IM/src/main/resources/mapper/GroupsMapper.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.zhentao.groups.mapper.GroupsMapper">

    <resultMap id="BaseResultMap" type="com.zhentao.groups.pojo.Groupss">
            <id property="groupId" column="group_id" jdbcType="BIGINT"/>
            <result property="name" column="name" jdbcType="VARCHAR"/>
            <result property="creatorId" column="creator_id" jdbcType="BIGINT"/>
            <result property="avatar" column="avatar" jdbcType="VARCHAR"/>
            <result property="announcement" column="announcement" jdbcType="VARCHAR"/>
            <result property="description" column="description" jdbcType="VARCHAR"/>
            <result property="maxMembers" column="max_members" jdbcType="INTEGER"/>
            <result property="status" column="status" jdbcType="TINYINT"/>
            <result property="createdAt" column="created_at" jdbcType="TIMESTAMP"/>
            <result property="updatedAt" column="updated_at" jdbcType="TIMESTAMP"/>
    </resultMap>

    <sql id="Base_Column_List">
        group_id,name,creator_id,
        avatar,announcement,description,
        max_members,status,created_at,
        updated_at
    </sql>
</mapper>