How Springboot does not need to compile again, automatic hot deployment

The first step is to introduce dependencies

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

 The second step is to set up the idea

ctl+alt+s open the idea configuration menu

the fourth step

ctrl+shift+alt+/ select Registry

Enter running, tick

Follow the above steps, ok