product类：
package com.lab;
public class Product {
private int id; // 商品编号
private String name; // 商品名称
private String description; // 商品描述
private float price; // 商品价格
// 构造方法
public Product(int id, String name, String description, float price) {
this.id = id;
this.name = name;
this.description = description;
this.price = price;
}
// 各属性的setter方法和getter方法
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
}
showshoppingitem类：
package com.lab;
import java.io.Serializable;
public class ShoppingItem implements Serializable {
private Product product; // 商品信息
private int quantity; // 商品数量
public ShoppingItem(Product product, int quantity) {
this.product = product;
this.quantity = quantity;
}
// 属性的getter方法和setter方法
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
public int getQuantity() {
return quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
}
ShoppingCartServlet
package com.lab;
import com.lab.Product;
import com.lab.ShoppingItem;
import java.io.*;
import java.util.ArrayList;
//import java.awt.List;
import java.util.List;
import java.awt.Component;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.Serializable;
import javax.servlet.annotation.WebServlet;
@WebServlet(name = "ShoppingCartServlet", urlPatterns = {
"/products", "/viewProductDetails",
"/addToCart", "/viewCart", "/deleteItem" })
public class ShoppingCartServlet extends HttpServlet {
// products是存放所有商品的List对象
private List <Product> products = new ArrayList <Product>();
@Override
public void init() throws ServletException {
products.add(new Product(1, "单反相机",
"尼康性价比最高的单反相机",4159.95F));
products.add(new Product(2, "三星手机",
"三星公司的最新iPhone5产品", 1199.95F));
products.add(new Product(3, "笔记本电脑",
"联想公司的新一代产品",5129.95F));
products.add(new Product(4, "平板电脑",
"苹果公司的新产品",1239.95F));
}
@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException {
String uri = request.getRequestURI();
// 根据请求URI决定调用哪个方法
if (uri.endsWith("/products")) {
showProductList(response);
} else if (uri.endsWith("/viewProductDetails")) {
showProductDetails(request, response);
} else if (uri.endsWith("viewCart")) {
showCart(request, response);
} else if (uri.endsWith("deleteItem")) {
deleteItem(request, response);
}
}
// 该方法用于显示所有商品信息
private void showProductList(HttpServletResponse response)
throws IOException {
response.setContentType("text/html;charset=gb2312");
PrintWriter out = response.getWriter();
out.println("<html><head><title>商品列表</title>" +
"</head><body><p>商品列表</p>");
out.println("<ul>");
for (Product product : products) {
out.println("<li>" + product.getName() + "("
+ product.getPrice()
+ ") (" + "<a href='viewProductDetails?id="
+ product.getId() + "'>详细信息</a>)");
}
out.println("</ul>");
out.println("<a href='viewCart'>查看购物车</a>");
out.println("</body></html>");
}
private void showProductDetails(HttpServletRequest request,
HttpServletResponse response) throws IOException {
response.setContentType("text/html;charset=gb2312");
PrintWriter out = response.getWriter();
int productId = 0;
try {
productId = Integer.parseInt(
request.getParameter("id"));
} catch (NumberFormatException e){
}
// 根据商品号返回商品对象
Product product = getProduct(productId);
if (product != null) {
out.println("<html><head>"
+ "<title>商品详细信息</title></head>"
+ "<body><p>商品详细信息</p>"
+ "<form method='post' action='addToCart'>");
// 这里使用隐藏表单域存储商品号信息
out.println("<input type='hidden' name='id' "
+ "value='" + productId + "'/>");
out.println("<table>");
out.println("<tr><td>商品名:</td><td>"
+ product.getName() + "</td></tr>");
out.println("<tr><td>说明:</td><td>"
+ product.getDescription() + "</td></tr>");
out.println("<tr><td>价格:</td><td>"
+ product.getPrice() + "</td></tr>");
out.println("<tr>" + "<tr>"
+ "<td><input name='quantity'/></td>"
+ "<td><input type='submit' value='购买'/>"
+ "</td>"
+ "</tr>");
out.println("<tr><td colspan='2'>"
+ "<a href='products'>商品列表</a>"
+ "</td></tr>");
out.println("</table>");
out.println("</form></body>");
} else {
out.println("No product found");
}
}
// 根据商品号返回商品对象方法
private Product getProduct(int productId) {
for (Product product : products) {
if (product.getId() == productId) {
return product;
}
}
return null;
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
// 将购买的商品添加到购物车中
int productId = 0;
int quantity = 0;
try {
productId = Integer.parseInt(
request.getParameter("id"));
quantity = Integer.parseInt(request
.getParameter("quantity"));
} catch (NumberFormatException e) { }
Product product = getProduct(productId);
if (product != null && quantity >= 0) {
// 创建一个商品条目
ShoppingItem shoppingItem = new ShoppingItem(
product, quantity);
HttpSession session = request.getSession();
// 在会话对象中查找购物车对象
List<ShoppingItem> cart = (List<ShoppingItem>) session
.getAttribute("cart");
if (cart == null) {
// 如果在会话对象上找不到购物车对象，则创建一个
cart = new ArrayList<ShoppingItem>();
// 将购物车对象存储到会话对象上
session.setAttribute("cart", cart);
}
// 将商品添加到购物车对象中
cart.add(shoppingItem);
}
showProductList(response);
}
public void deleteItem(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
int productId = 0,i=0;
try {
productId = Integer.parseInt(
request.getParameter("id"));
} catch (NumberFormatException e) { }
HttpSession session = request.getSession();
List<ShoppingItem> cart = (List<ShoppingItem>) session.getAttribute("cart");
for (i=0;i<cart.size();i++){
ShoppingItem p=cart.get(i);
if (p.getProduct().getId()==productId)
{
cart.remove(i);
break;
}
}
response.sendRedirect("http://localhost:8080/helloapp/viewCart");
}
private void showCart(HttpServletRequest request,
HttpServletResponse response) throws IOException {
response.setContentType("text/html;charset=gb2312");
PrintWriter out = response.getWriter();
out.println("<html><head><title>购物车</title></head>");
out.println("<body><a href='products'>" +
"商品列表</a>");
HttpSession session = request.getSession();
List<ShoppingItem> cart = (List<ShoppingItem>) session
.getAttribute("cart");
if (cart != null) {
out.println("<table>");
out.println("<tr><td style='50px'>数量"
+ "</td>"
+ "<td style='80px'>商品</td>"
+ "<td style='80px'>价格</td>"
+ "<td style='80px'>小计</td>"
+ "<td style='80px'>是否删除</td></tr>");
double total = 0.0;
for (ShoppingItem shoppingItem : cart) {
Product product = shoppingItem.getProduct();
int quantity = shoppingItem.getQuantity();
if (quantity != 0) {
float price = product.getPrice();
out.println("<tr>");
out.println("<td>" + quantity + "</td>");
out.println("<td>" + product.getName()
+ "</td>");
out.println("<td>" + price + "</td>");
// 计算小计并实现四舍五入
double subtotal = ((int)(price * quantity*100+0.5))/100.00;
out.println("<td>" + subtotal + "</td>");
out.println("<td><a href=deleteItem?id=" +
product.getId()+">"+"删除</a>" + "</td>");
total += subtotal;
out.println("</tr>");
}
}
out.println("<tr><td colspan='4' "
+ "style='text-align:right'>"
+ "总计:" + total + "</td></tr>");
out.println("</table>");
}
out.println("</table></body></html>");
}
}