使用 Spring Kafka 反序列化来自同一 Kafka 主题的不同 JSON 有效负载

Question

我正在尝试反序列化来自同一个 Kafka 主题的不同 JSON 有效负载。此处提出的其他问题引导我进行了第一次尝试，但我无法让它运行。

正如加里提到的（这里）有一些提示（JsonSerializer.ADD_TYPE_INFO_HEADERS），但是当我发送和接收两条消息时，我得到一个异常。

org.springframework.kafka.listener.ListenerExecutionFailedException: Listener method could not be invoked with the incoming message
Endpoint handler details:
Method [public void com.foo.message.ConsumerImpl.consumeSelf(java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.util.Map<java.lang.String, java.lang.Object>,com.foo.message.KafkaMessage,org.apache.kafka.clients.consumer.ConsumerRecord<java.lang.String, java.lang.Object>)]
Bean [com.foo.message.ConsumerImpl@6df2a206]; nested exception is org.springframework.messaging.converter.MessageConversionException: Cannot handle message; nested exception is org.springframework.messaging.converter.MessageConversionException: Cannot convert from [com.foo.message.KafkaMessageWithAdditionalField] to [com.foo.message.KafkaMessage] for GenericMessage [payload=com.foo.message.KafkaMessageWithAdditionalField@4e3168f7, headers={kafka_offset=22, kafka_consumer=org.apache.kafka.clients.consumer.KafkaConsumer@c0e2fcf, kafka_timestampType=CREATE_TIME, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=fromBar, kafka_receivedTimestamp=1548310583481}], failedMessage=GenericMessage [payload=com.foo.message.KafkaMessageWithAdditionalField@4e3168f7, headers={kafka_offset=22, kafka_consumer=org.apache.kafka.clients.consumer.KafkaConsumer@c0e2fcf, kafka_timestampType=CREATE_TIME, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=fromBar, kafka_receivedTimestamp=1548310583481}]
    at org.springframework.kafka.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:292) ~[spring-kafka-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter.onMessage(RecordMessagingMessageListenerAdapter.java:79) ~[spring-kafka-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter.onMessage(RecordMessagingMessageListenerAdapter.java:50) ~[spring-kafka-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeOnMessage(KafkaMessageListenerContainer.java:1207) [spring-kafka-2.2.2.RELEASE.jar:2.2.2.RELEASE]

...

LoggingErrorHandler 在 ConsumerRecord 中已经提到了一个（正确的）值。

2019-01-24 07:16:27.630 ERROR 27204 --- [ntainer#2-0-C-1] o.s.kafka.listener.LoggingErrorHandler   : Error while processing: ConsumerRecord(topic = fromBar, partition = 0, offset = 22, CreateTime = 1548310583481, serialized key size = -1, serialized value size = 196, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = com.foo.bar.message.KafkaMessageWithAdditionalField@4e3168f7)

首先我的配置：

@EnableKafka
@Configuration
public class KafkaConsumerConfig {
    @Value("${spring.kafka.bootstrap-servers}")
    private String bootstrapServers;

    @Bean
    public ConsumerFactory<String, KafkaMessage> consumerFactoryMessage()
    {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);           
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
        return new DefaultKafkaConsumerFactory<>(props, new StringDeserializer(),
                new JsonDeserializer<>(KafkaMessage.class));
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, KafkaMessage> kafkaListenerMessageContainerFactory()
    {
        ConcurrentKafkaListenerContainerFactory<String, KafkaMessage> factory = new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactoryMessage());
        return factory;
    }

    @Bean
    public ConsumerFactory<String, KafkaMessageWithAdditionalField> consumerFactoryMessageWithAdditionalField()
    {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
        return new DefaultKafkaConsumerFactory<>(props, new StringDeserializer(),
                new JsonDeserializer<>(KafkaMessageWithAdditionalField.class));
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, KafkaMessageWithAdditionalField> kafkaListenerMessageWithAdditionalFieldContainerFactory()
    {
        ConcurrentKafkaListenerContainerFactory<String, KafkaMessageWithAdditionalField> factory = new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactoryMessageWithAdditionalField());
        return factory;
    }
}

以下是听众：

    @KafkaListener(topicPartitions = @TopicPartition(partitions = "0", topic = "${foo.kafka.topic-springBoot}"), containerFactory = "kafkaListenerMessageContainerFactory")
    public void consumeSelf(@Headers Map<String, Object> map, KafkaMessage message, ConsumerRecord<String, Object> cr)
    {
        log.info("message received %s", message);
    }

    @KafkaListener(topicPartitions = @TopicPartition(partitions = "0", topic = "${foo.kafka.topic-springBoot}"), containerFactory = "kafkaListenerMessageWithAdditionalFieldContainerFactory")
    public void consumeSelfAdd(@Headers Map<String, Object> map, KafkaMessageWithAdditionalField message, ConsumerRecord<String, Object> cr)
    {
        log.info("messageKafkaMessageWithAdditionalField received %s", message);
    }

Answer 1

你不能那样做；您有 2 个不同的侦听器容器，其中的侦听器期望不同的对象。

对于接收不同类型的多个侦听器方法，您需要@KafkaListener在类级别和@KafkaHandler方法级别使用。

请参阅Class 上的 @KafkaListener。

在类级别使用@KafkaListener 时，您在方法级别指定@KafkaHandler。传递消息时，转换后的消息有效负载类型用于确定要调用的方法。

@KafkaListener(id = "multi", topics = "myTopic")
static class MultiListenerBean {

    @KafkaHandler
    public void listen(String foo) {
        ...
    }

    @KafkaHandler
    public void listen(Integer bar) {
        ...
    }

    @KafkaHandler(isDefault = true`)
    public void listenDefault(Object object) {
        ...
    }

}

默认方法是可选的，用于未知负载类型。

但这仅适用于智能解串器（知道如何转换为不同的有效负载）。

或者，您可以RecordFilterStrategy向侦听器容器工厂添加以跳过每个侦听器中的其他记录。