Spring Boot Event-Driven Patterns

Spring Boot Event-Driven Patterns

Overview

Implement Event-Driven Architecture (EDA) patterns in Spring Boot 3.x using domain events, ApplicationEventPublisher, @TransactionalEventListener, and distributed messaging with Kafka and Spring Cloud Stream.

When to Use

• Implementing event-driven microservices with Kafka messaging
• Publishing domain events from aggregate roots in DDD architectures
• Setting up transactional event listeners that fire after database commits
• Adding async messaging with producers and consumers via Spring Kafka
• Ensuring reliable event delivery using the transactional outbox pattern
• Replacing synchronous calls with event-based communication between services

Quick Reference

Examples

Monolithic to Event-Driven Refactoring

Before (Anti-Pattern):

@Transactional
public Order processOrder(OrderRequest request) {
    Order order = orderRepository.save(request);
    inventoryService.reserve(order.getItems()); // Blocking
    paymentService.charge(order.getPayment()); // Blocking
    emailService.sendConfirmation(order); // Blocking
    return order;
}