[✨feat/#185]: 공고 페이징 및 서비스 로직 개선

- 공고 조회 API에 페이징 기능 추가
  - Pageable을 활용한 페이징 처리 구현
  - `@PageableDefault`를 통해 기본 페이지 크기 설정
- DTO 수정
  - HomeAnnouncementsResponseDto에 페이징 관련 필드 추가 (`totalPages`, `hasNext`)
- Repository 수정
  - 페이징 처리된 공고 데이터를 반환하도록 쿼리 수정
  - `Page<Tuple>`를 활용한 페이징 로직 구현
- Service 로직 리팩토링
  - 공통 메서드 분리 (`getUserById`, `createEmptyResponse` 등)
  - Color 값 및 스크랩 여부 처리 메서드 분리 (`isScrapped`, `determineColorValue`)
- Swagger 수정
  - API 문서에 페이징 파라미터 반영

src/main/java/org/terning/terningserver/controller/HomeController.java

@@ -1,6 +1,8 @@
 package org.terning.terningserver.controller;
 
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.web.PageableDefault;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.web.bind.annotation.*;
@@ -26,13 +28,14 @@ public class HomeController implements HomeSwagger {
     @GetMapping("/home")
     public ResponseEntity<SuccessResponse<HomeAnnouncementsResponseDto>> getAnnouncements(
             @AuthenticationPrincipal Long userId,
-            @RequestParam(value = "sortBy", required = false, defaultValue = "deadlineSoon") String sortBy
-    ){
-        HomeAnnouncementsResponseDto announcements = homeService.getAnnouncements(userId, sortBy);
+            @RequestParam(value = "sortBy", required = false, defaultValue = "deadlineSoon") String sortBy,
+            @PageableDefault(size = 10) Pageable pageable) {
+        HomeAnnouncementsResponseDto announcements = homeService.getAnnouncements(userId, sortBy, pageable);
 
         return ResponseEntity.ok(SuccessResponse.of(SUCCESS_GET_ANNOUNCEMENTS, announcements));
     }
 
+
     @GetMapping("/home/upcoming")
     public ResponseEntity<SuccessResponse<List<UpcomingScrapResponseDto>>> getUpcomingScraps(
             @AuthenticationPrincipal Long userId

src/main/java/org/terning/terningserver/controller/swagger/HomeSwagger.java

@@ -2,6 +2,7 @@
 
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
+import org.springframework.data.domain.Pageable;
 import org.springframework.http.ResponseEntity;
 import org.terning.terningserver.dto.user.response.HomeAnnouncementsResponseDto;
 import org.terning.terningserver.dto.user.response.UpcomingScrapResponseDto;
@@ -15,7 +16,8 @@ public interface HomeSwagger {
     @Operation(summary = "홈화면 > 나에게 딱맞는 인턴 공고 조회", description = "특정 사용자에 필터링 조건에 맞는 인턴 공고 정보를 조회하는 API")
     ResponseEntity<SuccessResponse<HomeAnnouncementsResponseDto>> getAnnouncements(
             Long userId,
-            String sortBy
+            String sortBy,
+            Pageable pageable
     );
 
     @Operation(summary = "홈화면 > 곧 마감인 스크랩 공고 조회", description = "곧 마감인 스크랩 공고를 조회하는 API")

src/main/java/org/terning/terningserver/dto/user/response/HomeAnnouncementsResponseDto.java

@@ -6,12 +6,20 @@
 
 @Builder
 public record HomeAnnouncementsResponseDto(
-        int totalCount, // 필터링 된 공고 총 개수
+        int totalPages,
+        long totalCount,
+        boolean hasNext,
         List<HomeResponseDto> result
 ) {
-    public static HomeAnnouncementsResponseDto of(final int totalCount, final List<HomeResponseDto> announcements){
+    public static HomeAnnouncementsResponseDto of(
+            final int totalPages,
+            final long totalCount,
+            final boolean hasNext,
+            final List<HomeResponseDto> announcements) {
         return HomeAnnouncementsResponseDto.builder()
+                .totalPages(totalPages)
                 .totalCount(totalCount)
+                .hasNext(hasNext)
                 .result(announcements)
                 .build();
     }

src/main/java/org/terning/terningserver/repository/internship_announcement/InternshipRepositoryCustom.java

@@ -15,6 +15,5 @@ public interface InternshipRepositoryCustom {
 
     Page<InternshipAnnouncement> searchInternshipAnnouncement(String keyword, String sortBy, Pageable pageable);
 
-    List<Tuple> findFilteredInternshipsWithScrapInfo(User user, String sortBy);
-
+    Page<Tuple> findFilteredInternshipsWithScrapInfo(User user, String sortBy, Pageable pageable);
 }

src/main/java/org/terning/terningserver/repository/internship_announcement/InternshipRepositoryImpl.java

@@ -110,9 +110,9 @@ private OrderSpecifier createOrderSpecifier(String sortBy) {
     }
 
     @Override
-    public List<Tuple> findFilteredInternshipsWithScrapInfo(User user, String sortBy){
-        return jpaQueryFactory
-                .select(internshipAnnouncement, scrap.id, scrap.color) // tuple -> Scrap 정보 한번에 불러오기
+    public Page<Tuple> findFilteredInternshipsWithScrapInfo(User user, String sortBy, Pageable pageable) {
+        List<Tuple> content = jpaQueryFactory
+                .select(internshipAnnouncement, scrap.id, scrap.color)
                 .from(internshipAnnouncement)
                 .leftJoin(internshipAnnouncement.scraps, scrap).on(scrap.user.eq(user))
                 .where(
@@ -125,9 +125,24 @@ public List<Tuple> findFilteredInternshipsWithScrapInfo(User user, String sortBy
                         sortAnnouncementsByDeadline().asc(),
                         getSortOrder(sortBy)
                 )
+                .offset(pageable.getOffset())
+                .limit(pageable.getPageSize())
                 .fetch();
+
+        JPAQuery<Long> countQuery = jpaQueryFactory
+                .select(internshipAnnouncement.count())
+                .from(internshipAnnouncement)
+                .where(
+                        getJobTypeFilter(user),
+                        getGraduatingFilter(user),
+                        getWorkingPeriodFilter(user),
+                        getStartDateFilter(user)
+                );
+
+        return PageableExecutionUtils.getPage(content, pageable, countQuery::fetchOne);
     }
-
+
+
     private BooleanExpression getGraduatingFilter(User user){
         if(user.getFilter().getGrade() != Grade.SENIOR){
             return internshipAnnouncement.isGraduating.isFalse();

src/main/java/org/terning/terningserver/service/HomeService.java

@@ -1,8 +1,9 @@
 package org.terning.terningserver.service;
 
+import org.springframework.data.domain.Pageable;
 import org.terning.terningserver.dto.user.response.HomeAnnouncementsResponseDto;
 
 public interface HomeService {
 
-    HomeAnnouncementsResponseDto getAnnouncements(Long userId, String sortBy);
+    HomeAnnouncementsResponseDto getAnnouncements(Long userId, String sortBy, Pageable pageable);
 }

src/main/java/org/terning/terningserver/service/HomeServiceImpl.java

@@ -2,6 +2,8 @@
 
 import com.querydsl.core.Tuple;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import org.terning.terningserver.domain.InternshipAnnouncement;
@@ -22,47 +24,71 @@
 @Service
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
-public class HomeServiceImpl implements HomeService{
+public class HomeServiceImpl implements HomeService {
 
     private final InternshipRepository internshipRepository;
     private final UserRepository userRepository;
 
     @Override
-    public HomeAnnouncementsResponseDto getAnnouncements(Long userId, String sortBy){
-        User user = userRepository.findById(userId).orElseThrow(
-                () -> new CustomException(ErrorMessage.NOT_FOUND_USER_EXCEPTION)
-        );
+    public HomeAnnouncementsResponseDto getAnnouncements(Long userId, String sortBy, Pageable pageable) {
+        User user = getUserById(userId);
 
-        // 유저의 필터 정보가 없는 경우
-        if(user.getFilter() == null){
-            return HomeAnnouncementsResponseDto.of(0,List.of());
+        if (user.getFilter() == null) {
+            return createEmptyResponse();
         }
 
-        List<Tuple> announcements = internshipRepository.findFilteredInternshipsWithScrapInfo(user, sortBy);
+        Page<Tuple> pagedAnnouncements = internshipRepository.findFilteredInternshipsWithScrapInfo(user, sortBy, pageable);
 
-        // 해당하는 공고가 없는 경우
-        if(announcements.isEmpty()){
-            return HomeAnnouncementsResponseDto.of(0, List.of());
+        if (pagedAnnouncements.isEmpty()) {
+            return createEmptyResponse();
         }
 
-        List<HomeResponseDto> responseDtos = announcements.stream()
+        List<HomeResponseDto> responseDtos = mapToHomeResponseDtos(pagedAnnouncements);
+
+        return createResponse(pagedAnnouncements, responseDtos);
+    }
+
+    private User getUserById(Long userId) {
+        return userRepository.findById(userId)
+                .orElseThrow(() -> new CustomException(ErrorMessage.NOT_FOUND_USER_EXCEPTION));
+    }
+
+    private HomeAnnouncementsResponseDto createEmptyResponse() {
+        return HomeAnnouncementsResponseDto.of(0, 0, false, List.of());
+    }
+
+    private List<HomeResponseDto> mapToHomeResponseDtos(Page<Tuple> pagedAnnouncements) {
+        return pagedAnnouncements.getContent().stream()
                 .map(tuple -> {
                     InternshipAnnouncement announcement = tuple.get(internshipAnnouncement);
                     Long scrapId = tuple.get(scrap.id);
                     Color color = tuple.get(scrap.color);
-                    boolean isScrapped = (scrapId != null); // 스크랩 여부
 
-                    // scrap 하지 않은 경우 color는 지정되지 않아야 한다.
-                    String colorValue = (isScrapped && color != null) ? color.getColorValue() : null;
+                    boolean isScrapped = isScrapped(scrapId);
+                    String colorValue = determineColorValue(isScrapped, color);
 
                     return HomeResponseDto.of(announcement, isScrapped, colorValue);
                 })
                 .toList();
-
-        return HomeAnnouncementsResponseDto.of(responseDtos.size(), responseDtos);
     }
 
     private boolean isScrapped(Long scrapId) {
         return scrapId != null;
     }
-}
+
+    private String determineColorValue(boolean isScrapped, Color color) {
+        if (isScrapped && color != null) {
+            return color.getColorValue();
+        }
+        return null;
+    }
+
+    private HomeAnnouncementsResponseDto createResponse(Page<Tuple> pagedAnnouncements, List<HomeResponseDto> responseDtos) {
+        return HomeAnnouncementsResponseDto.of(
+                pagedAnnouncements.getTotalPages(),
+                pagedAnnouncements.getTotalElements(),
+                pagedAnnouncements.hasNext(),
+                responseDtos
+        );
+    }
+}