Mybatis的resultMap返回map问题

<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();
    }