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)

Overriding property settings in production

Everytime we take our application to a new environment, there are always settings that have to be adjusted. We don't want to edit code. Instead, it's easier if we could just override various properties. And we can!

This was touched on briefly in Chapter 1, Quick Start with Java, under the guise of overriding Spring Boot's property settings. However, the fact that we can write our own custom configuration property beans makes this a powerful feature for application customization.

To recap the rules listed in Chapter 1, Quick Start with Java, property settings can be overridden in the following order, highest to lowest:

  1. @TestPropertySource annotations on test classes.
  2. Command-line arguments.
  3. Properties found inside SPRING_APPLICATION_JSON (inline JSON embedded in an env variable or system property).
  4. ServletConfig init parameters...