Kafka — Hello Producer

In this example, we’ll make the use of Confluent Kafka to publish some messages on Kafka. In this example, we’ll use kafka-clients to talk to Confluent Kafka Server. Once the messages are published we’ll consume those meesage.

Create Topic

`kafka-topics — create — bootstrap-server localhost:9092 — replication-factor 1 — partitions 1 — topic hello-producer-topic`

Check Data —

`kafka-console-consumer — bootstrap-server localhost:9092 — topic hello-producer-topic — from-beginning`

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.kafka.examples</groupId>
    <artifactId>hello-producer</artifactId>
    <version>2.3.0</version>

    <properties>
        <java.version>1.8</java.version>
        <kafka.version>2.3.0</kafka.version>
    </properties>

    <build>
        <plugins>
            <!-- Maven Compiler Plugin-->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <!-- Apache Kafka Clients-->
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka-clients</artifactId>
            <version>${kafka.version}</version>
        </dependency>

        <!-- Apache Log4J2 binding for SLF4J -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-slf4j-impl</artifactId>
            <version>2.11.0</version>
        </dependency>
    </dependencies>
</project>

AppConfig.java

class AppConfigs {
    final static String applicationID = "HelloProducer";
    final static String bootstrapServers = "localhost:9092";
    final static String topicName = "hello-producer-topic";
    final static int numEvents = 100;
}

HelloProducer.java

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.IntegerSerializer;
import org.apache.kafka.common.serialization.StringSerializer;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.Properties;

public class HelloProducer {
    private static final Logger logger = LogManager.getLogger();

    public static void main(String[] args) {

        logger.info("Creating Kafka Producer...");
        Properties props = new Properties();
        props.put(ProducerConfig.CLIENT_ID_CONFIG, AppConfigs.applicationID);
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, AppConfigs.bootstrapServers);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class.getName());
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());

        KafkaProducer<Integer, String> producer = new KafkaProducer<>(props);

        logger.info("Start sending messages...");
        for (int i = 1; i <= AppConfigs.numEvents; i++) {
            producer.send(new ProducerRecord<>(AppConfigs.topicName, i, "Simple Message-" + i));
        }

        logger.info("Finished - Closing Kafka Producer.");
        producer.close();

    }
}

Run the MainApp and then you can check data like below —