Mybatis resultMap返回map

<resultMap type="Map" id="bankMaintainMap">
      <result column="bank_name" property="bankName"/>
      <result column="maintain_time_interval" property="maintainTimeInterval"/>
  </resultMap>
  <select id="getMaintainNotice" parameterType="Map" resultMap="bankMaintainMap">
      select 
          bank_name,
          maintain_time_interval
      from
          fp_channel_prd_bank
      where 
          channel_prd_id=7 
      and     
          maintain_time_interval
  </select>

public class DbUtils {
    private static String host = "47.93.******";
    private static String port = "3306";
    private static String username = "*****";
    private static String password = "******";
    private static String database = "******";
    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (Exception e) {
        }
    }
    private static Connection getConn() {
        Connection conn = null;
        try {
            String url = "jdbc:mysql://" + host + ":" + port + "/" + database;
            conn = DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return conn;
    }
    public static List<Map<String, Object>> execQuery(String sql, Object[] args) throws Exception {
        Connection conn = getConn();
        PreparedStatement ps = conn.prepareCall(sql);
        ResultSet rs = null;
        int count = StringUtils.countMatches(sql, "?");
        //变量赋值。。。。。。
        for (int i = 0; i < count; i++) {
            ps.setObject(i, args[i]);
        }
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
        rs = ps.executeQuery();
        ResultSetMetaData metaData = rs.getMetaData();
　　　　　　//注意。。metaData.getColumnName 获取字段名，rs.getObject 获取属性 是从 1 开始的，而不是从0 开始
        while (rs.next()) {
            int rowSize = metaData.getColumnCount();
            Map<String, Object> map = new HashMap<>();
            for (int i = 1; i <= rowSize; i++) {
                String labelName = metaData.getColumnName(i);
                Object obj = rs.getObject(labelName);
                map.put(labelName, obj);
            }
            list.add(map);
        }
        close(conn, ps, rs);
        return list;
    }
    /**
     * @param conn
     * @param ps
     * @param rs
     * @throws Exception
     */
    private static void close(Connection conn, PreparedStatement ps, ResultSet rs) throws Exception {
        rs.close();
        ps.close();
        conn.close();
    }