servlet之session设置
商品对象,购物车对象,servlet的实现
商品:
package app02d;
public class Product {
private int id;
private String name;
private String description;
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;
}
}
购物车:
package app02d;
public class ShoppingItem {
private Product product;
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;
}
}
servlet的实现:
package app02d;
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;
/**
* Servlet implementation class ShoppingCartServlet
*/
@WebServlet( name = "ShoppingCartServlet", urlPatterns = {"/products", "/viewProductDetails","/addToCart","/viewCart"})
public class ShoppingCartServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String CART_ATTRIBUTE = "cart";
private List<Product> products = new ArrayList<Product>();
private NumberFormat currencyFormat = NumberFormat
.getCurrencyInstance(Locale.US);
// 创建商品对象,加入商品列表中(1)
@Override
public void init() throws ServletException {
products.add(new Product(1, "Bravo 32' HDTV",
"Low-cost HDTV from renowned TV manufacturer",
159.95F));
products.add(new Product(2, "Bravo BluRay Player",
"High quality stylish BluRay player", 99.95F));
products.add(new Product(3, "Bravo Stereo System",
"5 speaker hifi system with iPod player",
129.95F));
products.add(new Product(4, "Bravo iPod player",
"An iPod plug-in that can play multiple formats",
39.95F));
}
/**
* @see HttpServlet#HttpServlet()
*/
public ShoppingCartServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* 分支(2)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String uri = request.getRequestURI();
if (uri.endsWith("/products")) {
// 查询商品列表
sendProductList(response);
} else if (uri.endsWith("/viewProductDetails")) {
// 显示商品详细信息
sendProductDetails(request, response);
} else if (uri.endsWith("viewCart")) {
// 显示购物车
showCart(request, response);
}
}
/**
* addToCart
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// add to cart
int productId = 0; // 商品id
int quantity = 1; // 商品数量(默认购买一件)
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);
// 创建session对象
HttpSession session = request.getSession();
List<ShoppingItem> cart = (List<ShoppingItem>) session.getAttribute(CART_ATTRIBUTE);
if (cart == null) {
cart = new ArrayList<ShoppingItem>();
// 设置session值
session.setAttribute(CART_ATTRIBUTE, cart);
}
cart.add(shoppingItem);
}
sendProductList(response);
}
/**
* 显示商品列表 (4)
* @param response
* @throws IOException
*/
private void sendProductList(HttpServletResponse response)
throws IOException {
response.setContentType("text/html");
PrintWriter writer = response.getWriter();
writer.println("<html><head><title>Products</title>" +
"</head><body><h2>Products</h2>");
writer.println("<ul>");
for (Product product : products) {
writer.println("<li>" + product.getName() + "("
+ currencyFormat.format(product.getPrice())
// 商品详细信息的显示
+ ") (" + "<a href='viewProductDetails?id="
+ product.getId() + "'>Details</a>)");
}
writer.println("</ul>");
writer.println("<a href='viewCart'>View Cart</a>");
writer.println("</body></html>");
}
/**
* 根据商品id获取商品对象
* @param productId
* @return
*/
private Product getProduct(int productId) {
for (Product product : products) {
if (product.getId() == productId) {
return product;
}
}
return null;
}
/**
* 获取商品的详细信息,并显示
* @param request
* @param response
* @throws IOException
*/
private void sendProductDetails(HttpServletRequest request,
HttpServletResponse response) throws IOException {
response.setContentType("text/html");
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>Product Details</title></head>"
+ "<body><h2>Product Details</h2>"
+ "<form method='post' action='addToCart'>");
// 隐藏域
writer.println("<input type='hidden' name='id' "
+ "value='" + productId + "'/>");
writer.println("<table>");
writer.println("<tr><td>Name:</td><td>"
+ product.getName() + "</td></tr>");
writer.println("<tr><td>Description:</td><td>"
+ product.getDescription() + "</td></tr>");
writer.println("<tr>" + "<tr>"
// 购买的数量
+ "<td><input name='quantity'/></td>"
+ "<td><input type='submit' value='Buy'/>"
+ "</td>"
+ "</tr>");
writer.println("<tr><td colspan='2'>"
+ "<a href='products'>Product List</a>"
+ "</td></tr>");
writer.println("</table>");
writer.println("</form></body>");
} else {
writer.println("No product found");
}
}
/**
* 显示购物车
* @param request
* @param response
* @throws IOException
*/
private void showCart(HttpServletRequest request,
HttpServletResponse response) throws IOException {
response.setContentType("text/html");
PrintWriter writer = response.getWriter();
writer.println("<html><head><title>Shopping Cart</title>"
+ "</head>");
writer.println("<body><a href='products'>" +
"Product List</a>");
// 创建session对象
HttpSession session = request.getSession();
// 获取session内容
List<ShoppingItem> cart = (List<ShoppingItem>) session.getAttribute(CART_ATTRIBUTE);
if (cart != null) {
writer.println("<table>");
writer.println("<tr><td style='width:150px'>Quantity"
+ "</td>"
+ "<td style='width:150px'>Product</td>"
+ "<td style='width:150px'>Price</td>"
+ "<td>Amount</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'>"
+ "Total:"
+ currencyFormat.format(total)
+ "</td></tr>");
writer.println("</table>");
}
writer.println("</table></body></html>");
}
}
