mybatis多表查询返回map类型

mybatis进行多表查询时，返回的结果为map而不是某个实体类的时候，如下：

<!-- 查询多表返回类型为map -->
<select id="list" parameterType="User" resultType="map">
    SELECT
        u.uid,
        u.role_id,
        m.mid,
        m.mname,
        r.role_id,
        r.mid,
        r.iden
    FROM
        user u
    LEFT JOIN role r ON u.role_id = r.role_id
    LEFT JOIN module m ON r.mid = m.mid
    WHERE
        u.uid = #{uid}
</select>

DAO中的成员方法：

public List<Map<String, Object>> list(User user, "findListMap");

对返回的List

@Test
public void listMap() {
    User user = new User();
    user.setUid(1);
    List<Map<String, Object>> listMap = testService.listMap(user, "findListMap");
    for (Map<String, Object> map : listMap) {
        Set<String> set = map.keySet();
        Iterator<String> it = set.iterator();
        while (it.hasNext()) {
            Object key = it.next();
            Object value = map.get(key);
            System.out.println(value);
       }
    }
}

参考：
http://blog.csdn.net/cydbetter/article/details/79074064
https://blog.csdn.net/lxxxzzl/article/details/43604481
https://blog.csdn.net/GensingU/article/details/74856351
https://blog.csdn.net/chenluyao_it/article/details/78747859