Producer API basics in Kafka - Mini Project: Build & Apply

Producer API basics

📖 Scenario: You are working on a simple messaging system where you need to send messages to a Kafka topic. This is common in real-world applications like logging systems, event tracking, or communication between services.

🎯 Goal: Build a Kafka producer that sends a few messages to a specific Kafka topic using the Producer API basics.

📋 What You'll Learn

Create a Kafka producer with the correct configuration

Send messages to a Kafka topic named test-topic

Use a loop to send multiple messages

Print confirmation after sending each message

💡 Why This Matters

🌍 Real World

Kafka producers are used in many real-world systems to send data streams like logs, user activity, or sensor data to other services for processing.

💼 Career

Understanding Kafka producer basics is essential for roles in backend development, data engineering, and real-time data processing.

1

Create Kafka producer configuration

Create a Properties object called props and set the following properties exactly: bootstrap.servers to localhost:9092, key.serializer to org.apache.kafka.common.serialization.StringSerializer, and value.serializer to org.apache.kafka.common.serialization.StringSerializer.

Kafka

# Your code here

Need a hint?

Use props.put(key, value) to set each configuration property.

2

Create Kafka producer instance

Create a KafkaProducer<String, String> object called producer using the props configuration.

Kafka

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
// Your code here

Need a hint?

Use new KafkaProducer<>(props) to create the producer.

3

Send messages to the topic

Use a for loop with an integer variable i from 1 to 3 inclusive. Inside the loop, send a message to the topic test-topic with the value "Message " + i using producer.send() and a ProducerRecord<String, String>. Use i as the key.

Kafka

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
KafkaProducer producer = new KafkaProducer(props);
// Your code here

Need a hint?

Use new ProducerRecord<>(topic, key, value) inside producer.send().

4

Print confirmation after sending

Inside the for loop, after sending each message, print "Sent message: Message " + i. After the loop, close the producer using producer.close().

Kafka

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
KafkaProducer producer = new KafkaProducer(props);
for (int i = 1; i ("test-topic", Integer.toString(i), "Message " + i));
    // Your code here
}
// Your code here

Need a hint?

Use System.out.println() inside the loop and producer.close() after the loop.