Java applications that are using Spring Boot have configuration their configuration in the application.yml and/or bootstrap.yml files. These files are packaged in the JAR file so the user cannot change them.
There are various ways how these values can be overridden in Spring Boot (external YML file, environment variables, Java System properties).
The Java System properties are a common way how to provide external configuration options. They are defined using -D options for Java. Java System properties can override any configuration.
The values for Java System properties can be defined in STDENV member of JZOS Batch Launcher for Java started tasks on z/OS.
When your run the sample application on your computer using gradlew bootRun it is using external configuration file config/local/application.yml. This file contains the value for running on your computer in development mode.
Let's say that we want to use port 10081 instead of default 10080. This is set by property server.port.
Running from JAR:
java -Dserver.port=10081 -jar build/libs/*.jar --spring.config.additional-location=file:./config/local/application.yml
Running by Gradle:
./gradlew bootRun --args='--spring.config.additional-location=file:./config/local/application.yml --server.port=10081'
- Extension is
.yml - Indentation is 4 spaces
- Property names are using
camelCase - The
application.ymlbundled into the JAR should contain only valid or typical values for any deployment (ie. it should not contain values that are correct only on your computer)
- Intro to Spring YML configuration - http://www.baeldung.com/spring-yaml
- Full reference - https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html
- For advanced use case of sharing a common YML file - http://roufid.com/load-multiple-configuration-files-different-directories-spring-boot/