redis是怎么監(jiān)控失效的key

K：keyspace事件，事件以__keyspace@<db>__為前綴進行發(fā)布；????????? E：keyevent事件，事件以__keyevent@<db>__為前綴進行發(fā)布；????????? g：一般性的，非特定類型的命令，比如del，expire，rename等；???????? $：字符串特定命令；????????? l：列表特定命令；????????? s：集合特定命令；????????? h：哈希特定命令；????????? z：有序集合特定命令；????????? x：過期事件，當(dāng)某個鍵過期并刪除時會產(chǎn)生該事件；????????? e：驅(qū)逐事件，當(dāng)某個鍵因maxmemore策略而被刪除時，產(chǎn)生該事件；????????? A：g$lshzxe的別名，因此”AKE”意味著所有事件。</db></db>

127.0.0.1:6379>?PSUBSCRIBE?__keyevent@0__:expired Reading?messages...?(press?Ctrl-C?to?quit) 1)?"psubscribe" 2)?"__keyevent@0__:expired" 3)?(integer)?1

127.0.0.1:6379>?setex?test_key?3?test_value

127.0.0.1:6379>?PSUBSCRIBE?__keyevent@0__:expired Reading?messages...?(press?Ctrl-C?to?quit) 1)?"psubscribe" 2)?"__keyevent@0__:expired" 3)?(integer)?1 1)?"pmessage" 2)?"__keyevent@0__:expired" 3)?"__keyevent@0__:expired" 4)?"test_key"

<!-- redis --> ????????<dependency> ????????????<groupid>org.springframework.boot</groupid> ????????????<artifactid>spring-boot-starter-data-redis</artifactid> ????????</dependency>

import?edu.zut.ding.listener.RedisExpiredListener;import?org.springframework.context.annotation.Bean;import?org.springframework.context.annotation.Configuration;import?org.springframework.data.redis.connection.RedisConnectionFactory;import?org.springframework.data.redis.listener.PatternTopic;import?org.springframework.data.redis.listener.RedisMessageListenerContainer;/** ?*?@Author?lsm ?*?@Date?2018/10/27?20:56 ?*/@Configurationpublic?class?RedisListenerConfig?{????@Bean ????RedisMessageListenerContainer?container(RedisConnectionFactory?connectionFactory)?{  ????????RedisMessageListenerContainer?container?=?new?RedisMessageListenerContainer(); ????????container.setConnectionFactory(connectionFactory);//????????container.addMessageListener(new?RedisExpiredListener(),?new?PatternTopic("__keyevent@0__:expired")); ????????return?container; ????} }

import?edu.zut.ding.constants.SystemConstant;import?edu.zut.ding.enums.OrderState;import?edu.zut.ding.service.OrderService;import?org.springframework.beans.factory.annotation.Autowired;import?org.springframework.data.redis.connection.Message;import?org.springframework.data.redis.listener.KeyExpirationEventMessageListener;import?org.springframework.data.redis.listener.RedisMessageListenerContainer;import?org.springframework.stereotype.Component;/** ?*?監(jiān)聽所有db的過期事件__keyevent@*__:expired" ?*?@author?lsm ?*/@Componentpublic?class?RedisKeyExpirationListener?extends?KeyExpirationEventMessageListener?{????public?RedisKeyExpirationListener(RedisMessageListenerContainer?listenerContainer)?{????????super(listenerContainer); ????}????/** ?????*?針對redis數(shù)據(jù)失效事件，進行數(shù)據(jù)處理 ?????*?@param?message ?????*?@param?pattern ?????*/ ????@Override ????public?void?onMessage(Message?message,?byte[]?pattern)?{????????//?用戶做自己的業(yè)務(wù)處理即可,注意message.toString()可以獲取失效的key ????????String?expiredKey?=?message.toString();????????if(expiredKey.startsWith("Order:")){????????????//如果是Order:開頭的key，進行處理 ????????} ????} }

import?org.springframework.data.redis.connection.Message;import?org.springframework.data.redis.connection.MessageListener;/** ?*?@author?lsm ?*/public?class?RedisExpiredListener?implements?MessageListener?{????/** ?????*?客戶端監(jiān)聽訂閱的topic，當(dāng)有消息的時候，會觸發(fā)該方法; ?????*?并不能得到value,?只能得到key。 ?????*?姑且理解為:?redis服務(wù)在key失效時(或失效后)通知到j(luò)ava服務(wù)某個key失效了,?那么在java中不可能得到這個redis-key對應(yīng)的redis-value。 ?????*??????*?解決方案: ?????*??創(chuàng)建copy/shadow?key,?例如?set?vkey?"vergilyn";?對應(yīng)copykey:?set?copykey:vkey?""?ex?10; ?????*??真正的key是"vkey"(業(yè)務(wù)中使用),?失效觸發(fā)key是"copykey:vkey"(其value為空字符為了減少內(nèi)存空間消耗)。 ?????*??當(dāng)"copykey:vkey"觸發(fā)失效時,?從"vkey"得到失效時的值,?并在邏輯處理完后"del?vkey" ?????*? ?????*?缺陷: ?????*??1:?存在多余的key;?(copykey/shadowkey) ?????*??2:?不嚴謹,?假設(shè)copykey在?12:00:00失效,?通知在12:10:00收到,?這間隔的10min內(nèi)程序修改了key,?得到的并不是?失效時的value. ?????*??(第1點影響不大;?第2點貌似redis本身的Pub/Sub就不是嚴謹?shù)??失效后還存在value的修改,?應(yīng)該在設(shè)計/邏輯上杜絕) ?????*??當(dāng)"copykey:vkey"觸發(fā)失效時,?從"vkey"得到失效時的值,?并在邏輯處理完后"del?vkey" ?????*? ?????*/ ????@Override ????public?void?onMessage(Message?message,?byte[]?bytes)?{????????byte[]?body?=?message.getBody();//?建議使用:?valueSerializer ????????byte[]?channel?=?message.getChannel(); ????????System.out.print("onMessage?>>?"?); ????????System.out.println(String.format("channel:?%s,?body:?%s,?bytes:?%s" ????????????????,new?String(channel),?new?String(body),?new?String(bytes))); ????}  }