1.前期調查、

• 可以在此直接搜尋商品

• 選擇對應商品加入購物車

• 購物車面板

• 刪除商品

2.系統功能結構圖

3.UML類圖

4.本系統哪裡體現了面向物件的封裝性

package ShoppingCart;

public class Goods {
    private int id; //商品id
    private String name;//商品名稱
    private double price;//商品價格
    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 double GetPrice() {
		return price;
	}
	public void SetPrice(double price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "goods [id=" + id + ", name=" + name + ", price=" + price + "]";
	}
	public Goods(String name,double price){
		this.name=name;
		this.price=price;
	}
}

 

• 其中public、private都體現了面向物件的封裝性，private屬性私有化，通過使用private修飾符關鍵字進行修飾，外部無法直接訪問，只能通過getters來訪問。

5.專案包結構與關鍵程式碼

• 商品類

package ShoppingCart;

public class Goods {
    private int id; //商品id
    private String name;//商品名稱
    private double price;//商品價格
    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 double GetPrice() {
		return price;
	}
	public void SetPrice(double price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "goods [id=" + id + ", name=" + name + ", price=" + price + "]";
	}
	public Goods(String name,double price){
		this.name=name;
		this.price=price;
	}
}

 

package ShoppingCart;

public class Entry {
    private Goods item;
    private int number;
    private double Totalprice;
    //private ArrayList<Hash>HashList=new ArrayList<>();//商品陣列
	public Goods GetItem() {
		return item;
	}
	public void SetItem(Goods item) {
		this.item = item;
	}
	public int GetNumber() {
		return number;
	}
	public void SetNumber(int number) {
		this.number = number;
		SetTotalprice();
	}
	public double GetTotalprice() {
		return Totalprice;
	}
	public void SetTotalprice() {
		Totalprice = item.GetPrice()*number;
	}
	@Override
	public String toString() {
		return "entry [item=" + item + ", number=" + number + ", totalprice=" + Totalprice + "]";
	}
	public Entry(Goods item,int number) {
		this.item=item;
		this.number=number;
		SetTotalprice();
	}
	
}

 

• 購物車類

package ShoppingCart;

import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
public class Cart {
	HashMap<Integer,Entry> mp=new HashMap<>();//id,entry
	private ArrayList<Hash>HashList=new ArrayList<>();//判斷id
	public void AddGoods(int key,Entry item) {
		if(mp.containsKey(key)){
			//存在則增加數量
			mp.get(key).SetNumber(mp.get(key).GetNumber()+item.GetNumber());//原來的數量+新增的數量
		} else {
			Hash temp=new Hash();
			temp.key=key;
			temp.name=item.GetItem().GetName();
			HashList.add(temp);
			mp.put(key,item);//不存在則增加商品
			mp.get(key).GetItem().SetId(key);//置id
		}
	}
	public boolean ModifyNumber(int key,int number){//修改商品的數量
		if(!mp.containsKey(key))
			return false;
		mp.get(key).SetNumber(number);//修改數量
		return true;
	}
	public boolean DeleteGoods(int number) {//刪除某種商品
		if(mp.containsKey(number))
			mp.remove(number);
		else 
			return false;
		return true;
	}
	
	public void ShowAll(){//檢視訂單資訊
	    Collection<Entry> goods = mp.values();
	    Iterator<Entry> iterator = goods.iterator();
	    while(iterator.hasNext()){
	        Entry productItem = iterator.next();
	        Goods product = productItem.GetItem();
	        System.out.println("商品ID："+product.GetId()+",商品名稱："+product.GetName()+",單價："+product.GetPrice()
	        +",數量："+productItem.GetNumber()
	                +",小計："+productItem.GetTotalprice());
	        }
	 }
	public void GetTotalPrice() {
		Collection<Entry> goods = mp.values();
        Iterator<Entry> iterator = goods.iterator();
        double total=0;
        while(iterator.hasNext()){
            Entry productItem = iterator.next();
            total+=productItem.GetTotalprice();
	        }
        System.out.println("當前購物車總價格為:"+total+"元");
        //return total;
	}
	public void clearcart() {//清空購物車
		mp.clear();
	}
	//@SuppressWarnings("unlikely-arg-type")
	public String GetUid(Entry pro){//判斷是否出現過
		 for(int i=0;i<HashList.size();i++) {
			 if(HashList.get(i).name.equals(pro.GetItem().GetName()))
				 return String.valueOf(HashList.get(i).key);
		 }
		 StringBuffer now = new StringBuffer(new SimpleDateFormat("yyyyMMdd").format(new Date()));
		 int n = (int)(Math.random() * 9000.0D + 1000.0D);
		 return now.append(n).toString().substring(4);// "202110063548"
	}
}

• 新增商品
  

• 刪除商品