示例代码:
package com.cdc.test;public class Product {/** 产品id **/private int id;/** 产品名字 **/private String name;/*** 产品描述 **/private String description;/** 产品价钱 **/private float price;public Product(int id, String name, String description, float price) {this.id = id;this.name = name;this.description = description;this.price = price;}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;}
}
package com.cdc.test;public class ShoppingItem {private Product product;/***产品数量**/private int quantity;public ShoppingItem(Product product, int quantity) {this.product = product;this.quantity = quantity;}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;}
}
package com.cdc.test;import java.io.IOException;
import java.io.PrintWriter;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;@WebServlet(name = "ShoppingCartServlet", urlPatterns = { "/products","/viewProductDetails", "/addToCart", "/viewCart" })
public class ShoppingCartServlet extends HttpServlet {private static final long serialVersionUID = -20L;private static final String CART_ATTRIBUTE = "cart";private List<Product> products = new ArrayList<Product>();private NumberFormat currencyFormat = NumberFormat.getCurrencyInstance(Locale.CHINA);@Overridepublic void init() throws ServletException {products.add(new Product(1, "电视机", "高清电视机", 159.95F));products.add(new Product(2, "电脑-台式机", "联想台式机", 99.95F));products.add(new Product(3, "笔记本电脑--联想", "联想笔记本", 129.95F));products.add(new Product(4, "华为--硬盘", "华为高端存储", 39.95F));}/*** Servlet默认会调用get方法 **/@Overridepublic void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String uri = request.getRequestURI();if (uri.endsWith("/products")) {sendProductList(response);} else if (uri.endsWith("/viewProductDetails")) {sendProductDetails(request, response);} else if (uri.endsWith("viewCart")) {showCart(request, response);}}@Overridepublic void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// add to cart/** 产品的id **/int productId = 0;/** 产品的数量 **/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) {ShoppingItem shoppingItem = new ShoppingItem(product, quantity);/***获取session,并且查看里面是否有包含有一个CART_ATTRIBUTE的属性,如果有就把它添加到ShoppingItem里面,如果没有就创建一个.***/HttpSession session = request.getSession();@SuppressWarnings("unchecked")List<ShoppingItem> cart = (List<ShoppingItem>) session.getAttribute(CART_ATTRIBUTE);if (cart == null) {cart = new ArrayList<ShoppingItem>();/***将包含有产品数量和产品信息的集合添加到session---CART_ATTRIBUTE里面**/session.setAttribute(CART_ATTRIBUTE, cart);}cart.add(shoppingItem);}sendProductList(response);}private void sendProductList(HttpServletResponse response)throws IOException {response.setContentType("text/html;charset=utf-8");PrintWriter writer = response.getWriter();writer.println("<html><head><title>产品</title>"+ "</head><body><h2>产品</h2>");writer.println("<ul>");for (Product product : products) {writer.println("<li>" + product.getName() + "("+ currencyFormat.format(product.getPrice()) + ") ("+ "<a href='viewProductDetails?id=" + product.getId()+ "'>详情</a>)");}writer.println("</ul>");writer.println("<a href='viewCart'>查看购物车</a>");writer.println("</body></html>");}private Product getProduct(int productId) {for (Product product : products) {if (product.getId() == productId) {return product;}}return null;}private void sendProductDetails(HttpServletRequest request,HttpServletResponse response) throws IOException {response.setContentType("text/html;charset=utf-8");PrintWriter writer = response.getWriter();int productId = 0;try {productId = Integer.parseInt(request.getParameter("id"));} catch (NumberFormatException e) {}Product product = getProduct(productId);if (product != null) {writer.println("<html><head>"+ "<title>产品详情</title></head>"+ "<body><h2>产品详情</h2>"+ "<form method='post' action='addToCart'>");writer.println("<input type='hidden' name='id' " + "value='"+ productId + "'/>");writer.println("<table>");writer.println("<tr><td>名称:</td><td>" + product.getName()+ "</td></tr>");writer.println("<tr><td>描述:</td><td>"+ product.getDescription() + "</td></tr>");writer.println("<tr>" + "<tr>"+ "<td><input name='quantity'/></td>"+ "<td><input type='submit' value='购买'/>" + "</td>"+ "</tr>");writer.println("<tr><td colspan='2'>"+ "<a href='products'>产品列表</a>" + "</td></tr>");writer.println("</table>");writer.println("</form></body>");} else {writer.println("没有此产品");}}private void showCart(HttpServletRequest request,HttpServletResponse response) throws IOException {response.setContentType("text/html;charset=utf-8");PrintWriter writer = response.getWriter();writer.println("<html><head><title>购物车</title>" + "</head>");writer.println("<body><a href='products'>" + "产品列表</a>");/***获取在doPost()里面设置到session里面的值**/HttpSession session = request.getSession();@SuppressWarnings("unchecked")List<ShoppingItem> cart = (List<ShoppingItem>) session.getAttribute(CART_ATTRIBUTE);if (cart != null) {writer.println("<table>");writer.println("<tr><td style='width:150px'>数量" + "</td>"+ "<td style='width:150px'>产品</td>"+ "<td style='width:150px'>单价</td>"+ "<td>总额</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();writer.println("<tr>");writer.println("<td>" + quantity + "</td>");writer.println("<td>" + product.getName() + "</td>");writer.println("<td>" + currencyFormat.format(price)+ "</td>");double subtotal = price * quantity;writer.println("<td>" + currencyFormat.format(subtotal)+ "</td>");total += subtotal;writer.println("</tr>");}}writer.println("<tr><td colspan='4' " + "style='text-align:right'>"+ "合计:" + currencyFormat.format(total) + "</td></tr>");writer.println("</table>");}writer.println("</table></body></html>");}
}