1.3.6 Let's review

Think back on how you got to this point. In short, you’ve taken the following steps to build your Taco Cloud Spring application:

• You created an initial project structure using the Spring Initializr.
• You wrote a controller class to handle the home page request.
• You defined a view template to render the home page.
• You wrote a simple test class to prove your work.

Seems pretty straightforward, doesn’t it? With the exception of the first step to bootstrap the project, each action you’ve taken has been keenly focused on achieving the goal of producing a home page.

In fact, almost every line of code you’ve written is aimed toward that goal. Not counting Java import statements, I count only two lines of code in your controller class and no lines in the view template that are Spring-specific. And although the bulk of the test class utilizes Spring testing support, it seems a little less invasive in the context of a test.

That’s an important benefit of developing with Spring. You can focus on the code that meets the requirements of an application, rather than on satisfying the demands of a framework. Although you’ll no doubt need to write some framework-specific code from time to time, it’ll usually be only a small fraction of your codebase. As I said before, Spring (with Spring Boot) can be considered the frameworkless framework.

How does this even work? What is Spring doing behind the scenes to make sure your application needs are met? To understand what Spring is doing, let’s start by looking at the build specification.

In the pom.xml file, you declared a dependency on the Web and Thymeleaf starters. These two dependencies transitively brought in a handful of other dependencies, including the following:

• Spring’s MVC framework
• Embedded Tomcat
• Thymeleaf and the Thymeleaf layout dialect

It also brought Spring Boot’s autoconfiguration library along for the ride. When the application starts, Spring Boot autoconfiguration detects those libraries and automatically performs the following tasks:

• Configures the beans in the Spring application context to enable Spring MVC
• Configures the embedded Tomcat server in the Spring application context
• Configures a Thymeleaf view resolver for rendering Spring MVC views with Thymeleaf templates

In short, autoconfiguration does all the grunt work, leaving you to focus on writing code that implements your application functionality. That’s a pretty sweet arrangement, if you ask me!

Your Spring journey has just begun. The Taco Cloud application only touched on a small portion of what Spring has to offer. Before you take your next step, let’s survey the Spring landscape and see what landmarks you’ll encounter on your journey.