参考 https://docs.spring.io/spring-boot/docs/current/reference/html/appendix-configuration-metadata.html#configuration-metadata-additional-metadata

Spring Boot’s configuration file handling is quite flexible, and it is often the case that properties may exist that are not bound to a bean. You may also need to tune some attributes of an existing key. To support such cases and let you provide custom "hints", the annotation processor automatically merges items from into the main metadata file.@ConfigurationPropertiesMETA-INF/additional-spring-configuration-metadata.json

If you refer to a property that has been detected automatically, the description, default value, and deprecation information are overridden, if specified. If the manual property declaration is not identified in the current module, it is added as a new property.

The format of the file is exactly the same as the regular . The additional properties file is optional. If you do not have any additional properties, do not add the file.additional-spring-configuration-metadata.json spring-configuration-metadata.json

additional-spring-configuration-metadata.json 为手动添加， spring-configuration-metadata.json自动生成。additional-spring-configuration-metadata.json将会合并到spring-configuration-metadata.json中，并覆盖掉相同的说明。