如何正确地循环和更新数据库中的数量。

import java.sql.*;

public class DatabaseUpdateExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, username, password);
             Statement stmt = conn.createStatement()) {

            String selectQuery = "SELECT * FROM mytable WHERE condition = 'some condition'";
            ResultSet resultSet = stmt.executeQuery(selectQuery);

            while (resultSet.next()) {
                int id = resultSet.getInt("id");
                int quantity = resultSet.getInt("quantity");

                // 根据需要进行更新操作，这里以增加数量为例
                int updatedQuantity = quantity + 1;

                String updateQuery = "UPDATE mytable SET quantity = " + updatedQuantity + " WHERE id = " + id;
                stmt.executeUpdate(updateQuery);
            }

            conn.commit();
            System.out.println("数据库中的数量已成功更新。");

        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}