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我正在开发一个通过 tcp 套接字从设备读取数据的微服务。微服务也将服务于不同的服务器。因此，设计了分布式结构。在 redis 上创建了一个 RMapCache，以便设备可以被不同的服务定期查询。此 Map 保留进程中设备的当前 IP 信息。不希望同时向同一个 ip 发送多个请求。为将 ip 添加到此地图而创建的方法代码如下。在该方法中，已实现 redisson FairLock 以使代码块线程安全。

RMapCache<String, Long> ipMap=redissonClient.getMapCache("IPMAP");
RLock lock;

public synchronized boolean isIpToMap(String sIp, long timeout) {
            

    lock=redissonClient.getFairLock("anyLock");
    boolean res=false;

    try {
    
        res = lock.tryLock(6, 5, TimeUnit.SECONDS);
                    
        if(res) {
                    
                        
            try {
                            
                return ipMap.fastPutIfAbsent(sIp, Calendar.getInstance().getTimeInMillis(), timeout, TimeUnit.SECONDS);

            } catch (Exception e) {
                            
                e.printStackTrace();
            }finally {
                if (lock.isHeldByCurrentThread()) {
                    lock.unlock();
                }
                        
            }
                    
        }
                
    } catch (Exception e2) {
        e2.printStackTrace();
    }

    return false;

}

但是，当同时运行多个服务实例时，会抛出如下异常。

2021-09-24 18:19:45.242 ERROR 22080 --- [sson-netty-2-34] o.r.client.handler.CommandPubSubDecoder  : Unable to decode data. channel: [id: 0x4f39d587, L:/10.10.8.3:54576 - R:192.168.100.96/192.168.100.96:6379], reply: ReplayingDecoderByteBuf(ridx=103, widx=103)

java.lang.NullPointerException: null
    at org.redisson.client.handler.CommandPubSubDecoder.messageDecoder(CommandPubSubDecoder.java:212) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decodeList(CommandDecoder.java:416) [redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:377) [redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandPubSubDecoder.decodeCommand(CommandPubSubDecoder.java:71) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:134) [redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:91) [redisson-3.12.4.jar:3.12.4]
    at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489) [netty-codec-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:366) [netty-codec-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265) [netty-codec-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:646) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:581) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:498) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:460) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) [netty-common-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.27.Final.jar:4.1.27.Final]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_211]

2021-09-24 18:19:45.253  WARN 22080 --- [sson-netty-2-34] io.netty.channel.DefaultChannelPipeline  : An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.

io.netty.handler.codec.DecoderException: java.lang.NullPointerException
    at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:421) ~[netty-codec-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265) ~[netty-codec-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:646) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:581) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:498) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:460) [netty-transport-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) [netty-common-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.27.Final.jar:4.1.27.Final]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_211]
Caused by: java.lang.NullPointerException: null
    at org.redisson.client.handler.CommandPubSubDecoder.messageDecoder(CommandPubSubDecoder.java:212) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decodeList(CommandDecoder.java:416) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:377) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandPubSubDecoder.decodeCommand(CommandPubSubDecoder.java:71) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:134) ~[redisson-3.12.4.jar:3.12.4]
    at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:91) ~[redisson-3.12.4.jar:3.12.4]
    at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489) ~[netty-codec-4.1.27.Final.jar:4.1.27.Final]
    at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:366) ~[netty-codec-4.1.27.Final.jar:4.1.27.Final]
    ... 28 common frames omitted
4

1 回答 1

0

此问题已在 3.13.4+ 版本中修复。

于 2021-10-11T13:09:25.433 回答