jsp实现购物程序

下面是我用JSP和数据库做的购物车的源程序：

注意：
1、重新计费部分还没有做好，大家自己动手吧！
2、下一版本将用session做。

//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&quo