java|springboot使用redis的keyspace notifications java|技术日子

简单定时任务解决方案：使用redis的keyspace notifications（键失效后通知事件）需要注意此功能是在redis 2.8版本以后推出的，因此你服务器上的reids最少要是2.8版本以上；(A)业务场景： 1、当一个业务触发以后需要启动一个定时任务，在指定时间内再去执行一个任务 2、redis的keyspace notifications 会在key失效后发送一个事件，监听此事件的的客户端就可以收到通知 (B)服务准备： 1、修改reids配置文件（redis.conf） redis默认不会开启keyspace notifications，因为开启后会对cpu有消耗备注： E：keyevent事件，事件以__keyevent@__为前缀进行发布； x：过期事件，当某个键过期并删除时会产生该事件；配置如下： notify-keyspace-events "Ex" 2、重启redis就可以了,我们测试一下我们有没有修改成功。开启一个客户端用来监听： [test@127.0.0.1 ~]$ redis-cli 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 开启一个发送key的客户端： [test@127.0.0.1 ~]$ redis-cli 127.0.0.1:6379> set testKey 123 PX 100 OK 127.0.0.1:6379> 结果： [test@127.0.0.1 ~]$ redis-cli 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) "testKey" 这样代表测试成功！(C)springBoot工程引用 1、配置文件 application.properties加入如下配置

spring.redis.host=127.0.0.1 spring.redis.pool.max-active=8 spring.redis.pool.max-idle=8 spring.redis.pool.max-wait=-1 spring.redis.pool.min-idle=0 spring.redis.timeout=3000 spring.redis.password=123456 spring.redis.port=6379

2、在com.xxx.xxx下添加RedisConfiguration类

package com.xxx.xxx; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Value; import org.springframework.cache.annotation.CachingConfigurerSupport; import org.springframework.context.annotation.Bean; import org.springframework.stereotype.Component; import redis.clients.jedis.JedisPool; import redis.clients.jedis.JedisPoolConfig; /** * Created by test on 2017/2/12. */ @Component public class RedisConfiguration extends CachingConfigurerSupport { Logger logger = LoggerFactory.getLogger(RedisConfiguration.class); @Value("${spring.redis.host}") private String host; @Value("${spring.redis.port}") private int port; @Value("${spring.redis.timeout}") private int timeout; @Value("${spring.redis.pool.max-idle}") private int maxIdle; @Value("${spring.redis.pool.max-wait}") private long maxWaitMillis; @Value("${spring.redis.password}") private String password; @Bean public JedisPool redisPoolFactory() { logger.info("JedisPool注入成功！！"); logger.info("redis地址：" + host + ":" + port); JedisPoolConfig jedisPoolConfig = new JedisPoolConfig(); jedisPoolConfig.setMaxIdle(maxIdle); jedisPoolConfig.setMaxWaitMillis(maxWaitMillis); JedisPool jedisPool = new JedisPool(jedisPoolConfig, host, port, timeout,password); return jedisPool; } }3、在com.xxx.xxx下创建redisKeyspace包并创建一个Subscribe.java类 package com.xxx.xxx.redisKeyspace; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import redis.clients.jedis.JedisPubSub; /** * Created by test on 2017/2/12. */ public class Subscribe extends JedisPubSub { private static final Log log= LogFactory.getLog(Subscribe.class); // 初始化按表达式的方式订阅时候的处理 public void onPSubscribe(String pattern, int subscribedChannels) { log.info("Subscribe-onPSubscribe>>>>>>>>>>>>>>>>>>>>>>>>"+pattern + "=" + subscribedChannels); } // 取得按表达式的方式订阅的消息后的处理 public void onPMessage(String pattern, String channel, String message) { try { log.info(pattern + "=" + channel + "=" + message); //在这里写你相关的逻辑代码 }catch (Exception e){ e.printStackTrace(); } } }

3、创建SubscribeThread.java线程类备注：此线程实现了CommandLineRunner，springBoot的CommandLineRunner 可以达到工程已启动就开启一个线程

package com.xxx.xxx.redisKeyspace; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.CommandLineRunner; import org.springframework.stereotype.Component; import redis.clients.jedis.Jedis; import redis.clients.jedis.JedisPool; /** * Created by test on 2017/2/13. */ @Component public class SubscribeThread implements CommandLineRunner { private Log log= LogFactory.getLog(SubscribeThread.class); @Autowired JedisPool jedisPool; @Override public void run(String... strings) throws Exception { Jedis jedis= jedisPool.getResource(); try { //监听所有reids通道中的过期事件 jedis.psubscribe(new Subscribe(), "*"); } catch (Exception e) { jedis.close(); e.printStackTrace(); }finally { jedis.close(); } } }

4、具体业务中向redis中添加key

/** * 添加redis秒定时任务 * @param seconds 秒 */ private void addRedisTimer(String key,int seconds) { Jedis jedis = jedisPool.getResource(); try { if (!jedis.exists(key)) jedis.setex(key,seconds,""); }catch (Exception e){ logger.error("addRedisTimer error: ", e); }finally { jedis.close(); } }

这样我们就实现了springboot已启动就开启一个线程用来监听reids的keyspace notifications事件，然后接收到事件后处理相应的业务代码