? ? ? ?在學習JSP之后，很多人都會找個小模塊來練手，比如完成購物程序就是一個很好的模塊，那么我們應該如何用JSP完成購物程序呢？

下面是我用JSP和數據庫做的購物車的源程序：

注意：
1、重新計費部分還沒有做好，大家自己動手吧！
2、下一版本將用session做。

//shop_cart.jsp

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page session="true" %>
<%@ page language="java" import="java.sql.*" %>

<%

String product_type;
String action;
int product_id;
int curpage;

//商品類型
if (request.getParameter("product_type")==null){
product_type="all";
}else{
product_type=request.getParameter("product_type");
}

//頁數和商品類型參數，可以在“繼續購物”時返回到上次購物的頁面
if (request.getParameter("curpage")==null){
curpage=1;
}else{
curpage=java.lang.Integer.parseInt(request.getParameter("curpage"));
}

//動作
if (request.getParameter("action")==null){
action="view";
}else{
action=request.getParameter("action");
}

//商品編號
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);

//商店編號
session.putValue("shop_id",num);
//顧客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);
}
%>
?

?

align="center">

購物車為空!