Reactive Programming in Java: Mono and Flux with Spring Boot
Introduction
As we move towards reactive programming, concepts like Mono and Flux from Project Reactor (part of Spring WebFlux) become essential. They are core to building reactive applications that are non-blocking, handle large amounts of data efficiently, and work well with asynchronous processing. In this blog, we’ll break down Mono and Flux, their differences, and how you can use them in a simple Spring Boot project.
What is Reactive Programming?
Reactive programming is a paradigm that aims to provide better performance by being asynchronous, non-blocking, and event-driven. In traditional blocking systems, a request waits for the response, causing inefficiency when dealing with large-scale operations. Reactive systems handle events as they come, using non-blocking threads, which enables better performance under heavy loads.
Mono and Flux: The Basics
In reactive programming, everything is a stream of data that you can react to. Both Mono and Flux are Publisher types from Project Reactor, and they implement the Publisher interface from the Reactive Streams specification.
Mono
A Mono represents a stream with either zero or one item. It can complete with or without emitting an item, or it can fail with an error.
- Mono.just(“data”) — Emits one item.
