JDBC获取数据库列名-关于 ResultSet 对象中列的类型和属性信息

public static void main(String[] args) {
        Connection connection = null;
        Statement statement = null;
        try {
            String url = "jdbc:postgresql://**:**/test";
            Class.forName("org.postgresql.Driver");
            connection= DriverManager.getConnection(url, "**", "**");
            String sql ="select * from table limit 2 offset 0";
            statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery(sql);
            convertList(resultSet);
            resultSet.close();
            statement.close();
            connection.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

private static List<Map<String, ?>> convertList(ResultSet rs) throws SQLException {
  List<Map<String, ?>>  list = new ArrayList<>();
  while (rs.next()) {
      ResultSetMetaData md = rs.getMetaData();//获取键名即列名
      int columnCount = md.getColumnCount();//获取列的数量
      Map<String, Object> orderedRecords = new LinkedHashMap<>();
      for (int i = 1; i <= columnCount; i++) {
      System.out.println(md.getColumnName(i) + "---" + rs.getObject(i));
      orderedRecords.put(md.getColumnName(i), rs instanceof BigInteger ? ((BigInteger) rs).longValue() : rs);
    }
  list.add(orderedRecords);
  }
  return list;
}