在Java中如何开发电子商务订单管理系统_订单管理系统项目实践解析

@Entity
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private Long userId;
    private BigDecimal totalAmount;
    private String status; // 如 "PENDING", "PAID", "SHIPPED"
    private LocalDateTime createTime;

    // getter 和 setter 省略
}

@Service
public class OrderService {

    @Autowired
    private OrderRepository orderRepository;

    @Autowired
    private CartService cartService;

    @Transactional
    public Order createOrder(Long userId) {
        List<CartItem> items = cartService.getCartItems(userId);
        if (items.isEmpty()) {
            throw new RuntimeException("购物车为空");
        }

        BigDecimal total = items.stream()
            .map(item -> item.getPrice().multiply(BigDecimal.valueOf(item.getQuantity())))
            .reduce(BigDecimal.ZERO, BigDecimal::add);

        Order order = new Order();
        order.setUserId(userId);
        order.setTotalAmount(total);
        order.setStatus("PENDING");
        order.setCreateTime(LocalDateTime.now());

        orderRepository.save(order);

        cartService.clearCart(userId); // 清空购物车
        return order;
    }
}

@RestController
@RequestMapping("/api/orders")
public class OrderController {

    @Autowired
    private OrderService orderService;

    @PostMapping("/create")
    public ResponseEntity<Order> createOrder(@RequestParam Long userId) {
        Order order = orderService.createOrder(userId);
        return ResponseEntity.ok(order);
    }

    @GetMapping("/{id}")
    public ResponseEntity<Order> getOrder(@PathVariable Long id) {
        Order order = orderService.findById(id);
        return order != null ? ResponseEntity.ok(order) : ResponseEntity.notFound().build();
    }
}

public enum OrderStatus {
    PENDING, PAID, SHIPPED, DELIVERED, CANCELLED
}