kotlin - Spring Cloud Stream Reactive - 处理消息异常

Question

我目前正在 Kotlin 开发一个项目，该项目使用带有反应器的 rabbit 来接收某种 DTO 类型的消息，并在它们达到特定标准时发送它们。在测试我的代码的过程中，我尝试模拟错误的消息输入(因为消息来自外部服务)并查看订阅者的行为。一旦我收到错误的输入消息，订阅者就会停止收听任何新输入并抛出以下异常:

 org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'application.calculateAverage-in-0'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage

然后我尝试运行 official example从 Spring 开始并更改供应商以在第一次调度时发送错误数据，然后发送有效数据并查看行为。
在供应商方面，我添加了一个索引器，仅在第一次运行时发送错误消息。

//Following source and sinks are used for testing only.
//Test source will send data to the same destination where the processor receives data
//Test sink will consume data from the same destination where the processor produces data
// ------ New Code -------
static int x = 0;
// ------ END New Code -------

static class TestSource {

    private AtomicBoolean semaphore = new AtomicBoolean(true);
    private Random random = new Random();
    private int[] ids = new int[]{100100, 100200, 100300};

    @Bean
    public Supplier<?> sendTestData() {

        return () -> {
            // ------ New Code -------
            if(x==0) {
                return "hey";
            }
            x++;
            // ------ END New Code -------
            int id = ids[random.nextInt(3)];
            int temperature = random.nextInt((102 - 65) + 1) + 65;
            Sensor sensor = new Sensor();
            sensor.setId(id);
            sensor.setTemperature(temperature);
            return sensor;
        };
    }
}

订阅方:

@Bean
public Function<Flux<Sensor>, Flux<Average>> calculateAverage() {
    return data -> data.window(Duration.ofSeconds(3)).flatMap(
            window -> window.groupBy(Sensor::getId).flatMap(this::calculateAverage));
}

private Mono<Average> calculateAverage(GroupedFlux<Integer, Sensor> group) {
    return group
            .reduce(new Accumulator(0, 0),
                    (a, d) -> new Accumulator(a.getCount() + 1, a.getTotalValue() + d.getTemperature()))
            .map(accumulator -> new Average(group.key(), (accumulator.getTotalValue()) / accumulator.getCount()));
}

正如我所怀疑的那样，结果表明订户在输入错误后无法继续处理下一条有效消息:

2021-02-21 17:46:57.905  INFO 30702 --- [lOCpiq_lPYTgA-1] o.s.c.s.m.DirectWithAttributesChannel    : Channel 'application.calculateAverage-in-0' has 0 subscriber(s).
2021-02-21 17:46:57.907 ERROR 30702 --- [lOCpiq_lPYTgA-1] onfiguration$FunctionToDestinationBinder : Failure was detected during execution of the reactive function 'calculateAverage'
2021-02-21 17:46:57.910 ERROR 30702 --- [lOCpiq_lPYTgA-1] reactor.core.publisher.Operators         : Operator called default onErrorDropped

org.springframework.messaging.converter.MessageConversionException: Could not read JSON: Unrecognized token 'hey': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
 at [Source: (byte[])"hey"; line: 1, column: 4]; nested exception is com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'hey': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
 at [Source: (byte[])"hey"; line: 1, column: 4]
    at org.springframework.messaging.converter.MappingJackson2MessageConverter.convertFromInternal(MappingJackson2MessageConverter.java:235) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.cloud.stream.converter.ApplicationJsonMessageMarshallingConverter.convertFromInternal(ApplicationJsonMessageMarshallingConverter.java:110) ~[spring-cloud-stream-3.0.11.RELEASE.jar:3.0.11.RELEASE]
    at org.springframework.messaging.converter.AbstractMessageConverter.fromMessage(AbstractMessageConverter.java:197) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.messaging.converter.CompositeMessageConverter.fromMessage(CompositeMessageConverter.java:70) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.fromMessage(SimpleFunctionRegistry.java:932) ~[spring-cloud-function-context-3.0.13.RELEASE.jar:3.0.13.RELEASE]
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.convertInputValueIfNecessary(SimpleFunctionRegistry.java:833) ~[spring-cloud-function-context-3.0.13.RELEASE.jar:3.0.13.RELEASE]
    at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.lambda$convertInputPublisherIfNecessary$9(SimpleFunctionRegistry.java:772) ~[spring-cloud-function-context-3.0.13.RELEASE.jar:3.0.13.RELEASE]
    at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:100) ~[reactor-core-3.3.10.RELEASE.jar:3.3.10.RELEASE]
    at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:192) ~[reactor-core-3.3.10.RELEASE.jar:3.3.10.RELEASE]
    at reactor.core.publisher.EmitterProcessor.drain(EmitterProcessor.java:432) ~[reactor-core-3.3.10.RELEASE.jar:3.3.10.RELEASE]
    at reactor.core.publisher.EmitterProcessor.onNext(EmitterProcessor.java:274) ~[reactor-core-3.3.10.RELEASE.jar:3.3.10.RELEASE]
    at org.springframework.integration.util.IntegrationReactiveUtils.lambda$null$8(IntegrationReactiveUtils.java:133) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:72) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:570) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:520) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109) ~[spring-messaging-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.integration.endpoint.MessageProducerSupport.sendMessage(MessageProducerSupport.java:208) ~[spring-integration-core-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter.access$1300(AmqpInboundChannelAdapter.java:65) ~[spring-integration-amqp-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.lambda$onMessage$0(AmqpInboundChannelAdapter.java:294) ~[spring-integration-amqp-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287) ~[spring-retry-1.2.5.RELEASE.jar:na]
    at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:180) ~[spring-retry-1.2.5.RELEASE.jar:na]
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.onMessage(AmqpInboundChannelAdapter.java:290) ~[spring-integration-amqp-5.3.2.RELEASE.jar:5.3.2.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:1591) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.actualInvokeListener(AbstractMessageListenerContainer.java:1510) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:1498) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:1489) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:1433) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:975) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:921) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$1600(SimpleMessageListenerContainer.java:83) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.mainLoop(SimpleMessageListenerContainer.java:1296) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1202) ~[spring-rabbit-2.2.11.RELEASE.jar:2.2.11.RELEASE]
    at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
2021-02-21 17:47:00.917 ERROR 30702 --- [lOCpiq_lPYTgA-1] o.s.integration.handler.LoggingHandler   : org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'application.calculateAverage-in-0'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=byte[3], headers={amqp_receivedDeliveryMode=PERSISTENT, amqp_receivedExchange=sensor, amqp_deliveryTag=4, deliveryAttempt=3, amqp_consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA, amqp_redelivered=false, amqp_receivedRoutingKey=sensor, amqp_timestamp=Sun Feb 21 17:46:57 IST 2021, amqp_messageId=c6430a53-a916-524f-f436-9fa34f1ba4f9, id=6493e09a-4b4d-37f9-615d-24faa3f3b2f2, amqp_consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, sourceData=(Body:'hey' MessageProperties [headers={}, timestamp=Sun Feb 21 17:46:57 IST 2021, messageId=c6430a53-a916-524f-f436-9fa34f1ba4f9, contentType=application/json, contentLength=0, receivedDeliveryMode=PERSISTENT, priority=0, redelivered=false, receivedExchange=sensor, receivedRoutingKey=sensor, deliveryTag=4, consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA]), contentType=application/json, timestamp=1613922417903}], failedMessage=GenericMessage [payload=byte[3], headers={amqp_receivedDeliveryMode=PERSISTENT, amqp_receivedExchange=sensor, amqp_deliveryTag=4, deliveryAttempt=3, amqp_consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA, amqp_redelivered=false, amqp_receivedRoutingKey=sensor, amqp_timestamp=Sun Feb 21 17:46:57 IST 2021, amqp_messageId=c6430a53-a916-524f-f436-9fa34f1ba4f9, id=6493e09a-4b4d-37f9-615d-24faa3f3b2f2, amqp_consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, sourceData=(Body:'hey' MessageProperties [headers={}, timestamp=Sun Feb 21 17:46:57 IST 2021, messageId=c6430a53-a916-524f-f436-9fa34f1ba4f9, contentType=application/json, contentLength=0, receivedDeliveryMode=PERSISTENT, priority=0, redelivered=false, receivedExchange=sensor, receivedRoutingKey=sensor, deliveryTag=4, consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA]), contentType=application/json, timestamp=1613922417903}]
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:76)
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:570)
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:520)
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
    at org.springframework.integration.endpoint.MessageProducerSupport.sendMessage(MessageProducerSupport.java:208)
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter.access$1300(AmqpInboundChannelAdapter.java:65)
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.lambda$onMessage$0(AmqpInboundChannelAdapter.java:294)
    at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287)
    at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:180)
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.onMessage(AmqpInboundChannelAdapter.java:290)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:1591)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.actualInvokeListener(AbstractMessageListenerContainer.java:1510)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:1498)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:1489)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:1433)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:975)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:921)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$1600(SimpleMessageListenerContainer.java:83)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.mainLoop(SimpleMessageListenerContainer.java:1296)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1202)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=byte[3], headers={amqp_receivedDeliveryMode=PERSISTENT, amqp_receivedExchange=sensor, amqp_deliveryTag=4, deliveryAttempt=3, amqp_consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA, amqp_redelivered=false, amqp_receivedRoutingKey=sensor, amqp_timestamp=Sun Feb 21 17:46:57 IST 2021, amqp_messageId=c6430a53-a916-524f-f436-9fa34f1ba4f9, id=6493e09a-4b4d-37f9-615d-24faa3f3b2f2, amqp_consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, sourceData=(Body:'hey' MessageProperties [headers={}, timestamp=Sun Feb 21 17:46:57 IST 2021, messageId=c6430a53-a916-524f-f436-9fa34f1ba4f9, contentType=application/json, contentLength=0, receivedDeliveryMode=PERSISTENT, priority=0, redelivered=false, receivedExchange=sensor, receivedRoutingKey=sensor, deliveryTag=4, consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA]), contentType=application/json, timestamp=1613922417903}]
    at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:139)
    at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:72)
    ... 23 more

2021-02-21 17:47:03.507  INFO 30702 --- [extShutdownHook] o.s.a.r.l.SimpleMessageListenerContainer : Waiting for workers to finish.
2021-02-21 17:47:03.936 ERROR 30702 --- [lOCpiq_lPYTgA-1] o.s.integration.handler.LoggingHandler   : org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'application.calculateAverage-in-0'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=byte[3], headers={amqp_receivedDeliveryMode=PERSISTENT, amqp_receivedExchange=sensor, amqp_deliveryTag=5, deliveryAttempt=3, amqp_consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA, amqp_redelivered=false, amqp_receivedRoutingKey=sensor, amqp_timestamp=Sun Feb 21 17:46:58 IST 2021, amqp_messageId=b67652f5-1842-4c13-596d-295b36002217, id=4f2a90f9-5aae-0fae-507d-787694f605dc, amqp_consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, sourceData=(Body:'hey' MessageProperties [headers={}, timestamp=Sun Feb 21 17:46:58 IST 2021, messageId=b67652f5-1842-4c13-596d-295b36002217, contentType=application/json, contentLength=0, receivedDeliveryMode=PERSISTENT, priority=0, redelivered=false, receivedExchange=sensor, receivedRoutingKey=sensor, deliveryTag=5, consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA]), contentType=application/json, timestamp=1613922420930}], failedMessage=GenericMessage [payload=byte[3], headers={amqp_receivedDeliveryMode=PERSISTENT, amqp_receivedExchange=sensor, amqp_deliveryTag=5, deliveryAttempt=3, amqp_consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA, amqp_redelivered=false, amqp_receivedRoutingKey=sensor, amqp_timestamp=Sun Feb 21 17:46:58 IST 2021, amqp_messageId=b67652f5-1842-4c13-596d-295b36002217, id=4f2a90f9-5aae-0fae-507d-787694f605dc, amqp_consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, sourceData=(Body:'hey' MessageProperties [headers={}, timestamp=Sun Feb 21 17:46:58 IST 2021, messageId=b67652f5-1842-4c13-596d-295b36002217, contentType=application/json, contentLength=0, receivedDeliveryMode=PERSISTENT, priority=0, redelivered=false, receivedExchange=sensor, receivedRoutingKey=sensor, deliveryTag=5, consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA]), contentType=application/json, timestamp=1613922420930}]
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:76)
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:570)
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:520)
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
    at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
    at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
    at org.springframework.integration.endpoint.MessageProducerSupport.sendMessage(MessageProducerSupport.java:208)
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter.access$1300(AmqpInboundChannelAdapter.java:65)
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.lambda$onMessage$0(AmqpInboundChannelAdapter.java:294)
    at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287)
    at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:180)
    at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.onMessage(AmqpInboundChannelAdapter.java:290)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:1591)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.actualInvokeListener(AbstractMessageListenerContainer.java:1510)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:1498)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:1489)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:1433)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:975)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:921)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$1600(SimpleMessageListenerContainer.java:83)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.mainLoop(SimpleMessageListenerContainer.java:1296)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1202)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=byte[3], headers={amqp_receivedDeliveryMode=PERSISTENT, amqp_receivedExchange=sensor, amqp_deliveryTag=5, deliveryAttempt=3, amqp_consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA, amqp_redelivered=false, amqp_receivedRoutingKey=sensor, amqp_timestamp=Sun Feb 21 17:46:58 IST 2021, amqp_messageId=b67652f5-1842-4c13-596d-295b36002217, id=4f2a90f9-5aae-0fae-507d-787694f605dc, amqp_consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, sourceData=(Body:'hey' MessageProperties [headers={}, timestamp=Sun Feb 21 17:46:58 IST 2021, messageId=b67652f5-1842-4c13-596d-295b36002217, contentType=application/json, contentLength=0, receivedDeliveryMode=PERSISTENT, priority=0, redelivered=false, receivedExchange=sensor, receivedRoutingKey=sensor, deliveryTag=5, consumerTag=amq.ctag-LqdVMYDHHTDatSifcDm9bg, consumerQueue=sensor.anonymous.Q3w6aZhbSlOCpiq_lPYTgA]), contentType=application/json, timestamp=1613922420930}]
    at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:139)
    at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:72)
    ... 23 more

我的问题是如何处理“幕后”发生的异常，例如输入解析？

Answer 1

鉴于响应式(Reactive)编程的性质，这是一个棘手的问题，所以我们可能需要将此讨论变成一个问题，所以请随意 to raise one ，但这是我的看法。
响应式函数和命令式函数之间的根本区别在于工作单元的概念。对于命令式函数，工作单元是单个消息，因此框架保持对流的持续控制，仅通过消息将其传递给函数。因此，您会期望并且理所当然地，无论错误发生在哪里，我们都会有一些用于错误处理的东西——我们确实做到了。
使用响应式函数，世界完全改变了，因为工作单元是整个流，而函数仅充当框架提供的流和用户定义的流操作之间的连接器。在这一点上，s-c-stream 无法控制用户的操作，所以我们的一般建议，特别是考虑到响应式(Reactive) API 在错误处理方面的丰富性，是让用户自己处理。但要理解这不是因为我们不想，而是我们不能，因为那时我们对流没有任何看法。
您的问题确实很独特，因为在执行您定义的步骤之前发生异常，特别是我们提供的类型转换。事实上，我们可以做一些事情来帮助解决这个问题，但我们仍在就这些事情应该是什么寻求共识，直到我们做到快速失败才是解决方案。您可以通过修复输入来克服它，因为它显然不是 JSON 和/或放宽您的函数签名 Function<Flux<byte[]>, Flux<Average>>并自己处理类型转换。
无论如何，正如您所看到的，我愿意接受建议，因此请随时提出和发布并提供您的意见。