Spring-Kafka Consumer KafkaListener无法将GenericMessage转换为Java Object

Question

我通过在Centos7实例上的Confluent-3.3.0平台上运行的kafka-rest服务发布了一些自定义Java类型'InventoryEvent'的事件，使用以下两个步骤：

将JSON事件POST到kafka-rest的命令

curl -X POST -H "Content-Type:application/vnd.kafka.json.v2+json" --data '{"records" : [{"value" : {"id":1231, "eventType": "inventory.transaction", "qtyLevel" : 2223, "qtyReq" : 2345}}]}' "http://localhost:8082/topics/inventory"

将使用者实例订阅到该主题

curl -X POST -H "Content-Type:application/vnd.kafka.v2+json" --data '{"topics" : ["inventory"]}' http://localhost:8082/consumers/inventory_consumers/instances/consumer_1/subscription

接下来我通过Spring-Kafka应用程序消耗发送给Kafka代理的事件，该应用程序应该使用JSON并通过使用@KafkaListener注释的Consumer侦听器方法将其转换回Java Type，如下所示：

public class InventoryEventReceiver {

    private static final Logger log = LoggerFactory.getLogger(InventoryEventReceiver.class);

    private CountDownLatch latch = new CountDownLatch(1);

    public CountDownLatch getLatch() {
        return latch;
    }

    @KafkaListener(topics="inventory", containerFactory="kafkaListenerContainerFactory")
    public void listenWithHeaders(
            @Payload InventoryEvent event,
            @Header(KafkaHeaders.RECEIVED_TOPIC) String topic,
            @Header(KafkaHeaders.RECEIVED_MESSAGE_KEY) Integer key,
            @Header(KafkaHeaders.RECEIVED_PARTITION_ID) int partition,
            @Header(KafkaHeaders.OFFSET) String offset
            ) {

        System.out.println("EVENT HAS BEEN RECEIVED ");
        System.out.println(event.toString());


        ObjectMapper objectMapper = new ObjectMapper();
        String invEventInString = null;
        try {
            invEventInString = objectMapper.writeValueAsString(event);
            System.out.println(invEventInString);

        } catch (IOException e) {
            e.printStackTrace();
        } 

        latch.countDown();
    }
}

但是我在尝试通过上面的接收器代码使用消息时在KafkaListenerContainer中获得以下错误日志

我尝试但收到相同错误的其他侦听器方法定义是：

使用InventoryEvent对象进行侦听

@KafkaListener(topics="inventory", containerFactory="kafkaListenerContainerFactory")
    public void listenWithHeaders(
            InventoryEvent event )

使用ConsumerRecord进行监听（从错误日志中获取提示）

@KafkaListener(topics="inventory", containerFactory="kafkaListenerContainerFactory")
    public void listen(ConsumerRecord<?,?> record)

下面的我的Receiver配置将InventoryEvent作为值占位符。我将其更改为String并添加了StringJsonMessageConverter

containerFactory.setMessageConverter(new StringJsonMessageConverter());

但它给出了同样的错误。

我是否缺少任何基本的Spring-Kafka配置，如MessageConverter或MessageListener，还是我必须实现自定义MessageConverter以将JSON反序列化为Java类型的InventoryEvent？

@EnableKafka
@Configuration
public class InventoryReceiverConfig {

    @Bean
    public static ConsumerFactory<String, InventoryEvent> consumerFactory() { 
        return new DefaultKafkaConsumerFactory<>(consumerConfigs(), new StringDeserializer(), 
                new JsonDeserializer<>(InventoryEvent.class));
    }

    @Bean
    public static ConcurrentKafkaListenerContainerFactory<String, InventoryEvent> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, InventoryEvent> containerFactory = new ConcurrentKafkaListenerContainerFactory<>();
        containerFactory.setConsumerFactory(consumerFactory());
        containerFactory.setConcurrency(3); 
        containerFactory.getContainerProperties().setPollTimeout(3000);
        return containerFactory;
    }

    @Bean
    public static Map<String, Object> consumerConfigs() {
        Map<String, Object> consumerProps = new HashMap<>();
        consumerProps.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        consumerProps.put(ConsumerConfig.GROUP_ID_CONFIG,"inventory_consumers");
        consumerProps.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class);
        consumerProps.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,JsonDeserializer.class);
        return consumerProps;
    }

    @Bean
    public InventoryEventReceiver receiver() {
        return new InventoryEventReceiver();
    }

}

错误日志：

2017-12-19 13:49:08.671 ERROR 16965 --- [fka-listener-23] o.s.kafka.listener.LoggingErrorHandler   : Error while processing: ConsumerRecord(topic = inventory, partition = 0, offset = 48, CreateTime = 1513691348668, checksum = 537414172, serialized key size = -1, serialized value size = 77, key = null, value = {id=1231, eventType='inventory.transaction', qtyReq='2345', qtyLevel='2223'})

org.springframework.kafka.listener.ListenerExecutionFailedException: Listener method could not be invoked with the incoming message
Endpoint handler details:
Method [public void com.psl.kafka.spring.InventoryEventReceiver.listenWithHeaders(java.lang.String,java.lang.String,java.lang.Integer,int,java.lang.String)]
Bean [com.psl.kafka.spring.InventoryEventReceiver@3ecc1b0b]; nested exception is org.springframework.messaging.converter.MessageConversionException: Cannot handle message; nested exception is org.springframework.messaging.converter.MessageConversionException: Cannot convert from [com.psl.kafka.spring.InventoryEvent] to [java.lang.String] for GenericMessage [payload={id=1231, eventType='inventory.transaction', qtyReq='2345', qtyLevel='2223'}, headers={kafka_offset=48, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=inventory}], failedMessage=GenericMessage [payload={id=1231, eventType='inventory.transaction', qtyReq='2345', qtyLevel='2223'}, headers={kafka_offset=48, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=inventory}]
        at org.springframework.kafka.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:156) ~[spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter.onMessage(RecordMessagingMessageListenerAdapter.java:72) ~[spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter.onMessage(RecordMessagingMessageListenerAdapter.java:47) ~[spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeRecordListener(KafkaMessageListenerContainer.java:764) [spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeListener(KafkaMessageListenerContainer.java:708) [spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.access$2500(KafkaMessageListenerContainer.java:230) [spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer$ListenerInvoker.run(KafkaMessageListenerContainer.java:981) [spring-kafka-1.1.1.RELEASE.jar:na]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_151]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_151]
        at java.lang.Thread.run(Thread.java:748) [na:1.8.0_151]
Caused by: org.springframework.messaging.converter.MessageConversionException: Cannot handle message; nested exception is org.springframework.messaging.converter.MessageConversionException: Cannot convert from [com.psl.kafka.spring.InventoryEvent] to [java.lang.String] for GenericMessage [payload={id=1231, eventType='inventory.transaction', qtyReq='2345', qtyLevel='2223'}, headers={kafka_offset=48, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=inventory}], failedMessage=GenericMessage [payload={id=1231, eventType='inventory.transaction', qtyReq='2345', qtyLevel='2223'}, headers={kafka_offset=48, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=inventory}]
        ... 10 common frames omitted
Caused by: org.springframework.messaging.converter.MessageConversionException: Cannot convert from [com.psl.kafka.spring.InventoryEvent] to [java.lang.String] for GenericMessage [payload={id=1231, eventType='inventory.transaction', qtyReq='2345', qtyLevel='2223'}, headers={kafka_offset=48, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=inventory}]
        at org.springframework.messaging.handler.annotation.support.PayloadArgumentResolver.resolveArgument(PayloadArgumentResolver.java:142) ~[spring-messaging-4.3.13.RELEASE.jar:4.3.13.RELEASE]
        at org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:112) ~[spring-messaging-4.3.13.RELEASE.jar:4.3.13.RELEASE]
        at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:135) ~[spring-messaging-4.3.13.RELEASE.jar:4.3.13.RELEASE]
        at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:107) ~[spring-messaging-4.3.13.RELEASE.jar:4.3.13.RELEASE]
        at org.springframework.kafka.listener.adapter.HandlerAdapter.invoke(HandlerAdapter.java:48) ~[spring-kafka-1.1.1.RELEASE.jar:na]
        at org.springframework.kafka.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:152) ~[spring-kafka-1.1.1.RELEASE.jar:na]
        ... 9 common frames omitted

2017-12-19 13:49:28.869  INFO 16965 --- [o-8080-exec-113] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2017-12-19 13:49:28.889  INFO 16965 --- [o-8080-exec-113] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 20 ms

Answer 1

查看堆栈跟踪：

Method [public void com.psl.kafka.spring.InventoryEventReceiver.listenWithHeaders(java.lang.String,java.lang.String,java.lang.Integer,int,java.lang.String)]

方法签名就像listenWithHeaders(String, String, Integer, int, String)

但你告诉我们完全不同的一个。请确保您在运行时使用正确的代码。

如果你有JsonDeserializer，你真的不需要StringJsonMessageConverter，但必须使用正确的方法，的确......