用JSP和数据库做的购物车的源程序

下面是我用JSP和数据库做的购物车的源程序：

//shop_cart.jsp ＜%@ page contentType="text/html;charset=gb2312"%＞ ＜%@ page session="true" %＞ ＜%@ page language="java" import="java.sql.*" %＞ ＜jsp:useBean id="bka" scope="page" class="shop.bka" /＞ ＜% String product_type; String action; int product_id; int curpage; //商品类型 if (request.getParameter("product_type")==null){ product_type="all"; }else{ product_type=request.getParameter("product_type"); } //页数和商品类型参数，可以在“继续购物”时返回到上次购物的页面 if (request.getParameter("curpage")==null){ curpage=1; }else{ curpage=java.lang.Integer.parseInt(request.getParameter("curpage")); } //动作 if (request.getParameter("action")==null){ action="view"; }else{ action=request.getParameter("action"); } //商品编号 if (request.getParameter("product_id")==null){ product_id=0; }else{ product_id=java.lang.Integer.parseInt(request.getParameter("product_id")); } int bbb; bbb=1; Integer num = new Integer(bbb); //商店编号 session.putValue("shop_id",num); //顾客username session.putValue("guest_name","asp2001"); String guest_name=(String)session.getValue("guest_name"); Integer shop_id=(Integer)session.getValue("shop_id"); java.lang.String sql; java.sql.ResultSet rs; if (action.compareTo("add")==0) { sql="select cart_quantity from shop_cart where cart_shop_id=" + shop_id + " and cart_guest_id='" + guest_name + "' and cart_product_id=" + product_id ; rs = bka.executeQuery(sql); if (rs.next()){ int cart_quantity; cart_quantity=java.lang.Integer.parseInt(rs.getString("cart_quantity"))+1; sql="update shop_cart set cart_quantity=" + cart_quantity + " where cart_shop_id=" + shop_id + " and cart_guest_id='" + guest_name + "' and cart_product_id=" + product_id ; rs = bka.executeQuery(sql);} else { sql="insert into shop_cart (cart_shop_id,cart_guest_id, cart_product_id,cart_quantity) values ('" + shop_id + "','" + guest_name + "','" + product_id + "',1)"; rs = bka.executeQuery(sql); } } if (action.compareTo("clear")==0) { sql="delete from shop_cart where cart_shop_id=" + shop_id + " and cart_guest_id='" + guest_name + "'"; rs = bka.executeQuery(sql); } if (action.compareTo("delete")==0) { sql="delete from shop_cart where cart_shop_id=" + shop_id + " and cart_guest_id='" + guest_name + "' and cart_product_id=" + product_id ; rs = bka.executeQuery(sql); } %＞ ＜div align="center"＞＜center＞ ＜table border="0" cellpadding="0" cellspacing="0" width="610" height="2"＞ ＜tr＞ ＜td＞＜form method="POST" action="shop_cart.jsp?action=update;product_type=＜%=product_type%＞;curp age=＜%=curpage%＞"＞ ＜table border="0" cellpadding="0" cellspacing="0" width="610" height="2"＞ ＜tr＞ ＜td width="122" height="7"＞＜div align="center"＞＜center＞＜table border="1" cellpadding="2" cellspacing="0" width="100%" bordercolorlight="#FFB468" bordercolordark="#FFFFFF" bgcolor="#FFB468"＞ ＜tr＞ ＜td width="100%"＞＜div align="center"＞＜center＞＜p＞购物车＜/td＞ ＜/tr＞ ＜/table＞ ＜/center＞＜/div＞＜/td＞ ＜td width="122" height="7" style="border: medium" align="center"＞＜div align="center"＞＜center＞＜table border="1" cellpadding="2" cellspacing="0" width="100%" bordercolorlight="#FFB468" bordercolordark="#FFFFFF" bgcolor="#FFB468"＞ ＜tr＞ ＜td width="100%"＞＜div align="center"＞＜center＞＜p＞＜a href="shop_list.jsp?shop_id=＜%=shop_id%＞;product_type=＜%=product_type%＞ ;curpage=＜%=curpage%＞"＞继续购物＜/a＞＜/td＞ ＜/tr＞ ＜/table＞ ＜/center＞＜/div＞＜/td＞ ＜td width="122" height="7" style="border: medium" align="center"＞＜div align="center"＞＜center＞＜table border="1" cellpadding="2" cellspacing="0" width="100%" bordercolorlight="#FFB468" bordercolordark="#FFFFFF" bgcolor="#FFB468"＞ ＜tr＞ ＜td width="100%"＞＜div align="center"＞＜center＞＜p＞＜a href="javascript: document.forms[0].submit()"＞重新计费＜/a＞＜/td＞ ＜/tr＞ ＜/table＞ ＜/center＞＜/div＞＜/td＞ ＜td width="122" height="7" style="border: medium" align="center"＞＜div align="center"＞＜center＞＜table border="1" cellpadding="2" cellspacing="0" width="100%" bordercolorlight="#FFB468" bordercolordark="#FFFFFF" bgcolor="#FFB468"＞ ＜tr＞ ＜td width="100%"＞＜div align="center"＞＜center＞＜p＞ ＜a href="shop_cart.jsp?action=clear;product_type=＜%=product_type%＞;curpage= ＜%=curpage%＞"＞清空购物车＜/a＞＜/td＞ ＜/tr＞ ＜/table＞ ＜/center＞＜/div＞＜/td＞ ＜td width="122" height="7" style="border: medium" align="center"＞ ＜div align="center"＞＜center＞＜table border="1" cellpadding="2" cellspacing="0" width="100%" bordercolorlight="#FFB468" bordercolordark="#FFFFFF" bgcolor="#FFB468"＞ ＜tr＞ ＜td width="100%"＞＜div align="center"＞＜center＞＜p＞ ＜a href="shop_order.asp"＞确认购买＜/a＞＜/td＞ ＜/tr＞ ＜/table＞ ＜/center＞＜/div＞＜/td＞ ＜/tr＞ ＜tr align="center"＞ ＜td width="610" height="1" colspan="5"＞＜div align="center"＞＜center＞ ＜table border="1" cellpadding="2" cellspacing="0" width="100%" bgcolor="#FDFEE2" bordercolorlight="#FFB468" bordercolordark="#FFFFFF" height="40"＞ ＜tr＞ ＜td width="20%" height="8" align="left"＞商品名称＜/td＞ ＜td width="10%" height="8" align="left"＞市场价＜/td＞ ＜td width="10%" height="8" align="left"＞优惠价＜/td＞ ＜td width="10%" height="8" align="left"＞数量＜/td＞ ＜td width="14%" height="8" align="left"＞小计＜/td＞ ＜td width="12%" height="8" align="left"＞定金比例＜/td＞ ＜td width="17%" height="8" align="left"＞定金小计＜/td＞ ＜td width="17%" height="8" align="left"＞删除＜/td＞ ＜/tr＞ ＜% sql="select shop_product.product_id,shop_product.product_name, shop_product.product_price,shop_product.product_discount, shop_cart.cart_quantity,shop_product.product_first from shop_cart, shop_product where shop_cart.cart_shop_id=" + shop_id + " and shop_cart.cart_guest_id='" + guest_name + "' and shop_cart.cart_product_id=shop_product.product_id"; rs = bka.executeQuery(sql); int total; int total_first; total=0; total_first=0; String product_name; int product_price; int product_discount; int product_first; int cart_quantity; if (rs.next()){ while (rs.next()) { product_id=java.lang.Integer.parseInt(rs.getString(1)); product_name=rs.getString(2); product_price=java.lang.Integer.parseInt(rs.getString(3)); product_discount=java.lang.Integer.parseInt(rs.getString(4)); cart_quantity=java.lang.Integer.parseInt(rs.getString(5)); product_first=java.lang.Integer.parseInt(rs.getString(6)); %＞ ＜tr＞ ＜td width="10%" height="1" align="left"＞＜%=product_name%＞＜/td＞ ＜td width="10%" height="1" align="left"＞＜%=product_price%＞＜/td＞ ＜td width="10%" height="1" align="left"＞＜%=product_discount%＞＜/td＞ ＜td width="10%" height="1" align="left"＞ ＜input type="text" name="＜%= "t" + product_id %＞" size="3" value="＜%=cart_quantity%＞"＞＜/td＞ ＜td width="14%" height="1" align="left"＞ ＜%=product_discount*cart_quantity%＞＜/td＞ ＜td width="12%" height="1" align="left"＞＜%=product_first + "%"%＞＜/td＞ ＜td width="17%" height="1" align="left"＞ ＜%=product_first*product_discount*cart_quantity/100.0%＞＜/td＞ ＜td width="17%" height="1"＞＜div align="center"＞＜center＞＜p＞ ＜a href="shop_cart.jsp?action=delete;product_id=＜%=product_id%＞"＞ delete＜/a＞＜/td＞ ＜/tr＞ ＜% total=total+product_discount*cart_quantity; total_first=total_first+product_discount*cart_quantity*product_first/100; } %＞ ＜tr align="center"＞ ＜td width="72%" colspan="6" height="16"＞＜div align="right"＞＜p＞总计＜/td＞ ＜td width="36%" colspan="2" height="16"＞＜div align="left"＞＜%=total%＞＜/td＞ ＜/tr＞ ＜tr align="center"＞ ＜td width="72%" colspan="6" height="16"＞＜div align="right"＞＜p＞定金总计＜/td＞ ＜td width="36%" colspan="2" height="16"＞＜div align="left"＞＜%=total_first%＞＜/td＞ ＜/tr＞ ＜tr align="center"＞ ＜td width="72%" colspan="6" height="16"＞＜div align="right"＞ ＜p＞结余＜/td＞ ＜td width="36%" colspan="2" height="16"＞＜div align="left"＞ ＜%=total-total_first%＞＜/td＞ ＜/tr＞ ＜/table＞ ＜/center＞＜/div＞ ＜% }else{ %＞ ＜p align="center"＞购物车为空!＜/p＞ ＜% } %＞

数据库操作部分

程序用到两个表：
1 shop_cart表
cart_id int 购物车编号 自动编号
cart_shop_id nvarchar 商店编号
cart_product_id nvarchar 商品编号
cart_quantity int 商品数量
临时存放购物车数据

2 shop_product表
product_id int 商品编号 自动编号
shop_id nvarchar 商店编号
product_name nvarchar 商品名称
product_bb nvarchar 商品介绍
product_price int 市场价
product_discount int 优惠价
product_img img 图片
product_status nvarchar 状态
product_first int 定金比例
product_type nvanchar 商品类型
存放商品资料

使用bka.java制成的javabean：bka.class可以提供对数据库的操作。

另外，需在控制面板的系统DSN中注册bka.dsn，
从而可使JSP通过JDBC-ODBC来调用sql数据库。
在页面中调用javabean，基本上可采用以下方式：

＜%@ page language="java" import="java.sql.*" %＞ ＜jsp:useBean id="RegisterBean" scope="page" class="shop.bka" /＞ ＜% String sql="select * from xxx"; ResultSet rs = RegisterBean.executeQuery(sql); if(rs.next()) { rs.close(); RegisterBean.closeStmt(); session.putValue("register_message","duplicate name found!"); } %＞ 注意应在使用后将rs关闭。 以下是bka.java的源程序。注意在使用前需用javac加以编译成为class文件即javabean. --shop/bka.java-- package shop; import java.sql.*; public class bka { String sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver"; String sConnStr = "jdbc:odbc:bka"; Connection conn = null; ResultSet rs = null; public bka() { try { Class.forName(sDBDriver); } catch(java.lang.ClassNotFoundException e) { System.err.println("bka(): " + e.getMessage()); } } public ResultSet executeQuery(String sql) { rs = null; try { conn = DriverManager.getConnection(sConnStr,"xxx","yyy"); Statement stmt = conn.createStatement(); rs = stmt.executeQuery(sql); } catch(SQLException ex) { System.err.println("aq.executeQuery: " + ex.getMessage()); } return rs; } }