解决Redis java.lang.IllegalStateException: Cannot connect, Event executor group is terminated
问题产生背景
-
写了个基于
zset的消息队列（因为公司redis还是3.2.9的，没法用stream），然后有个线程一直轮询取数据。
-
然后我关闭应用时可能会报
Cannot connect, Event executor group is terminated，如下所示。
Exception in thread "loop-redis-queue" java.lang.IllegalStateException: Cannot connect, Event executor group is terminated.
at io.lettuce.core.AbstractRedisClient.initializeChannelAsync(AbstractRedisClient.java:283)
at io.lettuce.core.RedisClient.connectStatefulAsync(RedisClient.java:314)
at io.lettuce.core.RedisClient.connectStandaloneAsync(RedisClient.java:271)
at io.lettuce.core.RedisClient.connect(RedisClient.java:204)
at org.springframework.data.redis.connection.lettuce.StandaloneConnectionProvider.lambda$getConnection$1(StandaloneConnectionProvider.java:113)
at java.util.Optional.orElseGet(Optional.java:267)
at org.springframework.data.redis.connection.lettuce.StandaloneConnectionProvider.getConnection(StandaloneConnectionProvider.java:113)
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getNativeConnection(LettuceConnectionFactory.java:1110)
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getConnection(LettuceConnectionFactory.java:1091)
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getSharedConnection(LettuceConnectionFactory.java:872)
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getConnection(LettuceConnectionFactory.java:347)
at org.springframework.data.redis.core.RedisConnectionUtils.doGetConnection(RedisConnectionUtils.java:134)
at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:97)
at org.springframework.data.redis.core.RedisConnectionUtils.getConnection(RedisConnectionUtils.java:84)
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:212)
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:185)
at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:96)
at org.springframework.data.redis.core.DefaultZSetOperations.rangeByScore(DefaultZSetOperations.java:197)
at com.springboot.sample.redis.DelayingQueueService.pop(DelayingQueueService.java:88)
at com.springboot.sample.redis.DelayingQueueService$1.run(DelayingQueueService.java:124)
问题分析
- 我查到GitHub有在说这个问题，https://github.com/lettuce-io/lettuce-core/issues/1399
- 就说程序关闭的使用不要再去连redis了，得自己处理。
解决方案
- Spring有对关闭程序，销毁bean回调的扩展，例如实现
DisposableBean接口或者 使用@PreDestroy注解。@PreDestroy注解被调用早于DisposableBean接口，我用的@PreDestroy。 - 增加销毁标记
/** 是否销毁标记 volatile 保证可见性 **/
private volatile boolean destroyFlag = false;
- 修改标记
@PreDestroy
public void destroy() throws Exception {
System.out.println("应用程序已关闭");
this.destroyFlag = true;
}
- 然后在轮询的地方加入判断
...省略...
while (!Thread.interrupted() && !destroyFlag) {
...省略...
- 我去掉线程睡眠，测试了大约5次，没有再报异常。结果如下gif图。
