Spring Boot Backend Template

This is a Spring Boot backend template.

Features

• Database version control with Liquibase
• Automated API document generation with Springdoc
• Code formatting with Spotless
• Code quality checking with Sonarlint
• Commit message cheching with Commitlint

Requirements

• JDK (version 17 or later)
• MySQL

Quick start

Clone the repository.

$ git clone https://github.com/paakmau/spring-boot-backend-template

Navigate to project directory and run the Spring Boot application.

$ cd spring-boot-backend-template
$ ./gradlew bootRun

Enter http://localhost:8080/swagger-ui/index.html in the browser to access the document.

Document generation

https://github.com/springdoc/springdoc-openapi

Springdoc will scan the controller package, and automatically generate API document.

When the application is running, these URLs are available:

• Swagger UI endpoint
  http://localhost:8080/swagger-ui/index.html
• Swagger docs endpoint
  http://localhost:8080/v3/api-docs
• Swagger docs in yaml format endpoint
  http://localhost:8080/v3/api-docs.yaml

Multiple environments

This template configures dev and prod environments via Spring Boot profiles. The default profile is dev.

The application.yaml for test environment is placed alone.

Profiles can be specified like this:

$ ./gradlew bootRun --args='--spring.profiles.active=uat'

Database

H2 Database is used for dev and test. MySQL is used for prod.

Notice that the password of MySQL should not be saved in the repository. You need to set the password of root user in the MYSQL_ROOT_PASSWORD environment variable to access to MySQL database.

Version control

https://github.com/liquibase/liquibase
https://github.com/liquibase/liquibase-gradle-plugin
https://github.com/liquibase/liquibase-hibernate

The changelog file is the db.changelog-master.yaml in the resources/db/changelog directory.

You can use Liquibase Gradle plugin to maintain the changelog. To modify the database structure, you should follow this workflow:

1. Edit entities in the entity package
2. Run the diffChangelog Gradle task
3. Check if the modified db.changelog-master.yaml does what you want, edit it if not
4. Run this application, the database will be synced by Liquibase

Exception handling

Exception classes should be put in the exception package. And use the @ResponseStatus annotation to specify the HTTP status code.

Code formatting

https://github.com/diffplug/spotless.

Check the style

You can check format violations by runing the spotlessCheck Gradle task.

$ ./gradlew spotlessCheck

Apply the style

If there are violations, run the spotlessApply Gradle task to perform formatting.

$ ./gradlew spotlessApply

VS Code integration

You can install the Spotless Gradle extension to lint and format your code.

Code quality checking

https://remal.gitlab.io/gradle-plugins/plugins/name.remal.sonarlint/.

Check main

Check Java source files in the main directory.

$ ./gradlew sonarlintMain

Check test

Check Java source files in the test directory.

$ ./gradlew sonarlintTest

VS Code integration

Install the SonarLint extension to lint your code.

Commit message checking

https://github.com/NetrisTV/gradle-commitlint-plugin

Pass a commit message to Commitlint Gradle plugin, the plugin will lint it against Conventional Commits rules.

This plugin should be used with Git Hook

Git hook

https://github.com/STAR-ZERO/gradle-githook

There are some hooks configured in this template:

Hook	Gradle task
pre-commit	spotlessCheck
pre-commit	sonarlintMain
pre-commit	sonarlintTest
commit-msg	commitlint

Deployment

The project can be build as a Docker image.

Run the bootJar task to build a .jar file. Notice the build task should not be used.

$ ./gradlew bootJar

A demo-0.0.1-SNAPSHOT.jar file will be found in the build/libs folder. Now you can use the Dockerfile to build an image.

$ docker build -t demo:0.0.1-SNAPSHOT .

Besides the docker build command, you can also use Buildah.

$ buildah bud -t demo:0.0.1-SNAPSHOT

In addition, the image can be exported as follows.

$ docker save -o demo-0.0.1-SNAPSHOT.tar demo:0.0.1-SNAPSHOT

The command should like this if built with Buildah.

$ buildah push demo:0.0.1-SNAPSHOT docker-archive:./demo-0.0.1-SNAPSHOT.tar:demo:0.0.1-SNAPSHOT