項目應用1: Spring中的ApplicationEvent與ApplicationListener在項目上的應用

Spring中的ApplicationEvent與ApplicationListener在項目上的應用

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描述:

ApplicationContext事件機制是觀察者設計模式來實現的，通過ApplicationEvent類和ApplicationListener接口，可以實現ApplicationContext事件處理。

使用:

功能上的使用類似發佈和訂閱這種模式

使用步驟:

1、建立event 繼承 ApplicationEvent

/**
 * 1、建立event
 *
 * @author liyue
 * @date 2020-03-26 19:01
 */
public class BookingCreatedEvent extends ApplicationEvent {

    private Booking booking;

    private Action action;

    public enum Action {
        /**
         * 增加方法
         */
        ADD,
        /**
         * 修改方法
         */
        MODIFY,
        /**
         * 刪除方法
         */
        DELETE;
    }


    public BookingCreatedEvent(Object source) {
        super(source);
    }

    public BookingCreatedEvent(Object source, Booking booking, Action action) {
        super(source);
        this.source = source;
        this.booking = booking;
        this.action = action;
    }

    public Booking getBooking() {
        return booking;
    }

    public void setBooking(Booking booking) {
        this.booking = booking;
    }

    public Action getAction() {
        return action;
    }

    public void setAction(Action action) {
        this.action = action;
    }
}

2、建立listener 監聽 需要實現 ApplicationListener

/**
 * 2、建立ApplicationEvent
 *
 * @author liyue
 * @date 2020-03-26 19:05
 */
@Component
public class BookingEventsListener implements ApplicationListener<BookingCreatedEvent> {

    @Override
    public void onApplicationEvent(BookingCreatedEvent bookingCreatedEvent) {

        System.out.println(">>>>>>進入BookingEventsListener監聽方法了>>>>>>");

        switch (bookingCreatedEvent.getAction()) {
            case ADD:
                System.out.println(">>>>>>增加成功>>>>>>");
                return;
            case DELETE:
                System.out.println(">>>>>>刪除成功>>>>>>");
                return;
            case MODIFY:
                System.out.println(">>>>>>修改成功>>>>>>");
                return;
            default:
                return;
        }
    }
}

3、觸發邏輯

/**
 * BookingService 服務類 注意這裏要實現 ApplicationContextAware
 *
 * @author liyue
 * @date 2020-03-26 19:12
 */
@Service
public class BookingServiceImpl implements IBookingService {

    @Resource
    private ApplicationContext publisher;

    @Override
    public void saveBooing(Booking booking) {

        System.out.println(">>>>>開始進行保存Booking操作>>>>>>");

        BookingCreatedEvent bookingCreatedEvent = new BookingCreatedEvent(this, booking, BookingCreatedEvent.Action.DELETE);

        //觸發
        this.publisher.publishEvent(bookingCreatedEvent);

        return;
    }
}

注意：BookingEventsListener在使用的時候，如使用ssm這種框架搭建的項目，一定要能被Spring Bean能掃描到。

4、測試結果

    @Test
    public void test() throws InterruptedException {

        Booking booking = new Booking();
        booking.setId("test");
        booking.setName("test");
        booking.setPassword("test");
        booking.setRealName("test");

        bookingService.saveBooing(booking);
    }