我正试图使用Spring Cloud Stream 3.0.3.RELEASE处理一些Kafka记录，但Serdes配置遇到了问题，一旦记录进入流管道，就会出现错误。
这是堆栈跟踪：
30-03-2020 19:28:33 ERROR org.apache.kafka.streams.KafkaStreams [application-local,,,]: stream-client [joinPriorityData-applicationId-1302980a-a016-4167-9c0b-750ffb5d107a] All stream threads have died. The instance will be in error state and should be closed.
Exception in thread "joinPriorityData-applicationId-1302980a-a016-4167-9c0b-750ffb5d107a-StreamThread-1" org.apache.kafka.streams.errors.StreamsException: Exception caught in process. taskId=0_0, processor=KSTREAM-SOURCE-0000000001, topic=moaii.security.pe.incidence.queue, partition=0, offset=18108, stacktrace=org.apache.kafka.streams.errors.StreamsException: A serializer (key: org.apache.kafka.common.serialization.StringSerializer / value: org.apache.kafka.common.serialization.ByteArraySerializer) is not compatible to the actual key or value type (key type: java.lang.String / value type: com.vcp.moaii.cep.dto.IncidenceState). Change the default Serdes in StreamConfig or provide correct Serdes via method parameters.
at org.apache.kafka.streams.processor.internals.SinkNode.process(SinkNode.java:94)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamMapValues$KStreamMapProcessor.process(KStreamMapValues.java:41)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamMap$KStreamMapProcessor.process(KStreamMap.java:42)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamFilter$KStreamFilterProcessor.process(KStreamFilter.java:43)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamMapValues$KStreamMapProcessor.process(KStreamMapValues.java:41)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KTableSource$KTableSourceProcessor.process(KTableSource.java:116)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:87)
at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:363)
at org.apache.kafka.streams.processor.internals.AssignedStreamsTasks.process(AssignedStreamsTasks.java:199)
at org.apache.kafka.streams.processor.internals.TaskManager.process(TaskManager.java:425)
at org.apache.kafka.streams.processor.internals.StreamThread.runOnce(StreamThread.java:912)
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:819)
at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:788)
Caused by: java.lang.ClassCastException: class com.vcp.moaii.cep.dto.IncidenceState cannot be cast to class [B (com.vcp.moaii.cep.dto.IncidenceState is in unnamed module of loader 'app'; [B is in module java.base of loader 'bootstrap')
at org.apache.kafka.common.serialization.ByteArraySerializer.serialize(ByteArraySerializer.java:19)
at org.apache.kafka.common.serialization.Serializer.serialize(Serializer.java:62)
at org.apache.kafka.streams.processor.internals.RecordCollectorImpl.send(RecordCollectorImpl.java:163)
at org.apache.kafka.streams.processor.internals.RecordCollectorImpl.send(RecordCollectorImpl.java:103)
at org.apache.kafka.streams.processor.internals.SinkNode.process(SinkNode.java:89)
... 35 more
at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:380)
at org.apache.kafka.streams.processor.internals.AssignedStreamsTasks.process(AssignedStreamsTasks.java:199)
at org.apache.kafka.streams.processor.internals.TaskManager.process(TaskManager.java:425)
at org.apache.kafka.streams.processor.internals.StreamThread.runOnce(StreamThread.java:912)
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:819)
at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:788)
Caused by: org.apache.kafka.streams.errors.StreamsException: A serializer (key: org.apache.kafka.common.serialization.StringSerializer / value: org.apache.kafka.common.serialization.ByteArraySerializer) is not compatible to the actual key or value type (key type: java.lang.String / value type: com.vcp.moaii.cep.dto.IncidenceState). Change the default Serdes in StreamConfig or provide correct Serdes via method parameters.
at org.apache.kafka.streams.processor.internals.SinkNode.process(SinkNode.java:94)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamMapValues$KStreamMapProcessor.process(KStreamMapValues.java:41)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamMap$KStreamMapProcessor.process(KStreamMap.java:42)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamFilter$KStreamFilterProcessor.process(KStreamFilter.java:43)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KStreamMapValues$KStreamMapProcessor.process(KStreamMapValues.java:41)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.kstream.internals.KTableSource$KTableSourceProcessor.process(KTableSource.java:116)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:201)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:180)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:133)
at org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:87)
at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:363)
... 5 more
Caused by: java.lang.ClassCastException: class com.vcp.moaii.cep.dto.IncidenceState cannot be cast to class [B (com.vcp.moaii.cep.dto.IncidenceState is in unnamed module of loader 'app'; [B is in module java.base of loader 'bootstrap')
at org.apache.kafka.common.serialization.ByteArraySerializer.serialize(ByteArraySerializer.java:19)
at org.apache.kafka.common.serialization.Serializer.serialize(Serializer.java:62)
at org.apache.kafka.streams.processor.internals.RecordCollectorImpl.send(RecordCollectorImpl.java:163)
at org.apache.kafka.streams.processor.internals.RecordCollectorImpl.send(RecordCollectorImpl.java:103)
at org.apache.kafka.streams.processor.internals.SinkNode.process(SinkNode.java:89)
... 35 more
这是我的功能：
@Bean
public Function<KTable<String, IncidenceItem>, KStream<String, ?>> joinPriorityData() {
return incidenceStream -> incidenceStream
.toStream()
.filter((key, value) -> filterZoneTypeAndPriority(value))
.selectKey((key, value) -> value.getsInc())
.mapValues((readOnlyKey, value) -> stateMapper.toIncidendeState(value, null));
}
这是我的申请。yml:
spring.json.value.default.type: RawAccounting
spring.cloud.stream:
function.definition: joinPriorityData
bindings:
joinPriorityData-in-0:
destination: moaii.security.pe.incidence.queue
consumer.valueSerde: IncidenceItemSerde
joinPriorityData-out-0:
destination: moaii.security.pe.incidence.state
producer.valueSerde: IncidenceItemSerde
kafka:
binder:
configuration:
auto.commit.interval.ms: 100
auto.offset.reset: latest
streams:
binder:
applicationId: moaii-cep
content-type: application/json
configuration:
default:
key.serde: org.apache.kafka.common.serialization.Serdes$StringSerde
value.serde: org.springframework.kafka.support.serializer.JsonSerde
useNativeDecoding: true
我在很多地方尝试了很多不同的配置，但任何配置似乎都有效。正如您在stacktrace中看到的，默认值Serdes被忽略，而是使用ByteArray。
我也创建了一些自定义serde，将它们声明为bean，并在配置文件中使用，如图所示，但结果相同。
无论如何，我觉得其他配置也被忽略了，例如，我可以看到Ktable如何跳过一些具有null Key的旧记录，然后在读取第一个非null记录时失败，即使我有auto.offset.reset: latest
不能说这是Kafka还是Spring的问题，但不能设法解决
编辑：在此日志中，您可以看到绑定器如何为入站而不是出站获得正确的序列号：
31-03-2020 11:54:24 INFO o.s.c.s.b.k.streams.KafkaStreamsFunctionProcessor [application-local,,,]: Key Serde used for joinPriorityData-in-0: org.apache.kafka.common.serialization.Serdes$StringSerde
31-03-2020 11:54:24 INFO o.s.c.s.b.k.streams.KafkaStreamsFunctionProcessor [application-local,,,]: Value Serde used for joinPriorityData-in-0: com.vcp.moaii.cep.broker.serde.MoaiiSerdes$IncidenceItemSerde
31-03-2020 11:54:27 INFO o.s.c.stream.binder.kafka.streams.KStreamBinder [application-local,,,]: Key Serde used for (outbound) moaii.security.pe.incidence.state: org.apache.kafka.common.serialization.Serdes$StringSerde
31-03-2020 11:54:27 INFO o.s.c.stream.binder.kafka.streams.KStreamBinder [application-local,,,]: Value Serde used for (outbound) moaii.security.pe.incidence.state: org.apache.kafka.common.serialization.Serdes$ByteArraySerde
在出站中，绑定"joinPriorityData-out-0"甚至没有被提及，因为你可以看到
我想知道这个问题是否与您的配置和函数方法有关。试试下面的功能和配置，看看是否有什么不同。
@Bean
public Function<KTable<String, IncidenceItem>, KStream<String, IncidenceState>>
//same as your original code
}
请注意，我为出站KStream添加了参数化类型。这对于活页夹正确推断要使用的Serde类型是必要的。假设IncidenceItem和IncidenceState都是JSON友好对象，则可以忽略提供任何默认的serde。然而，如果您的内部逻辑需要依赖于这些Serdes，那么您仍然需要提供它们。以下是修改后的配置。我删除了不必要的属性或重新排列了它们。
spring.json.value.default.type: RawAccounting
spring.cloud.stream:
function.definition: joinPriorityData
bindings:
joinPriorityData-in-0:
destination: moaii.security.pe.incidence.queue
joinPriorityData-out-0:
destination: moaii.security.pe.incidence.state
kafka:
streams:
binder:
applicationId: moaii-cep
configuration:
auto.commit.interval.ms: 100
auto.offset.reset: latest
default:
key.serde: org.apache.kafka.common.serialization.Serdes$StringSerde
value.serde: org.springframework.kafka.support.serializer.JsonSerde
我不确定您是否同时需要Kafka和Kafka Streams活页夹。从您共享的设置来看，情况并非如此。因此，将所有配置移到Kafka Streams绑定器配置下。
看看这些变化是否有什么不同。
IncidenceState使用两个不同的类加载器加载两次。它用应用程序(系统类加载器(加载一次，用引导类加载器加载一次。
这是卡夫卡的问题。检查这个https://discuss.kotlinlang.org/t/classloading-error-with-kafka-streams/4547这个https://youtrack.jetbrains.com/issue/KT-24966
有一个关于如何修复它的工作。