Spring Kafka：按顺序从两个不同的主题中读取

Question

Is it possible with Spring Kafka to read from two different topics in different consumers in a guaranteed order? For example, topic A stores information that is pertinent to determine how to handle the data that is stored in topic B. Topic A is read into memory and referenced, but needs to be completely populated before reading data in from topic B. Below is an example of what my current setup looks like...

@Service
public class TopicA {
  @KafkaListener(topics = "topicA")
  public void consume(ConsumerRecord<String, byte[]> record) {
    // ... some code here to populate an in-memory data structure
  }
}

@Service
public class TopicB {
  @KafkaListener(topics = "topicB")
  public void consume(ConsumerRecord<String, byte[]> record) {
    // ... some code here that depends on topic A having populated the in-memory data structure
  }
}

So far I've been leaning towards creating a Spring startup process (using @PostConstruct) that initializes the data structure by reading from topic A first, but have not been able to get that working. Does anyone have any suggestions? Thanks in advance!

Answer 1

@KafkaListener(id = "bConsumer" topics = "topicB", autoStartup = "false")

Then autowire the KafkaListenerEndpointRegistry bean and registry.getListenerContainer("bConsumer").start(); when you are ready.