第一步：在实体类中添加字段sortMap

public class Admin {
    //......
    private Map<String,String> sortMap;  //排序
}

 第二步：在映射文件中添加如下代码

<select id="selectByCondition" resultMap="BaseResultMap" parameterType="Admin">
    select *
    from db_rbac.tb_admin
    order by
    <foreach item="value" index="key" collection="sortMap.entrySet()" separator=",">
        ${key} ${value}
    </foreach>
</select>

第三步：测试代码

HashMap<String, String> map = new HashMap<>();
map.put("name", "asc");
map.put("age","desc");
admin.setSortMap(map);