Hibernate-在一个事务中保存多个对象

Question

@Service
@Transactional
public class OrderServiceImpl implements OrderService {
    @Autowired
    private ProductRepository productRepository;
    @Autowired 
    private OrderRepository orderRepository;
    @Autowired
    private CartService cartService;
    @Autowired
    private OrderDetailsRepository orderDetailsRepository;


...

public void saveOrder(Order order) {
        Cart cart=order.getCart();
        order.setTotalPrice(cart.getGrandTotal());
        OrderDetails od = new OrderDetails();
        od.setOrder(order);

        for (Map.Entry<Integer, CartItem> entry : cart.getCartItems().entrySet())
        {
            Product product = entry.getValue().getProduct();
            od.setProduct(product);
                od.setQuantity(entry.getValue().getQuantity());
            od.setUnitPrice(product.getUnitPrice());
            orderDetailsRepository.save(od);
        }

        cartService.delete(order.getCart().getCartId());
    }
...

}

Hibernate: 
    insert 
    into
        Orders
        (CustomerID, OrderDate, ShippingDate, TotalPrice) 
    values
        (?, ?, ?, ?)
Hibernate: 
    insert 
    into
        OrderDetails
        (OrderID, ProductID, Quantity, UnitPrice) 
    values
        (?, ?, ?, ?)
Hibernate: 
    update
        OrderDetails 
    set
        OrderID=?,
        ProductID=?,
        Quantity=?,
        UnitPrice=? 
    where
        OrderDetailsID=?

Answer 1

尝试将OrderDetails声明移动到carItems循环：

 public void saveOrder(Order order) {
        Cart cart=order.getCart();
        order.setTotalPrice(cart.getGrandTotal());

        for (Map.Entry<Integer, CartItem> entry : cart.getCartItems().entrySet())
        {
            OrderDetails od = new OrderDetails();
            od.setOrder(order);

            Product product = entry.getValue().getProduct();
            od.setProduct(product);
            od.setQuantity(entry.getValue().getQuantity());
            od.setUnitPrice(product.getUnitPrice());
            orderDetailsRepository.save(od);
        }

        cartService.delete(order.getCart().getCartId());
    }
...

}

在您的原始代码中，Hibernate所做的是：

• 在第一次迭代中，它保存在循环之前声明的OrderDetails实体（并为其生成id)
• 在每隔一次迭代中更新相同的现有实体（在第一次迭代中插入）