How to consume data from Apache Kafka in Spring Boot

Question

I have got the json using kafka-avro console-consumer . Now I want to get the json in a spring-boot console. What to do next?

Answer 1

You simply need to create a consumer:

@Service
public class Consumer {

    private final Logger logger = LoggerFactory.getLogger(Consumer.class);

    @KafkaListener(topics = "myTopic", groupId = "myTopic-consumer-group")
    public void consume(String message) throws IOException {
        logger.info(String.format("Message: %s", message));
    }
}

Answer 2

@KafkaListener annotation can be used to read messages from kafka topic.

Here is a working example of a class that reads Kafka messages:

import org.springframework.kafka.annotation.KafkaListener;

public class KafkaReader {

  private String latestMessage = "";

  @KafkaListener(topics = "${kafka.topic}")
  public void receive(String payload) {
      latestMessage = payload;
  }

  public String getLatestMessage() {
      System.out.println("Message read from topic: \n" + latestMessage);

      // Code to format the message

      return latestMessage.trim();
  }
}