Reading from Kafka

The next step is to read individual raw messages from the Kafka topic, raw-messages. In Kafka jargon, a consumer is needed. In the last chapter, we used the command-line tools to write events to a topic and to read events back to the topic. This recipe shows how to write a Kafka consumer in Java using the Kafka library.

Getting ready

The execution of the previous recipes in this chapter is needed.

How to do it...

1. Create a file called Consumer.java in the src/main/java/doubloon/ directory with the following code:

package doubloon;

import java.util.Properties;

import org.apache.kafka.clients.consumer.ConsumerRecords;

public interface Consumer {
    public static Properties createConfig(String servers, String groupId) {
        Properties props = new Properties();
        props.put("bootstrap.servers", servers);
        props.put("group.id", groupId);
        props.put("enable.auto.commit", "true");
        props.put("auto.commit.interval.ms", "1000");
        props.put("auto...