How to use the automatic expiration mechanism in Redis

Automatic expiration mechanism in Redis

Implementation requirements: processing automatic cancellation of expired orders, for example, automatically changing the order status if the order is not paid for 30 minutes

1. Use Redis Key to automatically expire the event Notification
2. Check after 30 minutes using a scheduled task
3. Check according to every minute rotation

CREATE TABLE `order_number` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `order_name` varchar(255) DEFAULT NULL,
  `order_status` int(11) DEFAULT NULL,
  `order_token` varchar(255) DEFAULT NULL,
  `order_id` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=20 DEFAULT CHARSET=utf8;

1. Use the Redis Key automatic expiration mechanism

When our key expires , we can execute our client callback listening method.
Requires configuration in Redis:

1. Open the redis.conf configuration file

vi redis.conf

2. Find notify in the configuration file -keyspace-events

/notify-keyspace-events

3. Modify to notify-keyspace-events Ex

4. Restart redis

##2. SpringBoot integrates key failure monitoring

@Configuration
public class RedisListenerConfig {
    @Bean
    RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
        RedisMessageListenerContainer container = new RedisMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);
        return container;
    }
}

@Component
public class RedisKeyExpirationListener extends KeyExpirationEventMessageListener {
    public RedisKeyExpirationListener(RedisMessageListenerContainer listenerContainer) {
        super(listenerContainer);
    }

    @Resource
    private OrderMapper orderMapper;

    /**
     * 待支付
     */
    private static final Integer ORDER_STAYPAY = 0;

    /**
     * 失效
     */
    private static final Integer ORDER_INVALID = 2;

    /**
     * 使用该方法监听 当我们的key失效的时候执行该方法
     *
     * @param message
     * @param pattern
     */
    @Override
    public void onMessage(Message message, byte[] pattern) {
        String expiraKey = message.toString();
        System.out.println("该key：expiraKey：" + expiraKey + "失效啦~");
        // 前缀判断 orderToken
        OrderEntity orderNumber = orderMapper.getOrderNumber(expiraKey);
        if (orderNumber == null) {
            return;
        }
        // 获取订单状态
        Integer orderStatus = orderNumber.getOrderStatus();
        // 如果该订单状态为待支付的情况下，直接将该订单修改为已经超时
        if (orderStatus.equals(ORDER_STAYPAY)) {
            orderMapper.updateOrderStatus(expiraKey, ORDER_INVALID);
            // 库存加上1
        }
    }
}

@RestController
public class MemberController {
    @Autowired
    private UserMapper userMapper;

    /**
     *
     * @return
     */
    @RequestMapping("/getListMember")
    @Cacheable(cacheNames = "member", key = "'getListMember'")
    public List<MemberEntity> getListMember() {
        return userMapper.findMemberAll();
    }
}

@Data
public class OrderEntity {
    private Long id;
    private String orderName;
    /**
     * 0 待支付 1 已经支付
     */
    private Integer orderStatus;

    private String orderToken;
    private String orderId;

    public OrderEntity(Long id, String orderName, String orderId, String orderToken) {
        this.id = id;
        this.orderName = orderName;
        this.orderId = orderId;
        this.orderToken = orderToken;
    }
}

public interface OrderMapper {

    @Insert("insert into order_number values (null,#{orderName},0,#{orderToken},#{orderId})")
    int insertOrder(OrderEntity OrderEntity);


    @Select("SELECT ID AS ID ,order_name AS ORDERNAME ,order_status AS orderstatus,order_token as ordertoken,order_id as  orderid FROM order_number\n" +
            "where order_token=#{orderToken};")
    OrderEntity getOrderNumber(String orderToken);

    @Update("\n" +
            "\n" +
            "update order_number set order_status=#{orderStatus} where order_token=#{orderToken};")
    int updateOrderStatus(String orderToken, Integer orderStatus);
}

1. Access the addOrder interface

2. View database data

##3. Redis expires after 10 seconds and executes the callback mechanism

4. Check the database again, the status has been modified

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