Kafka Samples

Kafka Producer

When creating a Kafka Producer application client we need an object to represent the configuration properties of Kafka needed to start up a producer. Three properties are required:

• bootstrap.servers
• key.serializer
• value.serializer

Kafka Properties

bootstrap.servers - Cluster membership: partition leaders, etc.

key and value serializers - Classes used for message serialization and deserialization.

Example:

Properties props = new Properties();
properties.put("bootstrap.servers", "BROKER-1:9092", "BROKER-2:9093");
properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

For more configurations you can look at: http://kafka.apache.org/documentation/#producerconfigs

With these properties we can actually instantiate our Kafka object to with the basic required properties we've set above to an entry point in our application. An Example is below:

public static void main(String[] args){
    Properties props = new Properties();
    properties.put("bootstrap.servers", "BROKER-1:9092", "BROKER-2:9093");
    properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
    properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

    KafkaProducer myProducer = new KafkaProducer(props);
}

Producer Record

In order for our Kafka Producer to send messeges to Kakfa, it uses a Producer Record. A Producer Record only requires a minimum of two fields to be set which are:

• Topic - The topic to send messages to.
• Value - The message you want to send to the specified topic.

Example:

properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
ProducerRecord record = new ProducerRecord("my_topic", "My Message 1");