用java代码写一个简单的网上购物车程序

 需求：1、写一个商品类，有商品编号、商品名称、商品分类、商品单价属性。2、写一个商品条目信息类，有商品和数量两个属性，有商品总价格方法。

 3、写一个购物车类，有添加商品方法、查看订单信息，删除商品，修改商品，清空购物车，求购物车中所有商品总金额方法。4、写一个测试类，测试上述方法。

 商品类：
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     public class Product {
         private int productId;// 商品编号
         private String productName;// 商品名称
         private String category;// 商品分类
         private double price;// 单价  

         public Product() {// 无参构造
             super();
         }  

         public Product(int productId, String productName, String category,
                 double price) {
             super();
             this.productId = productId;
             this.productName = productName;
             this.category = category;
             this.price = price;
         }  

         public String toString() {
             return "Product [productId=" + productId + ", productName="
                     + productName + ", category=" + category + ", price=" + price
                     + "]";
         }  

         public int getProductId() {
             return productId;
         }  

         public void setProductId(int productId) {
             this.productId = productId;
         }  

         public String getProductName() {
             return productName;
         }  

         public void setProductName(String productName) {
             this.productName = productName;
         }  

         public String getCategory() {
             return category;
         }  

         public void setCategory(String category) {
             this.category = category;
         }  

         public double getPrice() {
             return price;
         }  

         public void setPrice(double price) {
             this.price = price;
         }  

     }  

 商品条目信息类：
 [java] view plain copy

     public class ProductItem {
         private Product product;//购买的商品
         private int count;//商品数量
         public double totalMoney(){//小计
             double price=product.getPrice();//获取商品单价
             return price*count;
         }  

         public ProductItem() {
             super();
         }  

         public ProductItem(Product product, int count) {
             super();
             this.product = product;
             this.count = count;
         }  

         public Product getProduct() {
             return product;
         }
         public void setProduct(Product product) {
             this.product = product;
         }
         public int getCount() {
             return count;
         }
         public void setCount(int count) {
             this.count = count;
         }  

     }  

 购物车类：
 [java] view plain copy

     import java.util.Collection;
     import java.util.Iterator;
     import java.util.LinkedHashMap;
     import java.util.Map;
     public class ShoppingCart {//购物车
         //key：商品编号 value:商品条目
         private Map<Integer,ProductItem> map=new LinkedHashMap<Integer,ProductItem>();  

         public void addProduct(Product p){//添加商品
             int productId=p.getProductId();
             if(map.containsKey(productId)){
                 ProductItem productItem=map.get(productId);
                 productItem.setCount(productItem.getCount()+1);
             }else{
                 map.put(productId, new ProductItem(p,1));
             }
         }
         public void showAll(){//查看订单信息
             Collection<ProductItem> productItems = map.values();
             Iterator<ProductItem> iterator = productItems.iterator();
             while(iterator.hasNext()){
                 ProductItem productItem = iterator.next();
                 Product product = productItem.getProduct();
                 System.out.println("商品编号："+product.getProductId()+",商品名称："
                 +product.getProductName()+",单价："+product.getPrice()+",数量："+productItem.getCount()
                 +",小计："+productItem.totalMoney());
             }
         }
         public boolean deleteProduct(int productId){//删除商品
             if(map.containsKey(productId)){
                 map.remove(productId);
                 return true;
             }
             return false;
         }
         public boolean modifyProduct(int productId,int count){//修改
             if(map.containsKey(productId)){
                 if(count>=1){
                     ProductItem productItem = map.get(productId);
                     productItem.setCount(count);
                     return true;
                 }else if(count==0){//删除该商品
                     deleteProduct(productId);
                     return true;
                 }
             }
             return false;
         }  

         public void clearCart(){//清空购物车
             map.clear();
         }  

         public double totalAllMoney(){//商品总钱数
             double total=0;
             Collection<ProductItem> productItems = map.values();
             Iterator<ProductItem> iterator = productItems.iterator();
             while(iterator.hasNext()){
                 ProductItem productItem = iterator.next();
                 double money=productItem.totalMoney();
                 total+=money;
             }
             return total;
         }
     }  

 测试类：
 [java] view plain copy

         public class ShoppingCartTest {  

             public static void main(String[] args) {
                 ShoppingCart cart=new ShoppingCart();
                 Product p1=new Product(101,"华硕笔记本","笔记本",4599);
                 Product p2=new Product(102,"苹果","水果",5.9);
                 Product p3=new Product(103,"彩电","家电",2799);
                 Product p4=new Product(104,"秋裤","服装",128);
                 Product p5=new Product(105,"华为手机","手机",2998);
                 Product p6=new Product(101,"华硕笔记本","笔记本",4599);//测试买两件商品的情况
                 cart.addProduct(p1);
                 cart.addProduct(p2);
                 cart.addProduct(p3);
                 cart.addProduct(p4);
                 cart.addProduct(p5);
                 cart.addProduct(p6);
                 cart.showAll();
                 System.out.println("############");
                 boolean flag=cart.deleteProduct(p2.getProductId());
                 if(flag){
                     System.out.println("商品编号为："+p2.getProductId()+"的商品删除成功！");
                 }else{
                     System.out.println("删除失败");
                 }
                 cart.showAll();
                 System.out.println("############");
                 boolean flag2=cart.modifyProduct(p3.getProductId(), 2);
                 if(flag2){
                     System.out.println("商品编号为："+p3.getProductId()+"的商品修改成功！");
                 }else{
                     System.out.println("修改失败");
                 }
                 cart.showAll();  

                 //cart.clearCart();
                 //cart.showAll();
                 System.out.println("商品总价钱为："+cart.totalAllMoney());  

             }  

         }