1 pom中添加 spring-boot-devtools 依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <optional>true</optional>
</dependency>

2 更改设置

选中 File->Setting –> Build, Execution, Deployment –> Compiler–>Build project automatically 

 

3  SHIFT+CTRL+A  输入 registry 在弹出的窗口中

　　找到compiler.automake.allow.when.app.running 打上勾

 

参考:

1 https://*.com/questions/33349456/how-to-make-auto-reload-with-spring-boot-on-idea-intellij

2 https://www.mkyong.com/spring-boot/intellij-idea-spring-boot-template-reload-is-not-working/