#13 API 고급 - 실무 필수 최적화

jpashop/src/main/java/jpabook/jpashop/api/MemberApiController.java

@@ -25,7 +25,7 @@ public class MemberApiController {
     public CreateMemberResponse saveMemberV1(@RequestBody @Valid Member member){
         // @RequestBody : JSON으로 온 body를 Member에 그대로 매핑해서 넣어준다.
 
-        Long id = memberService.join(member);
+        Long id = memberService.join(member); // OSIV OFF라면 이렇게 반환된 후엔 영속성 컨텍스트도 끝, 데이터베이스 커넥션도 끝
         return new CreateMemberResponse(id);
     }
 

jpashop/src/main/java/jpabook/jpashop/api/OrderApiController.java

@@ -10,6 +10,7 @@
 import jpabook.jpashop.repository.order.query.OrderQueryDto;
 import jpabook.jpashop.repository.order.query.OrderQueryRepository;
 import jpabook.jpashop.repository.OrderSearch;
+import jpabook.jpashop.service.query.OrderQueryService;
 import lombok.Data;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
@@ -62,21 +63,14 @@ public List<OrderDto> ordersV2() {
         return result;
     }
 
+    private final OrderQueryService orderQueryService;
+
     // 엔티티를 조회해 DTO로 반환
     // 쿼리 수 최적화 + 페이징 X
     // 컬렉션까지 한 번에 fetch join
     @GetMapping("/api/v3/orders")
-    public List<OrderDto> ordersV3() {
-        List<Order> orders = orderRepository.findAllWithItem();
-
-        for (Order order : orders) {
-            System.out.println("order ref="+ order + " id="+ order.getId());
-        }
-        List<OrderDto> result = orders.stream()
-                .map(o -> new OrderDto(o))
-                .collect(toList());
-
-        return result;
+    public List<jpabook.jpashop.service.query.OrderDto> ordersV3() {
+        return orderQueryService.ordersV3();
     }
 
     // 엔티티를 조회해 DTO로 반환

jpashop/src/main/java/jpabook/jpashop/service/MemberService.java

@@ -41,6 +41,8 @@ public class MemberService {
      * 회원 가입
      */
     @Transactional // 읽기 전용인 기능이 많으니까 전체를 readOnly = true로 해두고 이 기능만 false로
+    // 영속성 컨텍스트 만들어지고 데이터베이스 커넥션 가져오고
+    // OSIV OFF라면 로직이 끝난 후 데이터 베이스 커넥션 플러시 커밋하고 영속성 컨텍스트를 없애고 데이터 베이스 커넥션 반환
     public Long join(Member member){
         validateDuplicateMember(member); // 중복 회원 검증
         memberRepository.save(member);

jpashop/src/main/java/jpabook/jpashop/service/query/OrderDto.java

@@ -0,0 +1,42 @@
+package jpabook.jpashop.service.query;
+
+import jpabook.jpashop.api.OrderApiController;
+import jpabook.jpashop.domain.Address;
+import jpabook.jpashop.domain.Order;
+import jpabook.jpashop.domain.OrderItem;
+import jpabook.jpashop.domain.OrderStatus;
+import lombok.Data;
+import lombok.Getter;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+
+@Getter
+public class OrderDto {
+
+        private Long orderId;
+        private String name;
+        private LocalDateTime orderDate;
+        private OrderStatus orderStatus;
+        private Address address;
+        private List<OrderItemDto> orderItems;
+        // List<OrderItem>이면 DTO 안에 엔티티가 있는 상황.
+        // 엔티티에 대한 의존을 완전히 끊어야 한다.
+        // OrderItem도 DTO로 바꿔야 한다.
+
+        public OrderDto(Order order) {
+            orderId = order.getId();
+            name = order.getMember().getName();
+            orderDate = order.getOrderDate();
+            orderStatus = order.getStatus();
+            address = order.getDelivery().getAddress();
+            orderItems = order.getOrderItems().stream()
+                    .map(orderItem -> new OrderItemDto(orderItem))
+                    .collect(toList());
+        }
+    }
+
+
+

jpashop/src/main/java/jpabook/jpashop/service/query/OrderItemDto.java

@@ -0,0 +1,17 @@
+package jpabook.jpashop.service.query;
+
+import jpabook.jpashop.domain.OrderItem;
+import lombok.Getter;
+
+@Getter
+class OrderItemDto {
+
+    private String itemName;
+    private int orderPrice;
+    private int count;
+    public OrderItemDto(OrderItem orderItem) {
+        itemName = orderItem.getItem().getName();
+        orderPrice = orderItem.getOrderPrice();
+        count = orderItem.getCount();
+    }
+}

jpashop/src/main/java/jpabook/jpashop/service/query/OrderQueryService.java

@@ -0,0 +1,31 @@
+package jpabook.jpashop.service.query;
+
+import jpabook.jpashop.api.OrderApiController;
+import jpabook.jpashop.domain.Order;
+import jpabook.jpashop.repository.OrderRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+
+import static java.util.stream.Collectors.toList;
+
+@Service
+@Transactional(readOnly = true)
+@RequiredArgsConstructor
+public class OrderQueryService {
+    private final OrderRepository orderRepository;
+    public List<OrderDto> ordersV3() {
+        List<Order> orders = orderRepository.findAllWithItem();
+
+        for (Order order : orders) {
+            System.out.println("order ref="+ order + " id="+ order.getId());
+        }
+        List<OrderDto> result = orders.stream()
+                .map(o -> new OrderDto(o))
+                .collect(toList());
+
+        return result;
+    }
+}

jpashop/src/main/resources/application.yml

@@ -6,6 +6,7 @@ spring:
     driver-class-name: org.h2.Driver
 
   jpa:
+#    open-in-view: false
     hibernate:
       ddl-auto: create
     # create : 애플리케이션 실행 시점에 테이블 드롭하고 다시 만든다.