@kafkalistener未使用消息-反序列化问题

Question

@Component
public static class PageViewEventSource implements ApplicationRunner {

private final MessageChannel pageViewsOut;
private final Log log = LogFactory.getLog(getClass());

public PageViewEventSource(AnalyticsBinding binding) {
    this.pageViewsOut = binding.pageViewsOut();
}

@Override
public void run(ApplicationArguments args) throws Exception {
    List<String> names = Arrays.asList("priya", "dyser", "Ray", "Mark", "Oman", "Larry");
    List<String> pages = Arrays.asList("blog", "facebook", "instagram", "news", "youtube", "about");
    Runnable runnable = () -> {
        String rPage = pages.get(new Random().nextInt(pages.size()));
        String rName = pages.get(new Random().nextInt(names.size()));
        PageViewEvent pageViewEvent = new PageViewEvent(rName, rPage, Math.random() > .5 ? 10 : 1000);


        Serializer<PageViewEvent> serializer = new JsonSerde<>(PageViewEvent.class).serializer();
        byte[] m = serializer.serialize(null, pageViewEvent);

        Message<byte[]> message =  MessageBuilder
                .withPayload(m).build();

        try {
            this.pageViewsOut.send(message);
            log.info("sent " + message);
        } catch (Exception e) {
            log.error(e);
        }
    };
    Executors.newScheduledThreadPool(1).scheduleAtFixedRate(runnable, 1, 1, TimeUnit.SECONDS);
}

我试图通过Spring KafkaListener在单独的消费者应用程序中使用这些消息

@Service
public class PriceEventConsumer {


private static final Logger LOG = LoggerFactory.getLogger(PriceEventConsumer.class);

@KafkaListener(topics = "test1" , groupId = "json", containerFactory = "kafkaListenerContainerFactory")
public void receive(Bytes data){
//public void receive(@Payload PageViewEvent data,@Headers MessageHeaders headers) {
    LOG.info("Message received");
    LOG.info("received data='{}'", data);

    }

集装箱工厂配置

 @Bean
 public ConsumerFactory<String, Bytes> consumerFactory() {

  Map<String, Object> props = new HashMap<>();
  props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
  props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
  StringDeserializer.class);
   props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, 
  BytesDeserializer.class);
  props.put(ConsumerConfig.GROUP_ID_CONFIG, "json");
  props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");

  return new DefaultKafkaConsumerFactory<>(props);

 }

 @Bean
 public ConcurrentKafkaListenerContainerFactory<String, Bytes> 

 kafkaListenerContainerFactory() {

  ConcurrentKafkaListenerContainerFactory<String, Bytes> factory =
        new ConcurrentKafkaListenerContainerFactory<>();
  factory.setConsumerFactory(consumerFactory());
  return factory;
 }

在这种配置下，使用者不接收消息（字节）。如果我将Kafka侦听器更改为接受字符串，则会出现以下异常：

   @KafkaListener(topics = "test1" , groupId = "json", containerFactory = "kafkaListenerContainerFactory")

 public void receive(String data){

    LOG.info("Message received");
    LOG.info("received data='{}'", data);

    }

  @KafkaListener(topics = "test1" , groupId = "json", containerFactory = "kafkaListenerContainerFactory")

  public void receive(@Payload PageViewEvent data,@Headers MessageHeaders headers) {
    LOG.info("Message received");
    LOG.info("received data='{}'", data);

   }

集装箱工厂配置

 @Bean
 public ConsumerFactory<String,PageViewEvent > priceEventConsumerFactory() {

    Map<String, Object> props = new HashMap<>();
    props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
    props.put(ConsumerConfig.GROUP_ID_CONFIG, "json");
    props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
    return new DefaultKafkaConsumerFactory<>(props, new StringDeserializer(), new JsonDeserializer<>(PageViewEvent.class));



}

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, PageViewEvent> priceEventsKafkaListenerContainerFactory() {
      ConcurrentKafkaListenerContainerFactory<String, PageViewEvent> factory =
            new ConcurrentKafkaListenerContainerFactory<>();
     factory.setConsumerFactory(priceEventConsumerFactory());
     return factory;
     }

制片人-

  @Override
  public void run(ApplicationArguments args) throws Exception {
  List<String> names = Arrays.asList("priya", "dyser", "Ray", "Mark", "Oman", "Larry");
   List<String> pages = Arrays.asList("blog", "facebook", "instagram", "news", "youtube", "about");
   Runnable runnable = () -> {
    String rPage = pages.get(new Random().nextInt(pages.size()));
    String rName = pages.get(new Random().nextInt(names.size()));
    PageViewEvent pageViewEvent = new PageViewEvent(rName, rPage, Math.random() > .5 ? 10 : 1000);

    Message<PageViewEvent> message =  MessageBuilder
            .withPayload(pageViewEvent).build();
                    try {
        this.pageViewsOut.send(message);
        log.info("sent " + message);
    } catch (Exception e) {
        log.error(e);
    }
};

Answer 1

对于<2.2.x版本，可以使用MessageConverter将记录从kfka反序列化为POJO

从版本2.2开始，您可以显式地配置反序列化程序，使用提供的目标类型并忽略标头中的类型信息，方法是使用一个重载的构造函数，该构造函数具有一个布尔值

@Bean
public ConsumerFactory<String,PageViewEvent > priceEventConsumerFactory() {

Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
props.put(ConsumerConfig.GROUP_ID_CONFIG, "json");
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
return new DefaultKafkaConsumerFactory<>(props, new StringDeserializer(), new JsonDeserializer<>(PageViewEvent.class,false));

}

或使用MessageConverter

 @Bean
 public ConcurrentKafkaListenerContainerFactory<String, Bytes> kafkaListenerContainerFactory() {

 ConcurrentKafkaListenerContainerFactory<String, Bytes> factory =
    new ConcurrentKafkaListenerContainerFactory<>();
 factory.setConsumerFactory(consumerFactory());
 factory.setMessageConverter(new StringJsonMessageConverter());
 return factory;
}