java - How to externalize application.properties in Tomcat webserver for Spring?

Question

SpringApplication will load properties from application.properties files in the following locations and add them to the Spring Environment:

- A /config subdirectory of the current directory.
- The current directory
- A classpath /config package
- The classpath root

The list is ordered by precedence (properties defined in locations higher in the list override those defined in lower locations).

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html#boot-features-external-config-application-property-files

Question: when running a war file on a tomcat server: how can I add an additional location for the application.properties outside the classpath or the tomcat container, like d:application.properties?

The custom location should get highest precedence regarding the locations above.

Problem is: I could of course add a /config folder inside my exploded war in the tomcat webapps folder, but then I'd lose any custom configuration if the webapps folder is cleaned and war is redeployed.

Thus I'd like to add an additional location outside.

Answer 1

For me the easiest way to do it, was to place a context file inside Tomcat's config folder. For example if your application is running under root path (eg. http://your_domain.com/) you need to create a file [path_to_your_tomcat]/conf/Catalina/localhost/ROOT.xml. If your application runs in a different path, for example http://your_domain.com/example_path the file should be named like this [path_to_your_tomcat]/conf/Catalina/localhost/example_path.xml. Inside this file you can specify a path to the external application.properties file that can be placed anywhere on your hard drive.

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <Environment name="spring.config.location" value="file:/path/to/your/application/properties/file/" type="java.lang.String"/>
</Context>