ddd 领域事件 springboot 代码案例

以下是一个使用Spring Boot实现DDD领域事件的案例：

1. 首先，创建一个领域事件类`OrderCreatedEvent`：

```java
public class OrderCreatedEvent {
    private Order order;

    public OrderCreatedEvent(Order order) {
        this.order = order;
    }

    public Order getOrder() {
        return order;
    }
}
```

2. 创建一个领域事件监听器接口`OrderCreatedListener`：

```java
public interface OrderCreatedListener {
    void onOrderCreated(OrderCreatedEvent event);
}
```

3. 创建一个领域事件发布者`OrderEventPublisher`：

```java
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.stereotype.Component;

@Component
public class OrderEventPublisher {
    private final ApplicationEventPublisher applicationEventPublisher;

    public OrderEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }

    public void publishOrderCreatedEvent(Order order) {
        OrderCreatedEvent event = new OrderCreatedEvent(order);
        applicationEventPublisher.publishEvent(event);
    }
}
```

4. 创建一个订单服务类`OrderService`，并在其中处理领域事件：

```java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class OrderService {
    private final OrderEventPublisher orderEventPublisher;

    @Autowired
    public OrderService(OrderEventPublisher orderEventPublisher) {
        this.orderEventPublisher = orderEventPublisher;
    }

    public void createOrder(Order order) {
        // 业务逻辑，创建订单等操作...
        // ...
        // 发布领域事件
        orderEventPublisher.publishOrderCreatedEvent(order);
    }
}
```

5. 创建一个订单控制器类`OrderController`，并接收领域事件：

```java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Mono;

@RestController
public class OrderController {
    private final OrderService orderService;
    private final OrderCreatedListener listener; // 注入领域事件监听器实例

    @Autowired
    public OrderController(OrderService orderService, OrderCreatedListener listener) {
        this.orderService = orderService;
        this.listener = listener; // 将监听器实例注入到控制器中，以便在领域事件发生时通知监听器进行处理。可以在这里使用依赖注入框架如CDI或Spring完成注入，这里省略具体实现。