How to add multiple application.properties files in spring-boot?

Question

I have a Spring boot application that is divided in several modules. The main module runs the application and has an application.properties file in the resource

Answer 1

The problem is exactly what @geoand describes. Spring boot loads top level application.properties and ignores any properties file with the exact name located in other jars.

But I didn't find any concrete implementation on how to fix this problem, so here it is for those who wants to know the implementation.

Consider this project configuration:

+main_module
  +src
    +main
      +java
        +my/package/Application.java
      +resources/application.properties
+module_aa
  +src
    +main
      +java
        +my/package/config/ModuleAAConfig.java
      +resources/module_aa.properties
+module_bb
  +src
    +main
      +java
        +my/package/config/ModuleBBConfig.java
      +resources/module_bb.properties

Now to load properties for each sub modules correctly we need to add @PropertySource annotation on the configs of each module i.e ModuleAAConfig.java, ModuleBBConfig.java.

Example:

ModuleAAConfig.java

package my.package.config;

@Configuration
@PropertySource(
    ignoreResourceNotFound = false,
    value = "classpath:module_aa.properties")
public class ModuleAAConfig {}

ModuleBBConfig.java

package my.package.config;

@Configuration
@PropertySource(
    ignoreResourceNotFound = false,
    value = "classpath:module_bb.properties")
public class ModuleBBConfig {}

---

Bonus:

If you want to load profile specific property, you can do so by utilizing spring variables e.g.

@PropertySource("classpath:module_aa-${spring.profiles.active}.properties")