Java初学之ArrayList实现购物车的增删查改

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Scanner;
/**
 * 购物车系统
 * @author com
 *
 */
public class ListShopping {
	static Scanner sc = new Scanner(System.in);
	static ArrayList list = new ArrayList<>();
	public static void main(String[] args) {
		 manu();
	}
	public static void manu() {
		System.out.println("**********************菜单***********************");
		System.out.println("  1.添加   2.修改数量  3.删除商品  4、查询全部  5.退出");
		System.out.println("*************************************************");
		while(true) {
			System.out.print("* 输入选择：");
			int in = sc.nextInt();
			if(in == 1) add();
			if(in == 2) updata();
			if(in == 3) delete();
			if(in == 4) query();
			if(in == 5) exit();
		}
	}
	/**
	 * 1.添加
	 */
	public static void add() {
		System.out.print("* 输入编号：");
		int id = sc.nextInt();
		System.out.print("* 输入名称：");
		String name = sc.next();
		System.out.print("* 输入价格：");
		Double price = sc.nextDouble();
		System.out.print("* 输入数量：");
		int amount = sc.nextInt();
		Commodity com = new Commodity(id,name,price,amount);
		list.add(com);
	}
	/**
	 * 2.修改
	 */
	public static void updata() {
		System.out.print("* 输入要修改的编号：");
		int id = sc.nextInt();
		System.out.print("* 输入新的数量：");
		int amount = sc.nextInt();
		boolean bool = true;
		for(int i=0;i it = list.iterator();
		while(it.hasNext()) {
			System.out.println(it.next());
		}
//		for(Commodity com:list) {
//			System.out.println(com.getId()+"\t"+com.getName()+"\t"+com.getPrice()+"\t"+com.getAmount());
//		}
		System.out.println("查询成功：");
	}	
	/**
	 * 5.退出
	 */
	public static void exit() {
		System.out.print("* y(是) n(否) 确认退出：");
		String in = sc.next();
		if(in.equals("y")) {
			System.exit(0);
		}else if(in.equals("n")) {
			return;
		}else {
			System.out.println("输入错误！！！");
		}
	}
}
/**
 * 商品类
 * @author com
 *
 */
class Commodity {
	private int id;
	private String name;
	private double price;
	private int amount;
	
	Commodity(int id,String name,double price,int amount){
		this.id = id;
		this.name = name;
		this.price = price;
		this.amount = amount;
	}
	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;
	}
	public int getAmount() {
		return amount;
	}
	public void setAmount(int amount) {
		this.amount = amount;
	}
	@Override
	public String toString() {
		return id+"\t"+name+"\t"+price+"\t"+amount;
	}
}