BridgeLi's Blog

前一段时间有一个需求，需要计数，理所当地的使用了 redis 的 incr 方法。代码大概如下：

    @Scheduled(cron = "0 0/10 * * * ?")
    public void test() {

    long yellowInterval = 5L;
    boolean isReachable = false;
    // TODO
    long delta = isReachable ? -1L : 1L;
    ValueOperations<String, Long> valueOperations = redisTemplate.opsForValue();
    String key = RFID_NETWORK_STATUS_PREFIX + rfDevice.getId();
    Long increment = valueOperations.increment(key, delta);
    if (increment == null || increment <= 0L) {

        }
    } else if (increment >= yellowInterval) {
        if (Constants.RFID_NETWORK_STATUS_GREEN.equals(rfDevice.getNetworkStatus())) {

        }
        if (increment >= yellowInterval * 3) {
            valueOperations.set(key, yellowInterval * 3);
        }
    }

大概就是某个操作之后记一下数，加一或者减一，如果加到了某个值，就把它设置为某个值。我们这里先不考虑并发问题。结果在运行的时候遇到了一个问题，报错信息如下：

2025-07-22 14:51:13,069 [threadPoolTaskScheduler-12] ERROR o.s.s.s.TaskUtils$LoggingErrorHandler 95 - Unexpected error occurred in scheduled task
org.springframework.data.redis.RedisSystemException: Error in execution
	at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:52)
	at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:50)
	at org.springframework.data.redis.connection.lettuce.LettuceExceptionConverter.convert(LettuceExceptionConverter.java:41)
	at org.springframework.data.redis.PassThroughExceptionTranslationStrategy.translate(PassThroughExceptionTranslationStrategy.java:40)
	at org.springframework.data.redis.FallbackExceptionTranslationStrategy.translate(FallbackExceptionTranslationStrategy.java:38)
	at org.springframework.data.redis.connection.lettuce.LettuceConnection.convertLettuceAccessException(LettuceConnection.java:256)
	at org.springframework.data.redis.connection.lettuce.LettuceConnection.await(LettuceConnection.java:969)
	at org.springframework.data.redis.connection.lettuce.LettuceConnection.lambda$doInvoke$4(LettuceConnection.java:826)
	at org.springframework.data.redis.connection.lettuce.LettuceInvoker$Synchronizer.invoke(LettuceInvoker.java:665)
	at org.springframework.data.redis.connection.lettuce.LettuceInvoker.just(LettuceInvoker.java:109)
	at org.springframework.data.redis.connection.lettuce.LettuceStringCommands.incrBy(LettuceStringCommands.java:176)
	at org.springframework.data.redis.connection.DefaultedRedisConnection.incrBy(DefaultedRedisConnection.java:382)
	at org.springframework.data.redis.core.DefaultValueOperations.lambda$increment$1(DefaultValueOperations.java:135)
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:406)
	at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:373)
	at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:97)
	at org.springframework.data.redis.core.DefaultValueOperations.increment(DefaultValueOperations.java:135)
	at cn.bridgeli.schedule.AmsScheduledTask.lambda$ping$1(AmsScheduledTask.java:154)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at cn.bridgeli.schedule.AmsScheduledTask.ping(AmsScheduledTask.java:135)
	at jdk.internal.reflect.GeneratedMethodAccessor249.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84)
	at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
	at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:96)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: io.lettuce.core.RedisCommandExecutionException: ERR value is not an integer or out of range
	at io.lettuce.core.internal.ExceptionFactory.createExecutionException(ExceptionFactory.java:147)
	at io.lettuce.core.internal.ExceptionFactory.createExecutionException(ExceptionFactory.java:116)
	at io.lettuce.core.protocol.AsyncCommand.completeResult(AsyncCommand.java:120)
	at io.lettuce.core.protocol.AsyncCommand.complete(AsyncCommand.java:111)
	at io.lettuce.core.protocol.CommandHandler.complete(CommandHandler.java:746)
	at io.lettuce.core.protocol.CommandHandler.decode(CommandHandler.java:681)
	at io.lettuce.core.protocol.CommandHandler.channelRead(CommandHandler.java:598)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440)
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420)
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:788)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	... 1 common frames omitted

然后用工具查看了一下 Redis 中存储的数据是 15L，那似乎就很明显了，当 incr 返回的数据大于 15 是，往 Redis 中存储了一个 Long 类型的 15，也就是 15L，当下一轮循环的时候对 15L 进行加一或者减一，就报了上面的错，我们都知道 incr 的 value 必须是数字类型，15L 被当成了字符串，所以会报错。
当我们知道是这个原因后其实就很简单了，最简单的一个方案就是：

int yellowInterval = 5L;
ValueOperations<String, Integer> valueOperations = redisTemplate.opsForValue();

也就是将 yellowInterval 定义为 int 类型，而不是 Long 类型，这样在 incr 操作的时候就不会报错了。另外还有一个方案就是修改 Redis 的序列号方式，存储 Long 类型的数字时，不能把它序列化成字符串，而是要处理成数字类型也可以。