Book Image

Learning Spring Boot 2.0 - Second Edition

By : Greg L. Turnquist, Greg L. Turnquist
Book Image

Learning Spring Boot 2.0 - Second Edition

By: Greg L. Turnquist, Greg L. Turnquist

Overview of this book

Spring Boot provides a variety of features that address today's business needs along with today's scalable requirements. In this book, you will learn how to leverage powerful databases and Spring Boot's state-of-the-art WebFlux framework. This practical guide will help you get up and running with all the latest features of Spring Boot, especially the new Reactor-based toolkit. The book starts off by helping you build a simple app, then shows you how to bundle and deploy it to the cloud. From here, we take you through reactive programming, showing you how to interact with controllers and templates and handle data access. Once you're done, you can start writing unit tests, slice tests, embedded container tests, and even autoconfiguration tests. We go into detail about developer tools, AMQP messaging, WebSockets, security, and deployment. You will learn how to secure your application using both routes and method-based rules. By the end of the book, you'll have built a social media platform from which to apply the lessons you have learned to any problem. If you want a good understanding of building scalable applications using the core functionality of Spring Boot, this is the book for you.
Table of Contents (11 chapters)

Introducing Reactor types

We've mentioned Reactive Streams with little detail. There is a spec for Reactive Streams (, but it's important to understand that it is quite primitive. In fact, it's so primitive that it's not very effective for building applications. That may sound counterintuitive, but it wasn't written so much for end users as it was for framework developers. To build reactive applications, we'll use Project Reactor (, the core library that Spring Framework 5 uses for its reactive programming model.

To introduce Reactor's core types, we'll begin with the one we just saw in the previous section, Flux, and some code like this:

    Flux.just("alpha", "bravo", "charlie"); 

This simple creation of a Reactor Flux can be detailed as follows: