feat: Search API 리팩터링 및 중복 요청 500 에러 해결

booklog/src/main/java/com/example/booklog/domain/library/books/entity/Books.java

@@ -139,8 +139,13 @@ public void addBookAuthor(BookAuthors bookAuthor) {
     }
 
     public void replaceBookAuthors(List<BookAuthors> newMappings) {
+        // ✅ orphan removal을 위해 기존 매핑 clear
         this.bookAuthors.clear();
-        for (BookAuthors m : newMappings) addBookAuthor(m);
+
+        // ✅ 새로운 매핑 추가
+        for (BookAuthors m : newMappings) {
+            addBookAuthor(m);
+        }
     }
 
     public void addBookGenre(BookGenres bookGenre) {

booklog/src/main/java/com/example/booklog/domain/library/books/service/BookImportService.java

@@ -14,11 +14,11 @@
 import com.example.booklog.domain.library.books.service.client.KakaoBookClient;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import jakarta.persistence.EntityManager;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
-import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.List;
@@ -32,6 +32,7 @@ public class BookImportService {
     private final AuthorsRepository authorsRepository;
     private final BookSearchConverter bookSearchConverter;
     private final ObjectMapper objectMapper; // ✅ Spring Bean 주입
+    private final EntityManager entityManager; // ✅ orphan removal 즉시 처리용
 
     /**
      * 카카오 도서 검색 -> books/authors/book_authors 업서트 -> 검색 응답 반환
@@ -112,9 +113,18 @@ public BookSearchResponse searchAndUpsert(String query, int page, int size) {
                         .build());
             }
 
+            // ✅ 기존 매핑 삭제를 먼저 DB에 반영
+            if (book.getId() != null) {
+                book.getBookAuthors().clear();
+                booksRepository.save(book);
+                entityManager.flush();
+            }
+
+            // ✅ 새로운 매핑 추가
             book.replaceBookAuthors(mappings);
 
             Books saved = booksRepository.save(book);
+
             items.add(bookSearchConverter.toResponse(saved, doc));
         }
 

booklog/src/main/java/com/example/booklog/domain/search/controller/SearchController.java

@@ -0,0 +1,66 @@
+package com.example.booklog.domain.search.controller;
+
+import com.example.booklog.domain.search.dto.BookSearchResponse;
+import com.example.booklog.domain.search.service.BookSearchService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.*;
+
+/**
+ * 통합 검색 API 컨트롤러
+ * - 도서 검색: /api/v1/search/books
+ * - 작가 검색: /api/v1/search/authors (추후 구현)
+ * - 통합 검색: /api/v1/search (추후 구현)
+ */
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/api/v1/search")
+public class SearchController {
+
+    private final BookSearchService bookSearchService;
+
+    /**
+     * 도서 검색
+     * GET /api/v1/search/books?query={검색어}&page={페이지}&size={크기}
+     */
+    @GetMapping("/books")
+    public BookSearchResponse searchBooks(
+            @RequestParam String query,
+            @RequestParam(defaultValue = "1") int page,
+            @RequestParam(defaultValue = "10") int size
+    ) {
+        return bookSearchService.searchBooks(query, page, size);
+    }
+
+    /**
+     * 작가 검색 (추후 구현)
+     * GET /api/v1/search/authors?query={검색어}&page={페이지}&size={크기}
+     */
+    // TODO: 작가 검색 구현
+    // @GetMapping("/authors")
+    // public AuthorSearchResponse searchAuthors(...)
+
+    /**
+     * 통합 검색 (추후 구현)
+     * GET /api/v1/search?query={검색어}&page={페이지}&size={크기}
+     */
+    // TODO: 통합 검색 구현
+    // @GetMapping
+    // public IntegratedSearchResponse search(...)
+
+    /**
+     * 최근 검색어 조회 (추후 구현)
+     * GET /api/v1/search/recent
+     */
+    // TODO: 최근 검색어 구현
+    // @GetMapping("/recent")
+    // public RecentSearchResponse getRecentSearches()
+
+    /**
+     * 추천 검색어 조회 (추후 구현)
+     * GET /api/v1/search/recommendations
+     */
+    // TODO: 추천 검색어 구현
+    // @GetMapping("/recommendations")
+    // public RecommendationSearchResponse getRecommendations()
+}
+

booklog/src/main/java/com/example/booklog/domain/search/dto/BookSearchItemResponse.java

@@ -0,0 +1,19 @@
+package com.example.booklog.domain.search.dto;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+/**
+ * 도서 검색 결과 항목 DTO
+ */
+public record BookSearchItemResponse(
+        Long bookId,
+        String title,
+        String thumbnailUrl,
+        String publisherName,
+        String isbn13,
+        List<String> authors,
+        List<String> translators,
+        LocalDateTime publishedAt
+) {}
+

booklog/src/main/java/com/example/booklog/domain/search/dto/BookSearchResponse.java

@@ -0,0 +1,15 @@
+package com.example.booklog.domain.search.dto;
+
+import java.util.List;
+
+/**
+ * 도서 검색 응답 DTO
+ */
+public record BookSearchResponse(
+        int page,
+        int size,
+        boolean isEnd,
+        int totalCount,
+        List<BookSearchItemResponse> items
+) {}
+

booklog/src/main/java/com/example/booklog/domain/search/service/BookSearchService.java

@@ -0,0 +1,69 @@
+package com.example.booklog.domain.search.service;
+
+import com.example.booklog.domain.library.books.service.BookImportService;
+import com.example.booklog.domain.search.dto.BookSearchItemResponse;
+import com.example.booklog.domain.search.dto.BookSearchResponse;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+/**
+ * 도서 검색 서비스
+ * - 카카오 API를 통한 도서 검색 및 DB 업서트
+ */
+@Service
+@RequiredArgsConstructor
+public class BookSearchService {
+
+    private final BookImportService bookImportService;
+
+    /**
+     * 도서 검색 및 업서트
+     * @param query 검색어
+     * @param page 페이지 번호
+     * @param size 페이지 크기
+     * @return 검색 결과
+     */
+    public BookSearchResponse searchBooks(String query, int page, int size) {
+        // 기존 BookImportService의 검색 로직 활용
+        com.example.booklog.domain.library.books.dto.BookSearchResponse legacyResponse =
+                bookImportService.searchAndUpsert(query, page, size);
+
+        // DTO 변환 (legacy -> search domain)
+        return convertToSearchResponse(legacyResponse);
+    }
+
+    /**
+     * legacy DTO를 search domain DTO로 변환
+     */
+    private BookSearchResponse convertToSearchResponse(
+            com.example.booklog.domain.library.books.dto.BookSearchResponse legacyResponse) {
+
+        var items = legacyResponse.items().stream()
+                .map(this::convertToSearchItem)
+                .toList();
+
+        return new BookSearchResponse(
+                legacyResponse.page(),
+                legacyResponse.size(),
+                legacyResponse.isEnd(),
+                legacyResponse.totalCount(),
+                items
+        );
+    }
+
+    private BookSearchItemResponse convertToSearchItem(
+            com.example.booklog.domain.library.books.dto.BookSearchItemResponse legacyItem) {
+
+        return new BookSearchItemResponse(
+                legacyItem.bookId(),
+                legacyItem.title(),
+                legacyItem.thumbnailUrl(),
+                legacyItem.publisherName(),
+                legacyItem.isbn13(),
+                legacyItem.authors(),
+                legacyItem.translators(),
+                legacyItem.publishedAt()
+        );
+    }
+}
+