feat: 상품 조회 기능 전체 개선 - Redis 캐시, 커서 페이징, 인기 상품 API

상품 목록/상세 조회 성능 향상 및 무한 스크롤, 인기 상품 기능 추가
- ProductDetailCache: 상품 상세 정보 Redis 캐싱
- ProductListCache: 상품 목록 조회 결과 캐싱 (LIKES_DESC 정렬만)
- 커서 기반 페이징 구현으로 무한 스크롤 지원
- CursorPageInfo, ProductCursorSearchCommand 추가
- /products/cursor 엔드포인트 추가
- 인기 상품 조회 API 추가 (좋아요 수 기준 Top 10)
- /products/popular 엔드포인트 추가
- 브랜드 필터링 기능 추가
- ProductRepository에 커서 및 인기 상품 조회 메서드 추가

Author: sylee6529

apps/commerce-api/src/main/java/com/loopers/application/product/CursorPageInfo.java

@@ -0,0 +1,23 @@
+package com.loopers.application.product;
+
+import lombok.Getter;
+
+import java.util.List;
+
+@Getter
+public class CursorPageInfo<T> {
+
+    private final List<T> content;
+    private final String nextCursor;
+    private final boolean hasNext;
+
+    private CursorPageInfo(List<T> content, String nextCursor, boolean hasNext) {
+        this.content = content;
+        this.nextCursor = nextCursor;
+        this.hasNext = hasNext;
+    }
+
+    public static <T> CursorPageInfo<T> of(List<T> content, String nextCursor, boolean hasNext) {
+        return new CursorPageInfo<>(content, nextCursor, hasNext);
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/product/ProductCursorSearchCommand.java

@@ -0,0 +1,28 @@
+package com.loopers.application.product;
+
+import com.loopers.domain.product.enums.ProductSortCondition;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+public class ProductCursorSearchCommand {
+
+    private final Long brandId;
+    private final String keyword;
+    private final ProductSortCondition sort;
+    private final String cursor;
+    private final int size;
+    private final Long memberIdOrNull;
+
+    public static ProductCursorSearchCommand of(Long brandId, String keyword, ProductSortCondition sort, String cursor, int size, Long memberIdOrNull) {
+        return ProductCursorSearchCommand.builder()
+                .brandId(brandId)
+                .keyword(keyword)
+                .sort(sort)
+                .cursor(cursor)
+                .size(size)
+                .memberIdOrNull(memberIdOrNull)
+                .build();
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/product/ProductDetailInfo.java

@@ -1,13 +1,16 @@
 package com.loopers.application.product;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
 import com.loopers.domain.common.vo.Money;
 import com.loopers.domain.product.vo.Stock;
 import lombok.Builder;
 
 @Builder
+@JsonDeserialize(builder = ProductDetailInfo.ProductDetailInfoBuilder.class)
 public class ProductDetailInfo {
-    
+
     private final Long id;
     private final String name;
     private final String description;
@@ -17,7 +20,7 @@ public class ProductDetailInfo {
     private final Stock stock;
     private final int likeCount;
     private final boolean isLikedByMember;
-    
+
     public Long getId() { return id; }
     public String getName() { return name; }
     public String getDescription() { return description; }
@@ -26,7 +29,11 @@ public class ProductDetailInfo {
     public Money getPrice() { return price; }
     public Stock getStock() { return stock; }
     public int getLikeCount() { return likeCount; }
-    
+
     @JsonProperty("likedByMember")
     public boolean isLikedByMember() { return isLikedByMember; }
+
+    @JsonPOJOBuilder(withPrefix = "")
+    public static class ProductDetailInfoBuilder {
+    }
 }

apps/commerce-api/src/main/java/com/loopers/application/product/ProductFacade.java

@@ -1,39 +1,129 @@
 package com.loopers.application.product;
 
+import com.loopers.domain.like.service.LikeReadService;
 import com.loopers.domain.product.service.ProductReadService;
 import com.loopers.domain.product.command.ProductSearchFilter;
+import com.loopers.domain.product.enums.ProductSortCondition;
+import com.loopers.infrastructure.cache.ProductDetailCache;
+import com.loopers.infrastructure.cache.ProductListCache;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Component;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.util.List;
+
 @RequiredArgsConstructor
 @Component
 @Transactional
 public class ProductFacade {
 
     private final ProductReadService productReadService;
+    private final LikeReadService likeReadService;
+    private final ProductDetailCache productDetailCache;
+    private final ProductListCache productListCache;
 
     @Transactional(readOnly = true)
     public Page<ProductSummaryInfo> getProducts(ProductSearchCommand command) {
+        // Cache only for LIKES_DESC sort
+        if (command.getSort() == ProductSortCondition.LIKES_DESC) {
+            return productListCache.get(
+                    command.getBrandId(),
+                    command.getSort(),
+                    command.getPage(),
+                    command.getSize()
+            ).orElseGet(() -> {
+                Page<ProductSummaryInfo> result = fetchProducts(command);
+                productListCache.set(
+                        command.getBrandId(),
+                        command.getSort(),
+                        command.getPage(),
+                        command.getSize(),
+                        result
+                );
+                return result;
+            });
+        }
+
+        return fetchProducts(command);
+    }
+
+    private Page<ProductSummaryInfo> fetchProducts(ProductSearchCommand command) {
         ProductSearchFilter filter = ProductSearchFilter.of(
+                command.getBrandId(),
                 command.getKeyword(),
                 command.getSort()
         );
 
         Pageable pageable = PageRequest.of(command.getPage(), command.getSize());
 
         return productReadService.getProducts(
-                filter, 
-                pageable, 
+                filter,
+                pageable,
                 command.getMemberIdOrNull()
         );
     }
 
     @Transactional(readOnly = true)
-    public ProductDetailInfo getProductDetail(Long productId, String memberIdOrNull) {
-        return productReadService.getProductDetail(productId, memberIdOrNull);
+    public CursorPageInfo<ProductSummaryInfo> getProductsByCursor(ProductCursorSearchCommand command) {
+        ProductSearchFilter filter = ProductSearchFilter.of(
+                command.getBrandId(),
+                command.getKeyword(),
+                command.getSort()
+        );
+
+        return productReadService.getProductsByCursor(
+                filter,
+                command.getCursor(),
+                command.getSize(),
+                command.getMemberIdOrNull()
+        );
+    }
+
+    @Transactional(readOnly = true)
+    public ProductDetailInfo getProductDetail(Long productId, Long memberIdOrNull) {
+        // 1. 캐시에서 상품 정보 조회 (isLikedByMember=false인 상태)
+        ProductDetailInfo cachedInfo = productDetailCache.get(productId)
+                .orElseGet(() -> {
+                    // 캐시 miss: DB 조회 (isLikedByMember는 나중에 계산)
+                    ProductDetailInfo result = productReadService.getProductDetail(productId, null);
+                    productDetailCache.set(productId, result);
+                    return result;
+                });
+
+        // 2. 로그인하지 않은 경우 바로 반환
+        if (memberIdOrNull == null) {
+            return cachedInfo;  // isLikedByMember=false 그대로
+        }
+
+        // 3. isLikedByMember만 동적 계산
+        boolean isLiked = likeReadService.isLikedBy(memberIdOrNull, productId);
+
+        // 4. isLikedByMember 필드만 교체해서 반환
+        return ProductDetailInfo.builder()
+                .id(cachedInfo.getId())
+                .name(cachedInfo.getName())
+                .description(cachedInfo.getDescription())
+                .brandName(cachedInfo.getBrandName())
+                .brandDescription(cachedInfo.getBrandDescription())
+                .price(cachedInfo.getPrice())
+                .stock(cachedInfo.getStock())
+                .likeCount(cachedInfo.getLikeCount())
+                .isLikedByMember(isLiked)  // ⭐ 동적 계산
+                .build();
+    }
+
+    @Transactional(readOnly = true)
+    public List<ProductSummaryInfo> getPopularProducts(Long memberIdOrNull) {
+        // 캐시 제거 - 순수 DB 조회
+        return productReadService.getPopularProducts(memberIdOrNull);
+    }
+
+    @Transactional(readOnly = true)
+    public List<ProductSummaryInfo> getBrandPopularProducts(Long brandId, int limit, Long memberIdOrNull) {
+        // 캐시 제거 - 순수 DB 조회
+        return productReadService.getBrandPopularProducts(brandId, limit, memberIdOrNull);
     }
 }

apps/commerce-api/src/main/java/com/loopers/application/product/ProductSearchCommand.java

@@ -7,15 +7,17 @@
 @Getter
 @Builder
 public class ProductSearchCommand {
-    
+
+    private final Long brandId;
     private final String keyword;
     private final ProductSortCondition sort;
     private final int page;
     private final int size;
-    private final String memberIdOrNull;
-    
-    public static ProductSearchCommand of(String keyword, ProductSortCondition sort, int page, int size, String memberIdOrNull) {
+    private final Long memberIdOrNull;
+
+    public static ProductSearchCommand of(Long brandId, String keyword, ProductSortCondition sort, int page, int size, Long memberIdOrNull) {
         return ProductSearchCommand.builder()
+                .brandId(brandId)
                 .keyword(keyword)
                 .sort(sort)
                 .page(page)

apps/commerce-api/src/main/java/com/loopers/application/product/ProductSummaryInfo.java

@@ -1,25 +1,32 @@
 package com.loopers.application.product;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
 import com.loopers.domain.common.vo.Money;
 import lombok.Builder;
 
 @Builder
+@JsonDeserialize(builder = ProductSummaryInfo.ProductSummaryInfoBuilder.class)
 public class ProductSummaryInfo {
-    
+
     private final Long id;
     private final String name;
     private final String brandName;
     private final Money price;
     private final int likeCount;
     private final boolean isLikedByMember;
-    
+
     public Long getId() { return id; }
     public String getName() { return name; }
     public String getBrandName() { return brandName; }
     public Money getPrice() { return price; }
     public int getLikeCount() { return likeCount; }
-    
+
     @JsonProperty("likedByMember")
     public boolean isLikedByMember() { return isLikedByMember; }
+
+    @JsonPOJOBuilder(withPrefix = "")
+    public static class ProductSummaryInfoBuilder {
+    }
 }

apps/commerce-api/src/main/java/com/loopers/domain/product/Product.java

@@ -67,6 +67,10 @@ public void decreaseLikeCount() {
         }
     }
 
+    public void setLikeCount(int likeCount) {
+        this.likeCount = likeCount;
+    }
+
     public boolean isStockAvailable(int requiredQuantity) {
         return this.stock.isAvailable(requiredQuantity);
     }

apps/commerce-api/src/main/java/com/loopers/domain/product/command/ProductSearchFilter.java

@@ -7,12 +7,14 @@
 @Getter
 @Builder
 public class ProductSearchFilter {
-    
+
+    private final Long brandId;
     private final String keyword;
     private final ProductSortCondition sortCondition;
-    
-    public static ProductSearchFilter of(String keyword, ProductSortCondition sortCondition) {
+
+    public static ProductSearchFilter of(Long brandId, String keyword, ProductSortCondition sortCondition) {
         return ProductSearchFilter.builder()
+                .brandId(brandId)
                 .keyword(keyword)
                 .sortCondition(sortCondition)
                 .build();

apps/commerce-api/src/main/java/com/loopers/domain/product/repository/ProductRepository.java

@@ -16,11 +16,19 @@ public interface ProductRepository {
 
     Page<Product> findAll(ProductSearchFilter filter, Pageable pageable);
 
+    List<Product> findAllByCursor(ProductSearchFilter filter, String cursor, int size);
+
     Product save(Product product);
 
     int decreaseStock(Long productId, int quantity);
 
     int incrementLikeCount(Long productId);
 
     int decrementLikeCount(Long productId);
+
+    int updateLikeCount(Long productId, long count);
+
+    List<Product> findTopByLikeCount(int limit);
+
+    List<Product> findTopByBrandIdAndLikeCount(Long brandId, int limit);
 }