xml代码:

<select id="findMenuListByRole" resultType="java.util.Map" parameterType="java.util.List">
        select r.`name` as roleName,GROUP_CONCAT(distinct(m.`name`) SEPARATOR ' | ') as menuList
        from sys_role_menu as rm LEFT JOIN sys_role as r on rm.role_id=r.id LEFT JOIN sys_menu as m on rm.menu_id=m.id
        where m.name not like '功能菜单' and r.id in
        <foreach item="item" index="index" collection="list" open="(" separator="," close=")">
		  #{item}
	</foreach>
        GROUP BY r.`name`
    </select>

java代码:

public List<Map<String, String>> findMenuListByRole(List roleIDList);

需要注意的点:
1、resultType=”java.util.Map” 返回值类型
2、parameterType=”java.util.List” 输入的参数
3、将group的值拼接起来 GROUP_CONCAT(distinct(m.`name`) SEPARATOR ‘ | ‘) ;GROUP_CONCAT 有长度限制,group_concat_max_len
4、in的用法

<foreach item="item" index="index" collection="list" open="(" separator="," close=")">
		  #{item}
</foreach>

5、java代码是要注意

 List<Map<String, String>> 

而不单单是map
6、#相当于对数据 加上 双引号,$相当于直接显示数据