Add dedicated Spring Boot documentation page

[lihaoyi]

The current spring-boot documentation page is hello-world level of detail, but given the importance of Spring Boot in the Java ecosystem (IIRC >80% market share among web frameworks) it deserves its own dedicate page in the Java section of the documentation. Similar to how Spark is important enough it gets its own dedicated page in the Scala section of the documentation

To start, we probably should have 5-6 example builds for spring boot, both to show off common configurations as well as to spend time discussing how common Spring Boot workflows using Maven/Gradle translate over to Mill: --watch, test, assembly or repackage, etc.. Perhaps even an example of auto-migration using ./mill init, or database migration using mill.contrib.flyway.

Someone interested in using Mill in a Spring Boot project should be able to have the docs walk them through several steps of working with and developing a spring boot application, so by the time the docs run out they already have a bunch of stuff learned and a bunch of code working they can build upon going forward

[lihaoyi]

@lefou do you think you could take a crack at this? IIRC you have worked with Mill and Spring Boot before

[lefou]

Let me look up if there are useful example projects on the Spring Boot doc site, for inspiration. The projects I work with aren't that straight forward. (One is just using the Spring DI container, which is a simple Java/Scala project, the other is a Vaadin Spring Boot App, which needs to shell out to some Maven process to get the Vaadin tooling right, maybe not the best Mill seller for now.)

[lefou]

• https://spring.io/guides/gs/spring-boot

  You will build a simple web application with Spring Boot and add some useful services to it.

• https://spring.io/guides/tutorials/spring-boot-kotlin

  This tutorial shows you how to build efficiently a sample blog application by combining the power of Spring Boot and Kotlin.

• https://spring.io/guides/tutorials/spring-boot-oauth2

  This guide shows you how to build a sample app doing various things with "social login" using OAuth 2.0 and Spring Boot.

[lefou]

• https://spring.io/guides/gs/relational-data-access

  You will build an application that uses Spring’s JdbcTemplate to access data stored in a relational database.

[lefou]

• https://spring.io/guides/gs/rest-service

  This guide walks you through the process of creating a “Hello, World” RESTful web service with Spring.

[lefou]

• https://github.com/com-lihaoyi/mill/discussions/5301