Working With Multi-Document Files

Spring Boot allows you to split a single physical file into multiple logical documents which are each added independently. Documents are processed in order, from top to bottom. Later documents can override the properties defined in earlier ones.

For application.yml files, the standard YAML multi-document syntax is used. Three consecutive hyphens represent the end of one document, and the start of the next.

For example, the following file has two logical documents:

spring:
  application:
    name: "MyApp"
---
spring:
  application:
    name: "MyCloudApp"
  config:
    activate:
      on-cloud-platform: "kubernetes"

For application.properties files a special #--- or !--- comment is used to mark the document splits:

spring.application.name=MyApp
#---
spring.application.name=MyCloudApp
spring.config.activate.on-cloud-platform=kubernetes

Property file separators must not have any leading whitespace and must have exactly three hyphen characters. The lines immediately before and after the separator must not be same comment prefix.

Multi-document property files are often used in conjunction with activation properties such as spring.config.activate.on-profile. See the next section for details.

Multi-document property files cannot be loaded by using the @PropertySource or @TestPropertySource annotations.