Spring boot Spring Kafka使用者KafkaListener无法将GenericMessage转换为Java对象

我通过在Centos7实例上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：

命令将JSON事件发布到kafka rest中

订阅主题的使用者实例

接下来，我将使用通过Spring Kafka应用程序发送给Kafka代理的事件，该应用程序应使用JSON，并通过@KafkaListener注释的消费者侦听器方法将其转换回Java类型，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KafkaListenerContainer中获取下面的错误日志，同时尝试通过上面的接收器代码使用消息

我尝试过但收到相同错误的其他侦听器方法定义如下：

使用InventoryEvent对象侦听

使用ConsumerRecord收听（从错误日志中获取提示）

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，或者我必须实现一个自定义MessageConverter来将JSON反序列化为Java类型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();
    }

}

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)]

方法签名类似于

listenWithHeaders（String，String，Integer，int，String）

但你给我们看的是完全不同的。请务必确保在运行时使用正确的代码

---

如果您有

JsonDeserializer

，您确实不需要

StringJsonMessageConverter

，但必须使用正确的方法，事实上…

我已经显示了侦听器方法签名，如堆栈跟踪中所示。在InventoryEventReceiver类中，我用KafkaListener注释了listenWithHeaders，它的参数（String、String、Integer、int、String）为-InventoryEvent事件、（KafkaHeaders.RECEIVED_主题）String主题、（KafkaHeaders.RECEIVED_消息_键）Integer键，（KafkaHeaders.RECEIVED_PARTITION_ID）int PARTITION，（KafkaHeaders.OFFSET）字符串偏移量。此外，我给出了两个侦听器方法签名，这两个签名都是我在同一个错误中尝试的。我没有使用StringJsonMessageConverter，因为我正在使用正确的方法为Message中的值部分执行JsonSerialize/JsonDeserialize，你是说JsonDeserializer的自定义MessageConverter吗？如果是，你能给出一个简短的例子吗？我会在链接中查看，但在文章中没有提到任何转换器。它只提到处理自定义消息Github是一个很好的共享公共场所。但请记住：这应该尽可能简单，只关注问题。这将使我们很难理解您的业务逻辑。谢谢

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

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

containerFactory.setMessageConverter(new StringJsonMessageConverter());

@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();
    }

}

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

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