如何知道正在从列表中使用哪个kafka？

Question

I have a function for consuming Kafka. I consume multiple topics in the same function. But I don't know which topic is consumed

  @KafkaListener(topics = {"topic1","topic2"})
  public void kafkaConsume(String message) {
    //Print the kafka topic that is being consumed
    return;
  }

How do I print the kafka topic?

Answer 1

You can add @Headers parameter to get all the extra information you want within the message.

For example:

@KafkaListener(topics = "topicName")
public void listenWithHeaders(
   @Payload String message, 
   @Header(KafkaHeaders.TOPIC) String topic) {
       System.out.println("Received Message: " + message" + "from: " + topic);
}

You can get all this information in KafkaHeaders https://docs.spring.io/spring-kafka/api/org/springframework/kafka/support/KafkaHeaders.html

Or alternatively, you can consume a ConsumerRecord<K, V> which has most of the information as well

@KafkaListener(topics = "topicName")
public void listenConsumerRecord(ConsumerRecord<String, String> record) {
       System.out.println("Received Message: " + record.value() + "from: " + record.topic());
}