Enterprise Kotlin Handbook

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Spring Boot Web ​

Project sampling spring boot web. And some tricks with environment and profiles

Dependencies ​

  • java 17
  • kotlin 1.9
  • maven 3.9
  • spring-boot 3.2

How to build ​

bash
./mvnw compile package

How to test ​

bash
./mvnw test

How to run ​

Via maven plugin:

bash
./mvnw spring-boot:run

Running executable jar file:

bash
java -jar target/project-012-0.0.1-SNAPSHOT.jar

Run with another profile ​

You can pass the -Dspring.profiles.active=special to the jvm so spring will load the default application.properties AND the profile one:

bash
java -Dspring.profiles.active=special -jar target/project-012-0.0.1-SNAPSHOT.jar

Or pass the -Dspring-boot.run.profiles=special to maven:

bash
./mvnw spring-boot:run -Dspring-boot.run.profiles=special

This is useful to make your service environment aware.

Set profile and other properties using environment variable ​

Another option is to use an environment variable to change current profile. property values can be overridden in spring-boot using this strategy. The following override will work well on unix-like systems:

bash
SPRING_PROFILES_ACTIVE=special MY_MESSAGE="Hello to you!" java -jar target/project-012-0.0.1-SNAPSHOT.jar

It works with maven plugin as well:

bash
SPRING_PROFILES_ACTIVE=special MY_MESSAGE="Good day sir!" ./mvnw spring-boot:run

Environment variables are the preferred way to tweak configurations in production mode.

Noteworthy ​

  • This project was created using the spring initializr and a few properties added to pom.xml file.
  • Name your profiles with simple, meaningful names.
  • It is possible to load more than once extra profile, just provide a coma-separated list with their names.
  • It's possible to set active profiles from code, see the test cases.
  • As exercise, figure out how to make one extra profile get loaded by default.