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)

Creating a reactive file controller

With our reactive image service in place, we can start to work on the reactive file controller.

For starters, let's create a HomeController as shown here:

    public class HomeController { 
      private static final String BASE_PATH = "/images"; 
      private static final String FILENAME = "{filename:.+}"; 
      private final ImageService imageService; 
      public HomeController(ImageService imageService) { 
        this.imageService = imageService; 

The preceding code can be described as follows:

  • @Controller: This indicates that it is a web controller, and will be registered by Spring Boot to handle web requests.
  • BASE_PATH: This is a static string used to define the base of many routes.
  • FILENAME: This is a pattern for filenames where the "." is included. Otherwise, Spring...