一文掌握Spring事件驱动模型实战

javaCopy code// 自定义事件类
public class OrderSubmittedEvent extends ApplicationEvent {
    private List<OrderItem> orderItems;
    private Member member;
    private Coupon coupon;
    public OrderSubmittedEvent(Object source, List<OrderItem> orderItems, Member member, Coupon coupon) {
        super(source);
        this.orderItems = orderItems;
        this.member = member;
        this.coupon = coupon;
    }
    public List<OrderItem> getOrderItems() {
        return orderItems;
    }
    public Member getMember() {
        return member;
    }
    public Coupon getCoupon() {
        return coupon;
    }
}

// 事件监听器：扣减商品库存
@Component
public class StockEventHandler implements ApplicationListener<OrderSubmittedEvent> {
    @Autowired
    private StockService stockService;
    @Override
    public void onApplicationEvent(OrderSubmittedEvent event) {
        List<OrderItem> orderItems = event.getOrderItems();
        for (OrderItem orderItem : orderItems) {
            stockService.decreaseStock(orderItem.getProductId(), orderItem.getQuantity());
        }
    }
}

// 事件监听器：扣减会员积分抵钱
@Component
public class PointEventHandler implements ApplicationListener<OrderSubmittedEvent> {
    @Autowired
    private PointService pointService;
    @Override
    public void onApplicationEvent(OrderSubmittedEvent event) {
        Member member = event.getMember();
        int totalPoints = 0;
        List<OrderItem> orderItems = event.getOrderItems();
        for (OrderItem orderItem : orderItems) {
            totalPoints += orderItem.getPoints();
        }
        pointService.decreasePoints(member.getId(), totalPoints);
    }
}

// 事件监听器：核销会员优惠券
@Component
public class CouponEventHandler implements ApplicationListener<OrderSubmittedEvent> {
    @Autowired
    private CouponService couponService;
    @Override
    public void onApplicationEvent(OrderSubmittedEvent event) {
        Coupon coupon = event.getCoupon();
        if (coupon != null) {
            couponService.useCoupon(coupon.getId());
        }
    }
}

// 订单服务类
@Service
public class OrderService {
    @Autowired
    private ApplicationContext applicationContext;
    public void submitOrder(List<OrderItem> orderItems, Member member, Coupon coupon) {
        // 创建订单
        Order order = createOrder(orderItems, member, coupon);
        // 发布订单提交事件
        OrderSubmittedEvent orderSubmittedEvent = new OrderSubmittedEvent(this, orderItems, member, coupon);
        applicationContext.publishEvent(orderSubmittedEvent);
    }
    private Order createOrder(List<OrderItem> orderItems, Member member, Coupon coupon) {
        // 创建订单逻辑
    }
}

// 商品库存服务类
@Service
public class StockService {
    public void decreaseStock(Long productId, int quantity) {
        // 扣减商品库存逻辑
    }
}

// 会员积分服务类
@Service
public class PointService {
    public void decreasePoints(Long memberId, int points) {
        // 扣减会员积分逻辑
    }
}

// 会员优惠券服务类
@Service
public class CouponService {
    public void useCoupon(Long couponId) {
        // 核销会员优惠券逻辑
    }
}

javaCopy code// 事件监听器：扣减商品库存
@Component
@Order(1)
public class StockEventHandler implements ApplicationListener<OrderSubmittedEvent> {
    // ...
}

// 事件监听器：扣减会员积分抵钱
@Component
@Order(2)
public class PointEventHandler implements ApplicationListener<OrderSubmittedEvent> {
    // ...
}