Record a problem when IDEA creates a new Springboot project to load external configuration and the final solution that I don't understand

need:

To create a new springboot project using Idea, you need to use an external configuration file.

The overall directory structure is as follows:

Spring Boot启动会扫描以下位置的application.properties或者application.yml文件作为spring boot的默认配置文件
-file:/config/
-file:./
-classpath: