这两天，在学习JSP，正好找个小模块来练练手：
下面就是实现购物车模块的页面效果截图：
图1. 产品显示页面 通过此页面进行产品选择，增加到购物车
图2 .购物车页面
图3 . 商品数量设置
好了，先不贴图了，直接上代码；先看看项目的文档结构把（麻雀虽小，五脏俱全）：
整个项目包括三个类，两个JSP页面，以下分别把他们的代码贴上：
Cart.java
package shopping.cart;import java.util.ArrayList;import java.util.Iterator;import java.util.List;public class Cart { List items = new ArrayList (); public List getItems() { return items; } public void setItems(List items) { this.items = items; } public void add(CartItem ci) { for (Iterator iter = items.iterator(); iter.hasNext();) { CartItem item = iter.next(); if(item.getProduct().getId() == ci.getProduct().getId()) { item.setCount(item.getCount() + 1); return; } } items.add(ci); } public double getTotalPrice() { double d = 0.0; for(Iterator it = items.iterator(); it.hasNext(); ) { CartItem current = it.next(); d += current.getProduct().getPrice() * current.getCount(); } return d; } public void deleteItemById(String productId) { for (Iterator iter = items.iterator(); iter.hasNext();) { CartItem item = iter.next(); if(item.getProduct().getId().equals(productId)) { iter.remove(); return; } } } } CartItem.java
package shopping.cart;import shopping.cart.Product;public class CartItem { private Product product; private int count; public int getCount() { return count; } public void setCount(int count) { this.count = count; } public Product getProduct() { return product; } public void setProduct(Product product) { this.product = product; }} Product.java
package shopping.cart;import java.io.Serializable;public class Product implements Serializable { private String id;// 产品标识 private String name;// 产品名称 private String description;// 产品描写叙述 private double price;// 产品价格 public Product() { } public Product(String id, String name, String description, double price) { this.id = id; this.name = name; this.description = description; this.price = price; } public void setId(String id) { this.id = id; } public void setName(String name) { this.name = name; } public void setDescription(String description) { this.description = description; } public void setPrice(double price) { this.price = price; } public String getId() { return id; } public String getName() { return name; } public String getDescription() { return description; } public double getPrice() { return price; }} 以下是俩JSP页面源代码：
ShowProducts.jsp
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%><%@ page import="shopping.cart.*"%><% String path = request.getContextPath(); String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";%>My JSP 'ShowProductsJSP.jsp' starting page <% Map products = new HashMap(); products.put("1", new Product("1", "mp3播放器", "效果非常不错的mp3播放器，存储空间达1GB", 100.00)); products.put("2", new Product("2", "数码相机", "象素500万，10倍光学变焦", 500.00)); products.put("3", new Product("3", "数码摄像机", "120万象素，支持夜景拍摄，20倍光学变焦", 200.00)); products.put("4", new Product("4", "迷你mp4", "市面所能见到的最好的mp4播放器，国产", 300.00)); products.put("5", new Product("5", "多功能手机", "集mp3播放、100万象素数码相机，手机功能于一体", 400.00)); products.put("6", new Product("6", "多功能手机111", "集mp3播放23、100万象素数码相机111，手机功能于一体111",600.00)); products.put("7", new Product("7", "11111111111", "集mp3播放23、100万象素数码相机111，手机功能于一体111",700.00)); products.put("8", new Product("8", "2222222222", "集mp3播放23、100万象素数码相机111，手机功能于一体111",800.00)); products.put("9", new Product("9", "33333333333333", "集mp3播放23、100万象素数码相机111，手机功能于一体111",900.00)); session.setAttribute("products", products); %>产品显示
Buy.jsp
<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%><%@ page import="shopping.cart.*" %><%Cart c = (Cart)session.getAttribute("cart");if(c == null) { c = new Cart(); session.setAttribute("cart", c);}double totalPrice = c.getTotalPrice();request.setCharacterEncoding("GBK");String action = request.getParameter("action");Map products = (HashMap)session.getAttribute("products");if(action != null && action.trim().equals("add")) { String id = request.getParameter("id"); Product p = (Product)products.get(id); CartItem ci = new CartItem(); ci.setProduct(p); ci.setCount(1); c.add(ci);}if(action != null && action.trim().equals("delete")) { String id = request.getParameter("id"); c.deleteItemById(id);}if(action != null && action.trim().equals("update")) { for(int i=0; i <%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%List items = c.getItems();%> 购物车 配置好相关文件，在tomcat中公布后，在浏览器中输入 就可以进入产品展示页面，其他操作都能够在页面上完毕！
注意：我使用的tomcatport（8088）被自己改过，假设没改过tomcatport的童鞋，默认port为8080。