springboot整合redis使用Lettuce客户端超时问题

现象：

Springboot 接入redis后发现隔一段时间连接会超时 command timed out。

org.springframework.dao.QueryTimeoutException: Redis command timed out; nested exception is io.lettuce.core.RedisCommandTimeoutException: Command timed
 out after 5 second(s)
    at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.JAVA:70)
    at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:41)
    at org.springframework.data.redis.PassThroughExceptionTranslationStrategy.translate(PassThroughExceptionTranslationStrategy.java:44)
    at org.springframework.data.redis.FallbackExceptionTranslationStrategy.translate(FallbackExceptionTranslationStrategy.java:42)
    at org.springframework.data.redis.connection.lettuce.LettuceConnection.convertLettuceAccessException(LettuceConnection.java:273)
    at org.springframework.data.redis.connection.lettuce.LettuceStringCommands.convertLettuceAccessException(LettuceStringCommands.java:799)
    at org.springframework.data.redis.connection.lettuce.LettuceStringCommands.get(LettuceStringCommands.java:68)
    at org.springframework.data.redis.connection.DefaultedRedisConnection.get(DefaultedRedisConnection.java:266)
    at org.springframework.data.redis.core.DefaultValueOperations$1.inRedis(DefaultValueOperations.java:57)
    at org.springframework.data.redis.core.AbstractOperations$ValueDeserializingRedisCallback.doInRedis(AbstractOperations.java:60)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:228)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:188)
    at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:96)
    at org.springframework.data.redis.core.DefaultValueOperations.get(DefaultValueOperations.java:53)

原因：

spring-data-redis内置了两款驱动，jedis和lettuce。springboot1.X版本默认jedis实现，springboot2.X默认lettuce实现。

lettuce：基�.NETty实现，线程安全，但默认只有一个实例。

jedis：直连redis服务端，一般配合连接池使用，可以增加物理连接。

lettuce只要断掉连接后，自己并没有去重连的机制，最后导致time out。

解决办法：

方法一：

更改连接redis的连接方式，使用jedis连接

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-redis</artifactId>
	<exclusions>
		<!-- 过滤lettuce，使用jedis作为redis客户端 -->
		<exclusion>
			<groupId>io.lettuce</groupId>
			<artifactId>lettuce-core</artifactId>
		</exclusion>
	</exclusions>
</dependency>
<dependency>
	<groupId>redis.clients</groupId>
	<artifactId>jedis</artifactId>
</dependency>
<dependency>
	<groupId>org.Apache.commons</groupId>
	<artifactId>commons-pool2</artifactId>
</dependency>

配置文件

spring:
  redis:
    password: xxx
    host: 172.16.0.x
    port: 6579
    timeout: 5000
    jedis:
      pool:
              #最大连接数据库连接数,设 0 为没有限制
        max-active: 8
              #最大等待连接中的数量,设 0 为没有限制
        max-idle: 8
              #最大建立连接等待时间。如果超过此时间将接到异常。设为-1表示无限制。
        max-wait: -1ms
              #最小等待连接中的数量,设 0 为没有限制
        min-idle: 0
    #lettuce:
      #pool:
        #max-active: ${redis.config.maxTotal:1024}
        #max-idle: ${redis.config.maxIdle:50}
        #min-idle: ${redis.config.minIdle:1}
        #max-wait: ${redis.config.maxWaitMillis:5000}

方法二：

在开发的时候，使用到Lettuce连接redis，一段时间后不操作，再去操作redis，会报连接超时错误，在其重连后又可使用。

原因是：Lettuce 自适应拓扑刷新（Adaptive updates）与定时拓扑刷新（Periodic updates） 是默认关闭的导致问题的出现

1、重写连接工厂实例，更改其
LettuceClientConfiguration 为开启拓扑更新

@Configuration
public class RedisConfig {
 
 
    @Autowired
    private RedisProperties redisProperties;
 
    //这是固定的模板
    //自己定义了一个RedisTemplate
    @Bean
    @SuppressWarnings("all")
    public RedisTemplate<String, Object> redisTemplate(@Qualifier("lettuceConnectionFactoryUvPv") RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
 
        //Json序列化配置
        Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<Object>(Object.class);
        ObjectMApper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.activateDefaultTyping(om.getPolymorphicTypeValidator());
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        //解决序列化问题
        om.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        jackson2JsonRedisSerializer.setObjectMapper(om);
 
        //String的序列化
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
 
        //key采用String的序列化方式
        template.setKeySerializer(stringRedisSerializer);
        //hash的key也采用String的序列化方式
        template.setHashKeySerializer(stringRedisSerializer);
 
        //value序列化方式采用jackson
        template.setValueSerializer(jackson2JsonRedisSerializer);
 
        //hash的value序列化方式采用jackson
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        template.afterPropertiesSet();
 
        return template;
    }
 
    /**
     * 为RedisTemplate配置Redis连接工厂实现
     * LettuceConnectionFactory实现了RedisConnectionFactory接口
     * UVPV用Redis
     *
     * @return 返回LettuceConnectionFactory
     */
    @Bean(destroyMethod = "destroy")
    //这里要注意的是，在构建LettuceConnectionFactory 时，如果不使用内置的destroyMethod，可能会导致Redis连接早于其它Bean被销毁
    public LettuceConnectionFactory lettuceConnectionFactoryUvPv() throws Exception {
 
//        List<String> clusterNodes = redisProperties.getCluster().getNodes();
//        Set<RedisNode> nodes = new HashSet<>();
//        clusterNodes.forEach(address -> nodes.add(new RedisNode(address.split(":")[0].trim(), Integer.parseInt(address.split(":")[1]))));
//        RedisClusterConfiguration clusterConfiguration = new RedisClusterConfiguration();
//        clusterConfiguration.setClusterNodes(nodes);
//        clusterConfiguration.setPassword(RedisPassword.of(redisProperties.getPassword()));
//        clusterConfiguration.setMaxRedirects(redisProperties.getCluster().getMaxRedirects());
 
        //我使用的是单机redis，集群使用上面注释的代码
        Set<RedisNode> nodes = new HashSet<>();
        nodes.add(new RedisNode(redisProperties.getHost(), redisProperties.getPort()));
 
 
        RedisStandaloneConfiguration  redisStandaloneConfiguration=new RedisStandaloneConfiguration();
        redisStandaloneConfiguration.setHostName(redisProperties.getHost());
        redisStandaloneConfiguration.setPassword(redisProperties.getPassword());
        redisStandaloneConfiguration.setDatabase(redisProperties.getDatabase());
        redisStandaloneConfiguration.setPort(redisProperties.getPort());
 
        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
        poolConfig.setMaxIdle(redisProperties.getLettuce().getPool().getMaxIdle());
        poolConfig.setMinIdle(redisProperties.getLettuce().getPool().getMinIdle());
        poolConfig.setMaxTotal(redisProperties.getLettuce().getPool().getMaxActive());
 
        return new LettuceConnectionFactory(redisStandaloneConfiguration, getLettuceClientConfiguration(poolConfig));
    }
 
    /**
     * 配置LettuceClientConfiguration 包括线程池配置和安全项配置
     *
     * @param genericObjectPoolConfig common-pool2线程池
     * @return lettuceClientConfiguration
     */
    private LettuceClientConfiguration getLettuceClientConfiguration(GenericObjectPoolConfig genericObjectPoolConfig) {
        /*
        ClusterTopologyRefreshOptions配置用于开启自适应刷新和定时刷新。如自适应刷新不开启，Redis集群变更时将会导致连接异常！
         */
        ClusterTopologyRefreshOptions topologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
                //开启自适应刷新
                //.enableAdaptiveRefreshTrigger(ClusterTopologyRefreshOptions.RefreshTrigger.MOVED_REDIRECT, ClusterTopologyRefreshOptions.RefreshTrigger.PERSISTENT_RECONNECTS)
                //开启所有自适应刷新，MOVED，ASK，PERSISTENT都会触发
                .enableAllAdaptiveRefreshTriggers()
                // 自适应刷新超时时间(默认30秒)
                .adaptiveRefreshTriggersTimeout(Duration.ofSeconds(25)) //默认关闭开启后时间为30秒
                // 开周期刷新
                .enablePeriodicRefresh(Duration.ofSeconds(20))  // 默认关闭开启后时间为60秒 ClusterTopologyRefreshOptions.DEFAULT_REFRESH_PERIOD 60  .enablePeriodicRefresh(Duration.ofSeconds(2)) = .enablePeriodicRefresh().refreshPeriod(Duration.ofSeconds(2))
                .build();
        return LettucePoolingClientConfiguration.builder()
                .poolConfig(genericObjectPoolConfig)
                .clientOptions(ClusterClientOptions.builder().topologyRefreshOptions(topologyRefreshOptions).build())
                //将appID传入连接，方便Redis监控中查看
                //.clientName(appName + "_lettuce")
                .build();
    }
 
}

2、SpringBoot2.3.x后，可使用配置文件中开启lettuce的拓扑刷新

lettuce:
    pool:
      max-active: 20
      max-wait: -1ms
      max-idle: 10
      min-idle: 2
    cluster:
      refresh:
        adaptive: true
        #20秒自动刷新一次
        period: 20