使用Session和cookie会话对象实现简单购物车功能（超详细）

野性酷女 2024-04-01 16:49 77阅读 0赞

### 一、新建项目、实体类、servlet ###

1.新建Dynamic Web project，新建过程如下；  
![在这里插入图片描述][6e3194dd729144bfb3ccd2f9b7e811f7.png]  
2.在src目录下新建两个包，一个命名为entity，一个命名为servlet，新建过程如下；  
![在这里插入图片描述][87d3616a844d4ea4ad772b2b39398ccb.png]  
3.在entity目录下新建两个实体类，一个名为Cake,一个名为CakeDB,新建过程如下：![在这里插入图片描述][dddfc163d0664685931fe3c0c3a4058c.png]  
4.在servlet目录下新建三个servlet，命名分别为ListCakeServlet、PurchaseServlet和CartServlet，新建过程如下：  
![在这里插入图片描述][51c9bf6f170342519cc00cd023c7a838.png]  
所有东西建完后结果如图：  
![在这里插入图片描述][b7e13fa4e9ca48babd41f3f9daf6300c.png]

### 二：源代码 ###

1.Cake实体类：

package entity;
    
    public class Cake {
        
    	private String id;
    	private String name;
    	
    	public Cake() {
        
    	}
    	public Cake(String id, String name) {
        
    		this.id = id;
    		this.name = name;
    	}
    	
    	public void setId(String id) {
        
    		this.id=id;
    	}
    	public String getId() {
        
    		return id;
    	}
    	
    	public void setName(String name) {
        
    		this.name=name;
    	}
    	public String getName() {
        
    		return name;
    	}
    }

2.CakeDB实体类：

package entity;
 
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
 public class CakeDB {
 
 	private static Map<String, Cake> cake = new LinkedHashMap<String, Cake>();
 static {
 //模拟数据库中的记录
 cake.put("1001", new Cake("1001", "A类：巧克力蛋糕"));
 cake.put("1002", new Cake("1002", "B类：水果沙拉蛋糕"));
 cake.put("1003", new Cake("1003", "C类：慕斯蛋糕"));
 cake.put("1004", new Cake("1004", "D类：奶油蛋糕"));
 cake.put("1005", new Cake("1005", "E类：干果蛋糕"));
 }
 // 获得所有的蛋糕
 public static Collection<Cake> getAll() {
 
 return cake.values();
 }
 // 根据指定的id获蛋糕
 public static Cake getCake(String id) {
 
 return cake.get(id);
 }
 }

3.ListCakeServlet：

package servlet;
 
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.Collection;
 
 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 entity.Cake;
 import entity.CakeDB;
 
 @WebServlet("/ListCakeServlet")
 public class ListCakeServlet extends HttpServlet {
 
 	private static final long serialVersionUID = 1L;
 
 public ListCakeServlet() {
 
 super();
 }
 
 	protected void doGet(HttpServletRequest request, HttpServletResponse resp) 
 			throws ServletException, IOException {
 
 		resp.setContentType("text/html;charset=utf-8");
 PrintWriter out = resp.getWriter();
 Collection<Cake> cakes = CakeDB.getAll();
 out.write("本站提供的蛋糕有： ");
 for (Cake cake : cakes) {
 
 String url = "PurchaseServlet?id=" + cake.getId();
 out.write(cake.getName() + "<a href='" + url
 + "'>点击购买</a> ");
 }
 	}
 
 	protected void doPost(HttpServletRequest request, HttpServletResponse response)
 			throws ServletException, IOException {
 
 		doGet(request, response);
 	}
 }

4.PurchaseServlet：

package servlet;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 
 import entity.Cake;
 import entity.CakeDB;
 
 @WebServlet("/PurchaseServlet")
 public class PurchaseServlet extends HttpServlet {
 
 	private static final long serialVersionUID = 1L;
 
 public PurchaseServlet() {
 
 super();
 }
 
 	protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
 			throws ServletException, IOException {
 
 		// 获得用户购买的商品
 String id = req.getParameter("id");
 if (id == null) {
 
 // 如果id为null，重定向到ListBookServlet页面
 String url = "ListBookServlet";
 resp.sendRedirect(url);
 return;
 }
 Cake book = CakeDB.getCake(id);
 // 创建或者获得用户的Session对象
 HttpSession session = req.getSession();
 // 从Session对象中获得用户的购物车
 List<Cake> cart = (List) session.getAttribute("cart");
 if (cart == null) {
 
 // 首次购买，为用户创建一个购物车(List集合模拟购物车)
 cart = new ArrayList<Cake>();
 // 将购物城存入Session对象
 session.setAttribute("cart", cart);
 }
 // 将商品放入购物车
 cart.add(book);
 // 创建Cookie存放Session的标识号
 Cookie cookie = new Cookie("JSESSIONID", session.getId());
 cookie.setMaxAge(60 * 30);
 cookie.setPath("/Servlet");
 resp.addCookie(cookie);
 // 重定向到购物车页面
 String url = "CartServlet";
 resp.sendRedirect(url);
 	}
 
 	protected void doPost(HttpServletRequest request, HttpServletResponse response) 
 			throws ServletException, IOException {
 
 		doGet(request, response);
 	}
 
 }

5.CartServlet:

package servlet;
 
 
 import entity.Cake;
 
 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;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.List;
 
 @WebServlet("/CartServlet")
 
 public class CartServlet extends HttpServlet {
 
 
 
 
 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException{
 
 resp.setContentType("text/html;charset=utf-8");
 PrintWriter out = resp.getWriter();
 List<Cake> cart = null;
 boolean purFlag = true;
 HttpSession session = req.getSession(false);
 if (session == null)
 {
 
 purFlag =false;
 }
 else {
 
 cart = (List) session.getAttribute("cart");
 
 if (cart == null){
 
 purFlag=false;
 }
 }
 
 if(!purFlag){
 
 out.write("抱歉，您还没有购买任何商品！ ");
 }
 else {
 
 out.write("您购买的蛋糕有： ");
 double price = 0;
 for (Cake cake:cart){
 
 out.write(cake.getName() +" ");
 }
 }
 
 }
 
 
 }

### 三、运行 ###

1.在ListCakeServlet文件下运行，点击鼠标右键，选择run as，具体如图:  
![在这里插入图片描述][b87645f128ad4ebdbf6063839005464a.png]  
2.运行结果如图：  
![在这里插入图片描述][e747069348dc4f39988118edf27fbdf2.png]  
点击购买之后跳转CartServlet页面，比如我点了巧克力蛋糕后：

![在这里插入图片描述][9c0cad7028474f99897e39a394daaddd.png]  
以上就是使用Session和cookie会话对象实现简单购物车功能。希望对你有帮助哦~

[6e3194dd729144bfb3ccd2f9b7e811f7.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/9f31789ab478409d95a18d5e995c3114.png
[87d3616a844d4ea4ad772b2b39398ccb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/c345d5c8ffc34c5ea56e5e7e5cbe8c13.png
[dddfc163d0664685931fe3c0c3a4058c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/cf2a4a0424614da3a9daec5b6d2aede6.png
[51c9bf6f170342519cc00cd023c7a838.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/f0deb10b11ad418381481dd0d70381bd.png
[b7e13fa4e9ca48babd41f3f9daf6300c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/24fbab97788f47c293bb26b21814a367.png
[b87645f128ad4ebdbf6063839005464a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/f45021e3873141339c79a178d6f8ab61.png
[e747069348dc4f39988118edf27fbdf2.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/14e259119f5f4bdfb7425cea953231e6.png
[9c0cad7028474f99897e39a394daaddd.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/16d732db0e1b4da88da8ba91f3104c39.png