demo/src/main/resources/mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
    
    <settings>
        <setting name="useGeneratedKeys" value="true"/>
        <setting name="mapUnderscoreToCamelCase" value="true"></setting>
    </settings>

</configuration>