jpashop : 컬렉션 조회 v6 (jpa -dto 직접조회, 플랫 데이터)

jpashop/src/main/java/com/example/jpashop/api/OrderApiController.java

@@ -4,6 +4,8 @@ import com.example.jpashop.domain.Order;
 import com.example.jpashop.domain.OrderItem;
 import com.example.jpashop.repository.OrderRepository;
 import com.example.jpashop.repository.OrderSearch;
+import com.example.jpashop.repository.order.query.OrderFlatDto;
+import com.example.jpashop.repository.order.query.OrderItemQueryDto;
 import com.example.jpashop.repository.order.query.OrderQueryDto;
 import com.example.jpashop.repository.order.query.OrderQueryRepository;
 import lombok.RequiredArgsConstructor;
@@ -14,6 +16,8 @@ import org.springframework.web.bind.annotation.RestController;
 import java.util.List;
 import java.util.stream.Collectors;
 
+import static java.util.stream.Collectors.*;
+
 @RestController
 @RequiredArgsConstructor
 public class OrderApiController {
@@ -68,4 +72,16 @@ public class OrderApiController {
     public List<OrderQueryDto> ordersV5() {
         return orderQueryRepository.findAllByDto_optimization();
     }
+
+    @GetMapping("/api/v6/orders")
+    public List<OrderQueryDto> ordersV6() {
+        List<OrderFlatDto> flats = orderQueryRepository.findAllByDto_flat();
+
+        return flats.stream()
+                .collect(groupingBy(o -> new OrderQueryDto(o.getOrderId(), o.getName(), o.getOrderDate(), o.getOrderStatus(), o.getAddress()),
+                        mapping(o -> new OrderItemQueryDto(o.getOrderId(), o.getItemName(), o.getOrderPrice(), o.getCount()), toList())
+                )).entrySet().stream()
+                .map(e -> new OrderQueryDto(e.getKey().getOrderId(), e.getKey().getName(), e.getKey().getOrderDate(), e.getKey().getOrderStatus(), e.getKey().getAddress(), e.getValue()))
+                .collect(toList());
+    }
 }

jpashop/src/main/java/com/example/jpashop/repository/order/query/OrderFlatDto.java

@@ -0,0 +1,32 @@
+package com.example.jpashop.repository.order.query;
+
+import com.example.jpashop.domain.Address;
+import com.example.jpashop.domain.OrderStatus;
+import lombok.Data;
+
+import java.time.LocalDateTime;
+
+@Data
+public class OrderFlatDto {
+
+    private Long orderId;
+    private String name;
+    private LocalDateTime orderDate;
+    private OrderStatus orderStatus;
+    private Address address;
+
+    private String itemName;
+    private int orderPrice;
+    private int count;
+
+    public OrderFlatDto(Long orderId, String name, LocalDateTime orderDate, OrderStatus orderStatus, Address address, String itemName, int orderPrice, int count) {
+        this.orderId = orderId;
+        this.name = name;
+        this.orderDate = orderDate;
+        this.orderStatus = orderStatus;
+        this.address = address;
+        this.itemName = itemName;
+        this.orderPrice = orderPrice;
+        this.count = count;
+    }
+}

jpashop/src/main/java/com/example/jpashop/repository/order/query/OrderQueryDto.java

@@ -4,11 +4,13 @@ import com.example.jpashop.domain.Address;
 import com.example.jpashop.domain.OrderStatus;
 import lombok.AllArgsConstructor;
 import lombok.Data;
+import lombok.EqualsAndHashCode;
 
 import java.time.LocalDateTime;
 import java.util.List;
 
 @Data
+@EqualsAndHashCode(of = "orderId")
 public class OrderQueryDto {
 
     private Long orderId;
@@ -25,4 +27,13 @@ public class OrderQueryDto {
         this.orderStatus = orderStatus;
         this.address = address;
     }
+
+    public OrderQueryDto(Long orderId, String name, LocalDateTime orderDate, OrderStatus orderStatus, Address address, List<OrderItemQueryDto> orderItems) {
+        this.orderId = orderId;
+        this.name = name;
+        this.orderDate = orderDate;
+        this.orderStatus = orderStatus;
+        this.address = address;
+        this.orderItems = orderItems;
+    }
 }

jpashop/src/main/java/com/example/jpashop/repository/order/query/OrderQueryRepository.java

@@ -34,6 +34,18 @@ public class OrderQueryRepository {
         return result;
     }
 
+    public List<OrderFlatDto> findAllByDto_flat() {
+        return em.createQuery(
+                "select new com.example.jpashop.repository.order.query.OrderFlatDto(o.id, m.name, o.orderDate, o.status, d.address, i.name, oi.orderPrice, oi.count)" +
+                        " from Order o" +
+                        " join o.member m" +
+                        " join o.delivery d" +
+                        " join o.orderItems oi" +
+                        " join oi.item i", OrderFlatDto.class)
+                .getResultList();
+    }
+
+
     private Map<Long, List<OrderItemQueryDto>> findOrderItemMap(List<Long> orderIds) {
         List<OrderItemQueryDto> orderItems = em.createQuery(
                 "select new com.example.jpashop.repository.order.query.OrderItemQueryDto(oi.order.id, i.name, oi.orderPrice, oi.count)" +