利用jdbc做一个购买的事务

有一个在线交易电商平台，有两张表，分别是库存表和订单表，如下：

现在买家XiaoMing在该平台购买bag一个，需要同时在库存表中对bag库存记录减一，同时在订单表中生成该订单的相关记录。
请编写Java程序，实现XiaoMing购买bag逻辑。订单表ID字段为自增字段，无需赋值。

package chatroom;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.imageio.spi.IIOServiceProvider;

import org.apache.commons.dbcp2.BasicDataSource;

/**
 * @author 神余健芝
 * @date 创建时间：2017年5月20日 下午9:48:47
 */
public class JDBCTest {
    public static BasicDataSource ds = null;

    public final static String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    public final static String USER_NAME = "root";
    public final static String PASSWORD = "123456";
    public final static String DB_URL = "jdbc:mysql://localhost/shen_db?useUnicode=true&characterEncoding=utf-8&useSSL=false";

    public static void dbcpInit() {
        ds = new BasicDataSource();
        ds.setUrl(DB_URL);
        ds.setDriverClassName(JDBC_DRIVER);
        ds.setUsername(USER_NAME);
        ds.setPassword(PASSWORD);
    }

    public static void tranferAccount() throws ClassNotFoundException {
        Connection connection = null;
        PreparedStatement preparedStatement1 = null, preparedStatement2 = null;
        
        try {
            connection = ds.getConnection();
            System.out.println(connection);
            connection.setAutoCommit(false);
            preparedStatement1 = connection.prepareStatement("update inventory set Inventory= ? where ProductName= ?");
            preparedStatement1.setInt(1, 19);
            preparedStatement1.setString(2, "bag");
            preparedStatement1.execute();

            preparedStatement2 = connection.prepareStatement("insert into `Order` (buyer,ProductName) values(?,?)");
            preparedStatement2.setString(1, "XiaoMing");
            preparedStatement2.setString(2, "bag");
            preparedStatement2.execute();
            System.out.println(preparedStatement2);

            connection.commit();
        } catch (SQLException e) {
            if (connection != null)
                try {
                    connection.rollback();
                } catch (Exception e2) {
                    e2.printStackTrace();
                }
        } finally {
            try {
                if (connection != null)
                    connection.close();
                if (preparedStatement1 != null)
                    preparedStatement1.close();
                if (preparedStatement2 != null)
                    preparedStatement2.close();
            } catch (SQLException e2) {
                e2.printStackTrace();
            }
        }
    }

    public static void main(String[] args) throws ClassNotFoundException {
        dbcpInit();
        tranferAccount();
    }
}