一个购物车添加商品程序（java+ajax+servlet）

来源：互联网发布：如何有刘诗诗气质知乎编辑：程序博客网时间：2024/05/21 14:56

页面：

描述：一个简单的购物车程序，点击加入购物车链接后，相应的结果实时更新（商品名、总数量、总价格）

1、页面代码：

<html>

<head>

</head>

<body>

商品 <span id="bookName"></span> 已加入购物车，购物车中共有书本 <span id="totalBook"></span> 本，总价格为 <span id="totalMoney"></span> 元<br><br>

Java<a href="addToCart?id=java&price=100">加入购物车</a>

Oracle<a href="addToCart?id=oracle&price=120">加入购物车</a>

</body>

</html>

2、javaBean类（书本属性）：ShoppingCartItem，书本的三个属性：number，bookName，price

package com.code;

public class ShoppingCartItem {
private int number=0;
private String bookName=null;
private int price=0;
public int getNumber() {
  return number;
}
public void setNumber(int number) {
  this.number = number;
}
public String getBookName() {
  return bookName;
}
public void setBookName(String bookName) {
  this.bookName = bookName;
}
public int getPrice() {
  return price;
}
public void setPrice(int price) {
  this.price = price;
}
}

3、java类：ShoppingCart ，使用一个Map存放书本对象

import java.util.HashMap;
import java.util.Map;
import com.code.ShoppingCartItem;

public class ShoppingCart {
//存放书本信息的Map
private Map<String,ShoppingCartItem> items = new HashMap<String,ShoppingCartItem>();

    public void addToCart(String bookName,int price){      //加入购物车(参数由servlet传递而来)
     if(items.containsKey(bookName)){
      ShoppingCartItem item = items.get(bookName);
      item.setNumber(item.getNumber()+1);
    }else{
      ShoppingCartItem item = new ShoppingCartItem();
      item.setBookName(bookName);
      item.setNumber(1);
      item.setPrice(price);

      items.put(bookName, item);
    }
    }
    public int getTotalNumber(){                  //计算总数
     int total=0;
    for(ShoppingCartItem item:items.values()){
      total+=item.getNumber();
    }
    return total;
    }

    public int getTotalMonry(){                //计算总价格
     int money=0;
    for(ShoppingCartItem item:items.values()){
      money+=item.getNumber()*item.getPrice();
    }
    return money;
    }
}

4、Servlet类：

package com.code;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class AddToCartServlet extends HttpServlet {

/**
* Constructor of the object.
*/
public AddToCartServlet() {
super();
}

/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {


  //1，获取请求参数id，price；
  String bookName = request.getParameter("id");
  int price = Integer.parseInt(request.getParameter("price"));

  //2，获取购物车对象；
  HttpSession session = request.getSession();
  ShoppingCart sc = (ShoppingCart)session.getAttribute("sc");

  if(sc == null){
   sc = new ShoppingCart();
   session.setAttribute("sc", sc);
  }
  //3，把点击的选项加入到购物车中；
  sc.addToCart(bookName, price);

  //4准备响应JSON对象：{"bookName":.....}
  StringBuilder result = new StringBuilder();

//拼装JSON数据，不能使单引号'
  result.append("{").append("\"bookName\":\""+bookName+"\"").append(",").append("\"totalMoney\":"+sc.getTotalMonry()).append(",").append ("\"totalBook\":"+sc.getTotalNumber()).append("}");

  //5、响应JSON
  response.setContentType("text/javascript");  //声明类型
  response.getWriter().print(result.toString());

}

public void init() throws ServletException {
// Put your code here
}

}

5、页面脚本：

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