第4次任务:迭代改进购物车2（购物车需求变更：使用继承、接口与多态）
| 任务 | 姓名 |
|---|---|
| 编码规范、前期调查与功能设计、博客制作、UML类图 | 黄帅 |
| 面向对象设计、博客制作、功能设计 | 韩龙飞 |
1.前期调查与功能设计
我们以京东商城为例来进行探讨，首先，进入商城主界面时，我们可以看到许多商城中的物品，而上方的搜索栏可以帮助我们搜索想要的物品。
点击物品图标，我们可以看到物品的详细信息，还可以执行“加入购物车“这一操作。
进入购物车时，我们能够看到自己购买了什么东西、购买多少个，以及预估的结算价格，而且我们可以在购物车中执行删除操作，能够删除任意商品、任意数量。
从以上观察的情况来看，购物车程序所需要实现的功能大致有：
- 需要有商品的搜索功能（可能需要一个用户类来识别并执行用户操作）
- 需要有购物车中物品的添加功能和删除功能（需要一个购物车类来存放购买物品的数量和总价）
- 在购物车中需要有显示结算总价的程序（需要一个账单类来打印支付凭条）
- 由于个人设计的程序中的商品不会像网络商场一样多的数不过来，所以可以考虑做出一个可以显示商城中所有商品的商品清单功能。（需要一个商品类来存储商品的基本信息，还可能有全部商品信息输出的功能）
2.面向对象设计
在上述的故事中，用红色字代表可能的对象(名词)或属性，用蓝色字代表可能的方法（动词）。
这样，通过讲故事的方法，我们就可以思路清晰的找出一个程序所需要的类和其中的方法。
3.系统功能结构图
4.功能设计
5.UML图
6.关键代码
商品类父类
package shop;
import java.math.BigDecimal;
public class Commodity {
private int id;
private String name;
private BigDecimal price;
private String description;
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 BigDecimal getPrice() {
return price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
}
商品类子类
package shop;
import java.math.BigDecimal;
public class Food extends Commodity {
private String shelfLife;// 保质期
private String date = "见包装";
public Food() {
super();
// TODO Auto-generated constructor stub
}
public Food(Integer id, String name, BigDecimal price, String shelfLife) {
this.setId(id);
this.setName(name);
this.setPrice(price);
this.setDescription("Food");
this.shelfLife = shelfLife;
}
public String getShelfLife() {
return shelfLife;
}
public void setShelfLife(String shelfLife) {
this.shelfLife = shelfLife;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
@Override
public String toString() {
return "Food [id: " + this.getId() + ", name: " + this.getName() + ", price: " + this.getPrice()
+ ", shelfLife: " + shelfLife + ", date: " + date;
}
}
package shop;
import java.math.BigDecimal;
public class Clothes extends Commodity {
private String size;
private String brand;
public Clothes() {
super();
// TODO Auto-generated constructor stub
}
public Clothes(Integer id, String name, BigDecimal price, String size, String brand) {
this.setId(id);
this.setName(name);
this.setPrice(price);
this.setDescription("Clothes");
this.size = size;
this.brand = brand;
}
public String getSize() {
return size;
}
public void setSize(String size) {
this.size = size;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
@Override
public String toString() {
return "Clothes [id: " + this.getId() + ", name: " + this.getName() + ", price: " + this.getPrice() + ", size: "
+ size + ", brand: " + brand;
}
}
package shop;
import java.math.BigDecimal;
public class Book extends Commodity {
@Override
public String toString() {
return "Book [id: " + this.getId() + ", name: " + this.getName() + ", price: " + this.getPrice() + ", author: "
+ author + ", press: " + press;
}
private String author;
private String press;
public Book(Integer id, String name, BigDecimal price, String author, String press) {
this.setId(id);
this.setName(name);
this.setPrice(price);
this.setDescription("Book");
this.author = author;
this.press = press;
}
public Book() {
super();
// TODO Auto-generated constructor stub
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public String getPress() {
return press;
}
public void setPress(String press) {
this.press = press;
}
}
购物车条目类
package shop;
public class cartItem {
public cartItem(Commodity item, int amount) {
super();
this.item = item;
this.amount = amount;
}
Commodity item;
int amount;
public Commodity getItem() {
return item;
}
public void increase(int number) {
amount = amount + number;
}
public void decrease(int number) {
amount = amount - number;
if (amount < 0)
amount = 0;
}
public void setItem(Commodity item) {
this.item = item;
}
public int getAmount() {
return amount;
}
public int getId() {
return item.getId();
}
public void setAmount(int amount) {
this.amount = amount;
}
@Override
public String toString() {
return "cartItem [item=" + item + ", amount=" + amount + "]";
}
}
货架DAO
package shop;
public interface ShelfDao {
public void showCommodity();
public void addCommodity(Commodity e);
public void subCommodity(Commodity e);
public Commodity idSearch(int id);// 根据id找商品
// 根据关键词找商品
public boolean nameSearch(String name);
}
package shop;
import java.util.ArrayList;
public class ShelfDaoImpl implements ShelfDao {
private ArrayList<Commodity> shelfList;
/**
*
*/
public ShelfDaoImpl() {
shelfList = new ArrayList<>();
}
public void showCommodity() {
System.out.println("商品ID 商品名 商品价格");
for (Commodity x : shelfList) {
System.out.println(x.getId() + " " + x.getName() + " " + x.getPrice());
}
}
public void addCommodity(Commodity e) {
if (e == null) {
return;
}
for (int i = 0; i < shelfList.size(); i++) {
if (shelfList.get(i).getId() == e.getId()) {
System.out.println("该商品已存在");
return;
}
}
shelfList.add(e);
}
public void subCommodity(Commodity e) {
for (int i = 0; i < shelfList.size(); i++) {
if (shelfList.get(i).getId() == e.getId()) {
shelfList.remove(i);
break;
}
}
}
public Commodity idSearch(int id) {
for (int i = 0; i < shelfList.size(); i++) {
if (shelfList.get(i).getId() == id) {
return shelfList.get(i);
}
}
return null;
}
public boolean nameSearch(String name) {
int count = 0;
for (int i = 0; i < shelfList.size(); i++) {
if (shelfList.get(i).getName().indexOf(name) != -1) {
count++;
if (count == 1) {
System.out.println("查找结果如下 : ");
System.out.println();
System.out.println("商品ID 商品名 商品价格");
}
System.out.println(shelfList.get(i).getId() + " " + shelfList.get(i).getName() + " "
+ shelfList.get(i).getPrice());
}
}
if (count == 0)
return false;
else
return true;
}
}
购物车DAO
package shop;
public interface ShoppingCartDao {
public boolean cartAdd(Commodity e, int number);// 加入购物车
public boolean cartsub(int id, int number);
public void showCart();
public void cleanCart();
}
package shop;
import java.util.ArrayList;
public class ShoppingCartDaoImpl implements ShoppingCartDao {
private ArrayList<cartItem> itemList;
public ShoppingCartDaoImpl() {
itemList = new ArrayList<>();
}
public boolean cartAdd(Commodity e, int number) {
if (e == null)
return false;
for (int i = 0; i < itemList.size(); i++) {
if (itemList.get(i).getId() == e.getId()) {
itemList.get(i).increase(number);
}
}
itemList.add(new cartItem(e, number));
return true;
}
public boolean cartsub(int id, int number) {
for (int i = 0; i < itemList.size(); i++) {
if (itemList.get(i).getId() == id) {
itemList.get(i).decrease(number);
return true;
}
}
return false;
}
public void showCart() {
for (cartItem e : itemList) {
System.out.println(e);
}
}
public void cleanCart() {
itemList.clear();
}
}
主函数
package shopping;
import java.math.BigDecimal;
import java.util.Scanner;
import display.Ui;
import shop.Book;
import shop.Clothes;
import shop.Commodity;
import shop.Food;
import shop.Mall;
import shop.ShelfDao;
import shop.ShelfDaoImpl;
import shop.ShoppingCartDao;
import shop.ShoppingCartDaoImpl;
public class Main {
public static void main(String[] args) {
// Mall.showList();
Commodity x1 = new Food(0, "苹果", new BigDecimal("13"), "30days");
Commodity x2 = new Book(1, "小王子", new BigDecimal("130"), "Unknown", "Xinhua");
Commodity x3 = new Clothes(2, "衬衫", new BigDecimal("30"), "XL", "Nike");
Commodity x4 = new Food(1, "苹果", new BigDecimal("13"), "30days");// 累加
Commodity x5 = new Food(3, "奶茶", new BigDecimal("15"), "2h");
Commodity x6 = new Book(4, "《眠狂四郎》", new BigDecimal("100"), "Leo Tolstoy", "Xinhua");
Commodity x7 = new Food(5, "牛奶", new BigDecimal("3"), "20min");
ShoppingCartDao cart = new ShoppingCartDaoImpl();
ShelfDao shelf = new ShelfDaoImpl();
// 加入货架
shelf.addCommodity(x1);
shelf.addCommodity(x2);
shelf.addCommodity(x3);
shelf.addCommodity(x4);
shelf.addCommodity(x5);
shelf.addCommodity(x6);
shelf.addCommodity(x7);
Scanner choose = new Scanner(System.in);
Scanner search = new Scanner(System.in);
Scanner goodsId = new Scanner(System.in);
Scanner pause = new Scanner(System.in);// 暂停参数
String Pause = null;
access: while (true) {
Ui.mainUi();
System.out.println("请输入选项：");
int Choose = choose.nextInt();
switch (Choose) {
case 1:
shelf.showCommodity();// 显示商品
System.out.println("是否进行购买?[是（1）/否（0）]");
Choose = choose.nextInt();
if (Choose == 1) {
Mall.buyGoods(goodsId);
}
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 2:
// 商品查询ID
int flag = 1;
while (flag > 0) {
System.out.println("请输入商品ID:");
int id = search.nextInt();
if (shelf.idSearch(id) == null) {
System.out.println("没有找到该商品！");
System.out.println("是否继续查询?");
flag = search.nextInt();
} else {
System.out.print("是否添加到购物车？[是（1）/否（0）] ：");
int chioce = search.nextInt();
if (chioce == 1) {
System.out.print("添加数量？：");
int number = search.nextInt();
if (cart.cartAdd(shelf.idSearch(id), number))
System.out.println("添加成功！");// 在购物车单中添加商品
else
System.out.println("添加失败！");
}
System.out.println("是否继续查询?[是（1）/否（0）] ：");
flag = search.nextInt();
}
}
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 3:
// 商品查询Name
flag = 1;
while (flag > 0) {
System.out.println("请输入关键词:");
String name = search.next();
if (!shelf.nameSearch(name)) {
System.out.println("没有找到与" + name + "相关的商品");
System.out.println("是否继续查询?[是（1）/否（0）] ：");
flag = search.nextInt();
} else {
System.out.println("是否继续查询?[是（1）/否（0）] ：");
flag = search.nextInt();
}
}
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 4:
// 商品删除
System.out.println("请输入您需要删除的商品的对应ID:");
int choiceGoodsId = goodsId.nextInt();
System.out.println("请输入您需要减少的商品的数量:");
int choiceSubNumber = goodsId.nextInt();
if (cart.cartsub(choiceGoodsId, choiceSubNumber))
System.out.println("删除商品成功！");// 在购物车单中添加商品
else
System.out.println("删除商品失败！");
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 5:
// 查看购物车
cart.showCart();
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 6:
// 购物车清空
cart.cleanCart();
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 7:
// 购物车预结算
cart.showCart();
System.out.println("<按回车返回主界面>");
Pause = pause.nextLine();
break;
case 0:
break access;
}
for (int i = 0; i < 25; i++)
System.out.println();
}
choose.close();
search.close();
goodsId.close();
pause.close();
Ui.endUi();
}
}
