【Redis系列】Spring boot实现监听Redis key失效事件

talk is cheap, show me the code.

一、开启Redis key过期提醒

• 方式二：修改配置文件

  redis.conf

  # 默认 notify-keyspace-events ""
  notify-keyspace-events Ex
  

• 方式二：命令行开启

  CONFIG SET notify-keyspace-events Ex
  CONFIG GET notify-keyspace-events
  

二、notify-keyspace-events

notify-keyspace-events 选项的默认值为空

notify-keyspace-events 的参数可以是以下字符的任意组合， 它指定了服务器该发送哪些类型的通知。

字符	发送的通知
K	键空间通知，所有通知以 keyspace@ 为前缀
E	键事件通知，所有通知以 keyevent@ 为前缀
g	DEL 、 EXPIRE 、 RENAME 等类型无关的通用命令的通知
$	字符串命令的通知
l	列表命令的通知
s	集合命令的通知
h	哈希命令的通知
z	有序集合命令的通知
x	过期事件：每当有过期键被删除时发送
e	驱逐(evict)事件：每当有键因为 maxmemory 政策而被删除时发送
A	参数 g$lshzxe 的别名

三、Coding

1. 初始化一个Spring Boot项目

2. pom.xml

   <dependencies>
   		<dependency>
   			<groupId>org.springframework.boot</groupId>
   			<artifactId>spring-boot-starter-data-redis</artifactId>
   		</dependency>
   		<dependency>
   			<groupId>org.projectlombok</groupId>
   			<artifactId>lombok</artifactId>
   		</dependency>
   	</dependencies>
   

3. 定义配置类RedisListenerConfig

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

4. 定义数据生产类ProviderDataToRedis

   @Slf4j
   @Component
   public class ProviderDataToRedis implements CommandLineRunner {
   
   	@Autowired
   	private StringRedisTemplate stringRedisTemplate;
   
   	@Override
   	public void run(String... args) throws Exception {
   		int[] num = new int[]{1};
   		Random random = new Random();
   		while (true) {
   			int max = random.nextInt(5);
   			IntStream.range(0, max).forEach(n -> stringRedisTemplate.opsForValue().set(String.format("mq:s1:%s", ++num[0]), "已预订", 5, TimeUnit.SECONDS));
   			log.info("放了 {} 条数据到redis...", max);
   			TimeUnit.SECONDS.sleep(3);
   		}
   	}
   }
   

5. 定义监听器 实现KeyExpirationEventMessageListener接口

   查看源码发现，该接口监听所有db的过期事件keyevent@*:expired"

   定义Status1ExpirationListener监听状态1到期

   @Slf4j
   @Component
   public class Status1ExpirationListener extends KeyExpirationEventMessageListener {
   
   	public Status1ExpirationListener(RedisMessageListenerContainer listenerContainer) {
   		super(listenerContainer);
   	}
   
   	@Autowired
   	private StringRedisTemplate stringRedisTemplate;
   
   	@Override
   	public void onMessage(Message message, byte[] pattern) {
   		// 用户做自己的业务处理即可,注意message.toString()可以获取失效的key
   		String expiredKey = message.toString();
   		if (expiredKey.startsWith("mq:s1:")) {
   			log.info("-----------------------------------");
   			log.info(String.format("过期key[%s]", expiredKey));
   			String newKey = String.format("mq:s2:%s", expiredKey.substring(6));
   			String newValue = "行程中";
   			stringRedisTemplate.opsForValue().set(newKey, newValue, 3, TimeUnit.SECONDS);
   			log.info(String.format("%s: %s", newKey, newValue));
   			log.info("-----------------------------------");
   		}
   	}
   
   }
   

   定义Status2ExpirationListener监听状态2到期

   @Slf4j
   @Component
   public class Status2ExpirationListener extends KeyExpirationEventMessageListener {
   
   	public Status2ExpirationListener(RedisMessageListenerContainer listenerContainer) {
   		super(listenerContainer);
   	}
   
   	@Override
   	public void onMessage(Message message, byte[] pattern) {
   		// 用户做自己的业务处理即可,注意message.toString()可以获取失效的key
   		String expiredKey = message.toString();
   		if (expiredKey.startsWith("mq:s2:")) {
   			log.info("***********************************");
   			log.info(String.format("过期key[%s]", expiredKey));
   			log.info("[{}]行程已完成，修改数据库状态。", newKey);
   			log.info("***********************************");
   		}
   	}
   
   }
   

四、测试输出

...
2021-01-25 23:16:58.012  INFO 55511 --- [           main] n.y.tools.listener.ProviderDataToRedis      : 放了 4 条数据到redis...
2021-01-25 23:17:00.037  INFO 55511 --- [ container-1070] c.i.r.l.Status1ExpirationListener        : -----------------------------------
2021-01-25 23:17:00.037  INFO 55511 --- [ container-1070] c.i.r.l.Status1ExpirationListener        : 过期key[mq:s1:272]
2021-01-25 23:17:00.037  INFO 55511 --- [ container-1072] c.i.r.l.Status1ExpirationListener        : -----------------------------------
2021-01-25 23:17:00.037  INFO 55511 --- [ container-1072] c.i.r.l.Status1ExpirationListener        : 过期key[mq:s1:271]
2021-01-25 23:17:00.039  INFO 55511 --- [ container-1070] c.i.r.l.Status1ExpirationListener        : mq:s2:272: 行程中
2021-01-25 23:17:00.039  INFO 55511 --- [ container-1072] c.i.r.l.Status1ExpirationListener        : mq:s2:271: 行程中
2021-01-25 23:17:00.039  INFO 55511 --- [ container-1070] c.i.r.l.Status1ExpirationListener        : -----------------------------------
2021-01-25 23:17:00.039  INFO 55511 --- [ container-1072] c.i.r.l.Status1ExpirationListener        : -----------------------------------
2021-01-25 23:17:00.140  INFO 55511 --- [ container-1075] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.140  INFO 55511 --- [ container-1075] c.i.r.l.Status2ExpirationListener        : 过期key[mq:s2:270]
2021-01-25 23:17:00.140  INFO 55511 --- [ container-1075] c.i.r.l.Status2ExpirationListener        : [270]行程已完成，修改数据库状态。
2021-01-25 23:17:00.140  INFO 55511 --- [ container-1075] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1077] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1077] c.i.r.l.Status2ExpirationListener        : 过期key[mq:s2:269]
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1079] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1079] c.i.r.l.Status2ExpirationListener        : 过期key[mq:s2:268]
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1077] c.i.r.l.Status2ExpirationListener        : [269]行程已完成，修改数据库状态。
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1077] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1079] c.i.r.l.Status2ExpirationListener        : [268]行程已完成，修改数据库状态。
2021-01-25 23:17:00.242  INFO 55511 --- [ container-1079] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.546  INFO 55511 --- [ container-1081] c.i.r.l.Status2ExpirationListener        : ***********************************
2021-01-25 23:17:00.546  INFO 55511 --- [ container-1081] c.i.r.l.Status2ExpirationListener        : 过期key[mq:s2:267]
2021-01-25 23:17:00.546  INFO 55511 --- [ container-1081] c.i.r.l.Status2ExpirationListener        : [267]行程已完成，修改数据库状态。
2021-01-25 23:17:00.546  INFO 55511 --- [ container-1081] c.i.r.l.Status2ExpirationListener        : ***********************************
...

五、一直增加的线程数

从测试输出的日志中可以看出，线程一直在增加，这个问题还有待解决！

六、参考

http://redisdoc.com/topic/notification.html