如何在DTO中对数据库中的数据进行分组？

// 定义DTO类
public class GroupDTO {
    private String groupField;
    private int count;

    // 省略getter和setter方法
}

// 在DAO层进行查询和分组
public List<GroupDTO> getGroupedData() {
    String sql = "SELECT group_field, COUNT(*) AS count FROM table_name GROUP BY group_field";
    List<GroupDTO> resultList = new ArrayList<>();

    try (Connection conn = getConnection();
         Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery(sql)) {

        while (rs.next()) {
            GroupDTO dto = new GroupDTO();
            dto.setGroupField(rs.getString("group_field"));
            dto.setCount(rs.getInt("count"));
            resultList.add(dto);
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }

    return resultList;
}