCheckStateResponseDto;
-import com.sajang.devracebackend.dto.room.RoomSaveResponseDto;
+import com.sajang.devracebackend.dto.room.RoomResponseDto;
 
 import java.io.IOException;
 
 public interface RoomService {
     Room findRoom(Long roomId);
-    RoomSaveResponseDto createRoom(ProblemSaveRequestDto problemSaveRequestDto) throws IOException;
+    RoomResponseDto findRoomByLink(String link);
+    RoomResponseDto createRoom(ProblemSaveRequestDto problemSaveRequestDto) throws IOException;
     RoomCheckStateResponseDto checkState(Long roomId);
 }

src/main/java/com/sajang/devracebackend/service/UserRoomService.java

@@ -11,12 +11,12 @@
 import org.springframework.data.domain.Pageable;
 
 public interface UserRoomService {
-    UserRoom findUserRoom(Long userId, Long roomId);  // Eager 조회 : 'UserRoom + 내부 Room', Lazy 조회 : '내부 User'
+    UserRoom findUserRoomWithEagerRoom(Long userId, Long roomId, boolean isIncludeUserRoomList, boolean isIncludeProblem);
     RoomWaitResponseDto userWaitRoom(RoomWaitRequestDto roomWaitRequestDto);
     void usersEnterRoom(Long roomId);
     void userStopWaitRoom(Long roomId);
     SolvingPageResponseDto loadSolvingPage(Long roomId);
     RoomCheckAccessResponseDto checkAccess(Long roomId);
     void passSolvingProblem(Long roomId, UserPassRequestDto userPassRequestDto);
-    Page<CodeRoomResponseDto> findCodeRoom(Integer isPass, Integer number, String link, Pageable pageable);
+    Page<CodeRoomResponseDto> findCodeRooms(Integer isPass, Integer number, Pageable pageable);
 }

src/main/java/com/sajang/devracebackend/service/UserService.java

@@ -13,7 +13,7 @@
 public interface UserService {
     User findUser(Long userId);
     User findLoginUser();
-    <T> List<T> findUsersOriginal(List<Long> userIdList, Boolean isDto);
+    <T> List<T> findUsersOriginal(List<Long> userIdList, boolean isDto);
     UserResponseDto findUserProfile();
     void updateUserProfile(MultipartFile imageFile, UserUpdateRequestDto userUpdateRequestDto) throws IOException;
     UserSolvedResponseDto checkUserSolvedCount();