Method Level @KafkaListener

Selection Criteria

Found method will be selected for further processing only if:

It has @KafkaListener annotation on one of its methods and has valid arguments.

Registration process

Operations registration process depends on @SendTo annotation usage.

With @SendTo

See Receive & Reply Operations

Without @SendTo

When listener is registered without @SendTo annotation, one-to-one operation will be created for each @KafkaListener annotation.

@Component
public class MultiMessagesListener {

    @KafkaListener(topics = {"messages.blue"})
    @KafkaListener(topics = {"messages.green", "messages.yellow"}, groupId = "group-id")
    public void listen(Object message) {}

}

The next operations will be created:

1. receive Object from messages.blue
2. receive Object from messages.green with groupId group-id
3. receive Object from messages.yellow with groupId group-id

When method will be ignored?

Here are the examples of methods which will be ignored:

Method with empty @KafkaListener annotation

This class will be ignored because it has empty @KafkaListener annotation.

@Component
public class MultiMessagesListener {

    @KafkaListener
    public void listen(Object message) {}

}