Spring Kafka Producer/ Consumer

This project is a simple Spring Boot Kafka Producer application. It demonstrates how to integrate Apache Kafka with Spring Kafka, configure a producer, and publish messages to a Kafka topic. The producer sends JSON payloads to Kafka, which can then be consumed by a Kafka consumer (e.g., another Spring Boot app or CLI consumer).

It’s designed for beginners learning Kafka with Spring, covering:

• Kafka producer configuration
• Sending messages asynchronously & synchronously
• Serializing JSON messages
• Using REST endpoints to trigger Kafka message production

---

📋 Features

• Spring Boot 3 & Spring Kafka integration
• Kafka producer configuration
• Publish plain strings and JSON objects
• Expose REST endpoints to send messages
• Asynchronous message sending with callbacks

---

⚙️ Prerequisites

• Java 21+
• Maven or Gradle
• Docker (for running Kafka locally)
• Kafka broker (you can start one with Docker Compose)

Example Kafka setup with Docker Compose:

version: '3.8'
services:
  zookeeper:
    image: confluentinc/cp-zookeeper:7.6.1
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
  kafka:
    image: confluentinc/cp-kafka:7.6.1
    ports:
      - "9092:9092"
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://localhost:9092
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1