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

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 resources folder. I'm wondering if I can add another properties file in a submodule to separate properties that are belonging to that module and how to make this working (because it is not).

+main_module
  +src
    +main
      +java
        +my/package/Application.java
        +resources/application.properties
+support_module
  +src
    +main
      +java
        +resources/application.properties

So, this is the current situation. Clearly the properties file in the module support_module is not read causing a NoSuchBeanDefinitionException, while if I put the content in the other properties file everything works fine.

What you are trying to do will not work when using Maven or Gradle. The reason is that when the artifact (jar most likely since you are using Spring Boot) is created, there will only be one application.properties file in the root.

I suggest you either change the name of the properties file on the support module and then configure Spring Boot to look for that file as well (take a look at this or this answer for pointers), or use some kind of merging task for your build tool (something like this perhaps)

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")

You can also refer to an explicit location using the spring.config.location environment property (comma-separated list of directory locations, or file paths)

$ java -jar myproject.jar --spring.config.location=classpath:/default.properties,classpath:/override.properties

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