feat : service layer를 추가하라.

- ItemService를 추가하라.

- ImageService를 추가하라.

- BestCategoryService를 추가하라.

backend/sidedish/src/main/java/codsquad/team17/sidedish/controller/BestCategoryController.java

@@ -1,68 +1,29 @@
 package codsquad.team17.sidedish.controller;
 
-import codsquad.team17.sidedish.domain.BestCategory;
-import codsquad.team17.sidedish.domain.Item;
-import codsquad.team17.sidedish.dto.BestCategoryDto;
-import codsquad.team17.sidedish.dto.ItemDto;
-import codsquad.team17.sidedish.repository.BestCategoryRepository;
-import codsquad.team17.sidedish.repository.ImageRepository;
-import codsquad.team17.sidedish.repository.ItemRepository;
+import codsquad.team17.sidedish.service.BestCategoryService;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import java.util.List;
-import java.util.stream.Collectors;
-import java.util.stream.LongStream;
-
 @RestController
 @RequestMapping("/best")
 public class BestCategoryController {
-//    private static final int BEST_CATEGORY_ID_RANGE = 5;
-
-    private final ItemRepository itemRepository;
-    private final ImageRepository imageRepository;
-    private final BestCategoryRepository bestCategoryRepository;
+    private final BestCategoryService bestCategoryService;
 
-    public BestCategoryController(ItemRepository itemRepository, ImageRepository imageRepository,
-                                  BestCategoryRepository bestCategoryRepository) {
-        this.itemRepository = itemRepository;
-        this.imageRepository = imageRepository;
-        this.bestCategoryRepository = bestCategoryRepository;
+    public BestCategoryController(BestCategoryService bestCategoryService) {
+        this.bestCategoryService = bestCategoryService;
     }
 
     @GetMapping
     public ResponseEntity getBestCategoryList() {
-        List<Item> distinctBestCategoryList = itemRepository.findDistinctByBestCategoryId();
-
-//        List<BestCategoryDto> result = LongStream.rangeClosed(1, BEST_CATEGORY_ID_RANGE).
-//                mapToObj(bestCategoryId -> getBestCategoryDto(bestCategoryId))
-//                .collect(Collectors.toList());
-
-        List<BestCategoryDto> result = distinctBestCategoryList.stream()
-                .map(item -> getBestCategoryDto(item.getBestCategoryId()))
-                .collect(Collectors.toList());
-
-        return new ResponseEntity(result, HttpStatus.OK);
+        return new ResponseEntity(bestCategoryService.getBestCategoryList(), HttpStatus.OK);
     }
 
     @GetMapping("/{bestCategoryId}")
     public ResponseEntity getBestCategory(@PathVariable Long bestCategoryId) {
-        return new ResponseEntity(getBestCategoryDto(bestCategoryId), HttpStatus.OK);
-    }
-
-    private BestCategoryDto getBestCategoryDto(Long bestCategoryId) {
-        List<Item> items = itemRepository.findAllByBestCategoryId(bestCategoryId);
-        List<ItemDto> itemDtos = items.stream()
-                .map(item -> new ItemDto(item, imageRepository.findByItemIdLimit(item.getItemId())))
-                .collect(Collectors.toList());
-
-        BestCategory bestCategory = bestCategoryRepository.findById(bestCategoryId)
-                .orElseThrow(RuntimeException::new); //TODO exception handling 하기
-
-        return new BestCategoryDto(bestCategory, itemDtos);
+        return new ResponseEntity(bestCategoryService.getBestCategoryDto(bestCategoryId), HttpStatus.OK);
     }
 }

backend/sidedish/src/main/java/codsquad/team17/sidedish/repository/ImageRepository.java

@@ -10,5 +10,5 @@
 public interface ImageRepository extends CrudRepository<Image, Long> {
 
     @Query("SELECT image_id, url, item_id FROM image WHERE item_id=:itemId LIMIT 1;")
-    Image findByItemIdLimit(@Param("itemId") Long itemId);
+    Optional<Image> findTopImageByItemId(@Param("itemId") Long itemId);
 }

backend/sidedish/src/main/java/codsquad/team17/sidedish/service/BestCategoryService.java

@@ -1,4 +1,51 @@
 package codsquad.team17.sidedish.service;
 
+import codsquad.team17.sidedish.domain.BestCategory;
+import codsquad.team17.sidedish.domain.Item;
+import codsquad.team17.sidedish.dto.BestCategoryDto;
+import codsquad.team17.sidedish.dto.ItemDto;
+import codsquad.team17.sidedish.repository.BestCategoryRepository;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Service
 public class BestCategoryService {
+    private final BestCategoryRepository bestCategoryRepository;
+
+    private final ItemService itemService;
+    private final ImageService imageService;
+
+    public BestCategoryService(BestCategoryRepository bestCategoryRepository,
+                               ItemService itemService, ImageService imageService) {
+        this.bestCategoryRepository = bestCategoryRepository;
+        this.itemService = itemService;
+        this.imageService = imageService;
+    }
+
+    public List<BestCategoryDto> getBestCategoryList() {
+        List<Item> distinctBestCategoryList = itemService.findDistinctByBestCategoryId();
+
+        return distinctBestCategoryList.stream()
+                .map(item -> getBestCategoryDto(item.getBestCategoryId()))
+                .collect(Collectors.toList());
+    }
+
+    public BestCategoryDto getBestCategoryDto(Long bestCategoryId) {
+        List<Item> items = itemService.findAllByBestCategoryId(bestCategoryId);
+
+        List<ItemDto> itemDtos = items.stream()
+                .map(item -> new ItemDto(item, imageService.findTopImageByItemId(item.getItemId())))
+                .collect(Collectors.toList());
+
+        BestCategory bestCategory = findBestCategoryId(bestCategoryId);
+
+        return new BestCategoryDto(bestCategory, itemDtos);
+    }
+
+    public BestCategory findBestCategoryId(Long bestCategoryId) {
+        return bestCategoryRepository.findById(bestCategoryId)
+                .orElseThrow(RuntimeException::new); //TODO exception handling 하기
+    }
 }

backend/sidedish/src/main/java/codsquad/team17/sidedish/service/ImageService.java

@@ -0,0 +1,19 @@
+package codsquad.team17.sidedish.service;
+
+import codsquad.team17.sidedish.domain.Image;
+import codsquad.team17.sidedish.repository.ImageRepository;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ImageService {
+    private final ImageRepository imageRepository;
+
+    public ImageService(ImageRepository imageRepository) {
+        this.imageRepository = imageRepository;
+    }
+
+    public Image findTopImageByItemId(Long itemId) {
+        return imageRepository.findTopImageByItemId(itemId)
+                .orElseThrow(RuntimeException::new);
+    }
+}

backend/sidedish/src/main/java/codsquad/team17/sidedish/service/ItemService.java

@@ -0,0 +1,24 @@
+package codsquad.team17.sidedish.service;
+
+import codsquad.team17.sidedish.domain.Item;
+import codsquad.team17.sidedish.repository.ItemRepository;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+public class ItemService {
+    private final ItemRepository itemRepository;
+
+    public ItemService(ItemRepository itemRepository) {
+        this.itemRepository = itemRepository;
+    }
+
+    public List<Item> findAllByBestCategoryId(Long bestCategoryId) {
+        return itemRepository.findAllByBestCategoryId(bestCategoryId);
+    }
+
+    public List<Item> findDistinctByBestCategoryId() {
+        return itemRepository.findDistinctByBestCategoryId();
+    }
+}