1.导入包坐标

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

2.pom.xml添加piugins插件并打开开关

    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <version>2.2.2.RELEASE</version>
        <configuration>
          <fork>true</fork>
          <addResources>true</addResources>
        </configuration>
      </plugin>
    </plugins>

3.设置idea自动编译

File ->Settings ->Build, Execution, DeploymentAdvanced Setttings  ->  Compiler

4.Advanced Setttings设置

File ->Settings ->Advanced Setttings

5.重启IDEA