https://stackoverflow.com/questions/45639904/intelijj-idea-springboot-devtools
spring boot实现不用重启就能动态编译修改的代码
This a guide I used some time ago to make it work: https://www.mkyong.com/spring-boot/intellij-idea-spring-boot-template-reload-is-not-working/
Basically you have two do 2 things:
Enable "Build project automatically" from Settings->Build, Execution, Deployment->CompilerGo to Registry(Ctrl+A, type "Registry") and enable compiler.automake.allow.when.app.running and ide.windowSystem.autoShowProcessPopup