观察者模式-Spring事件机制

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Spring事件机制实现观察者模式
场景:

//订单创建发送短信,邮件
public void save(OrderInfo info) {
     saveOrder(info);
     sendMessage(info);
     sendEmail(info);
     ....
}

缺点:
违背了单一职责原则和开闭原则

优化方案:
1.创建Order事件

@Data
public class OrderCreateEvent extends ApplicationEvent {
    private OrderInfo orderInfo;

    public OrderCreateEvent(OrderInfo orderInfo) {
        super(orderInfo);
        this.orderInfo = orderInfo;
    }
}

2.创建监听类,监听事件

@Slf4j
@Component
@Order(1)
public class OrderMessageListener implements ApplicationListener<OrderCreateEvent> {
    @Override
    public void onApplicationEvent(OrderCreateEvent event) {
        OrderInfo orderInfo = event.getOrderInfo();
        sendMessage(orderInfo);
    }
}

@Slf4j
@Component
@Order(2)
public class OrderEmailListener implements ApplicationListener<OrderCreateEvent> {
    @Override
    public void onApplicationEvent(OrderCreateEvent event) {
        OrderInfo orderInfo = event.getOrderInfo();
        sendEmail(orderInfo);
    }
}

3.推送事件

//订单创建发送短信,邮件
@Autowired
private ApplicationContext applicationContext;

public void save(OrderInfo info) {
     saveOrder(info);
     applicationContext.publishEvent(new OrderCreateEvent(info));
     ....
}