Consume String from Kafka Topic-CodePudding

I have a question regarding consuming JSON String from Kafka: Do I need to add a Config class for my consumer for Deserialization if I'm just consuming a String and then mapping it to a DTO?

@Service
public class Consumer   {

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


@Autowired
OBTMapper obtMapper;

@KafkaListener(topics = "foo" , groupId = "group_id")
public void receive(String message) {

    //Map String to DTO
    obtMapper.Mapper(message);
    logger.info("Message received %s", message);
    

}

When do I have to add this config class in general? I know that when I want to send an object I need to serialize it first in the Producer config and send it and then deserialize it in the consumer but do I also need that if I'm just producing a String and consuming it afterwards?

CodePudding user response：

Only binary data pass through Kafka, so yes, we must always serialize when producing and deserialize when consuming.

CodePudding user response：

You don't need to wire in your own ObjectMapper, but yes, you need a deserializer. Jackson ObjectMapper both deserializes string/bytes and parses that, though.

Spring Kafka natively offers JSON deserialization. Then you can use your POJO in the method parameter rather than just a String

https://docs.spring.io/spring-kafka/reference/html/#json-serde