Comments on the Approach

The common way to create a new Spring Boot project has been to use Initializr, aka start.spring.io. The Spring CLI provides you with a command to interact with Initializr, see Initializr, but also offers other approaches to creating a new project and addresses the day-2 use case of adding code or configuration to an existing project.

The command boot new will let you create a new project from an existing one that lives in a source code repository. The boot new command lets you specify a small set of options to customize it to your needs, e.g., change the package name, but does not offer the selection of dependencies that you get with Initializr.

The approach of boot new is to clone an existing repository that contains fully working code and configuration in addition to your project’s dependencies. This approach makes it very easy for your or members of your team to create several project archetypes ,as they are just regular Spring projects in a source code repository that can be verified to work with a CI process. Refer to the section Creating New Projects for more information.

Then after initial project creation, you can add additional code and dependencies as needed using the boot add command. This command will intelligently merge an existing project into your current project. As with the boot new command, the existing project is a regular Spring project in a source code repository that can be compiled and verified to work with a CI process. Refer to the section Guide to "boot add" for more information.

Alternatively you can add additional code and dependencies by using user defined commands, which rely on using a template engine to create code and configuration. Refer to the sectionx ref:user-command-guide.adoc[Guide to user defined commands] for more information. The approach to using a template engine and making it easy for users to contribute commands that invoke those template was insipired from the project hygen

While both approaches to add additional code and dependencies have their use-cases, when creating a new project from scratch I’ve found it easier to start from working projects as not only do I get the approved dependencies that my company requires, but also code, configuration, and tests. It is a starting point that removes the busy work and uncertainty of selecting dependencies and cut-and-pasting code from a tutorial. Often those tutorial are so basic that they do not follow common best practice conventions, nor have any tests.

Creating a new project using templating can be a challenge. In my opinion, templating Java code for a new project is more difficult than cloning a new project from an existing working project. The cycle of creating a template, running the template, and then compiling the resulting generated project is brittle. However, I’ve found that creating smaller blocks of code and configuration are more amenable to the templating approach, e.g. spring controller new to add a controller to a current project, or spring feature new that adds a few files, such as classes annotated with @Controller, @Service, and @Repository.

Your experience may differ, but both types of code generation approaches are available in the Spring CLI.