src/main/resources/mybatis/general/ContainerMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.huaheng.pc.general.container.mapper.ContainerMapper">
    <select id="getMaxCode" resultType="java.lang.String">
      SELECT code FROM container WHERE type = #{type}  ORDER BY id DESC LIMIT 1
    </select>
</mapper>