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import java.util.ArrayList;
import java.util.Scanner;
 
public class Fri_Demo {
 
 
    public static void main(String[] args) {
 
        ArrayList<FruitItem> list = new ArrayList<>();//所有商品的集合
 
        InitFriSystem();
 
        choose(list);
 
    }
 
    public static void InitFriSystem(){
 
//                - 3.1.库存货物查询
//                - 3.2.添加新货物
//                - 3.3.删除货物
//                - 3.4.修改货物
//                - 3.5.退出系统,结束main方法的运行
        System.out.println("======欢迎进入商品管理系统=======");
        System.out.println("======1.库存货物查询=======");
        System.out.println("======2.添加新货物=======");
        System.out.println("======3.删除货物=======");
        System.out.println("======4.修改货物=======");
        System.out.println("======5.退出系统=======");
 
    }
 
    public static void  FruitItemSelect(ArrayList<FruitItem> list){
 
 
        for (int i=0;i<list.size();i++){
 
            FruitItem fruitItem = list.get(i); //货物对象
//            private int ID; //商品编号
//
//            private String name; //商品名称
//
//            private double price; //商品单价
//
//            private double number; //商品数量
//
//            private double money; //商品金额
            System.out.println("货物的商品编号"+fruitItem.getID()+"名称是:"+fruitItem.getName()+"单价是:"+fruitItem.getPrice()+"" +
                    "数量是:"+fruitItem.getNumber()+"金额是:"+fruitItem.getMoney());
 
        }
 
    }
 
    public static void AddItems(ArrayList<FruitItem> list){
        Scanner scanner = new Scanner(System.in);//alt  enter
        //默认每次添加一个商品进去
        FruitItem fruitItem = new FruitItem();
        System.out.println("请输入商品编号是:");
        int ID = scanner.nextInt();
        System.out.println("请输入商品名称是:");
        String name = scanner.next();
        System.out.println("请输入商品单价是:");
        double price = scanner.nextDouble();
        System.out.println("请输入商品数量是:");
        double number = scanner.nextDouble();
        System.out.println("请输入商品金额是:");
        double money = scanner.nextDouble();
 
        fruitItem.setID(ID);
        fruitItem.setName(name);
        fruitItem.setPrice(price);
        fruitItem.setNumber(number);
        fruitItem.setMoney(money);
 
 
        list.add(fruitItem);
 
        System.out.println("商品添加完成");
 
    }
 
    public static void DeleteItems(ArrayList<FruitItem> list){
        System.out.println("请输入你要删除的商品的编号是:");
 
        Scanner scanner = new Scanner(System.in);
 
        int ID = scanner.nextInt();
 
        //我们从键盘上读取到要删除的货物的ID   要去存储货物的list去查询ID当前输入的Id的这个货物对象
        for(int i=0;i<list.size();i++){
 
            if(list.get(i).getID()==ID){
 
                list.remove(i);
 
            }
 
        }
 
 
    }
 
    public static void UpdateItems(ArrayList<FruitItem> list){
 
        System.out.println("请输入你要修改的商品的编号是:");
 
        Scanner scanner = new Scanner(System.in);
 
        int ID = scanner.nextInt();
        System.out.println("请输入你要修改的商品名称是:");
        String name = scanner.next();
        System.out.println("请输入你要修改的商品单价是:");
        double price = scanner.nextDouble();
        System.out.println("请输入你要修改的商品数量是:");
        double number = scanner.nextDouble();
        System.out.println("请输入你要修改的商品金额是:");
        double money = scanner.nextDouble();
 
        FruitItem fruitItem = new FruitItem();
 
        fruitItem.setID(ID);
        fruitItem.setName(name);
        fruitItem.setPrice(price);
        fruitItem.setMoney(money);
        fruitItem.setNumber(number);
 
        for(int i=0;i<list.size();i++){
 
            if(list.get(i).getID()==ID){
 
                list.set(i,fruitItem);
                System.out.println("恭喜你修改成功了");
 
            }
 
        }
 
    }
 
    public static void choose(ArrayList<FruitItem> list){
 
        Scanner scanner = new Scanner(System.in);
 
        while (true){
 
            int choose = scanner.nextInt();
 
            switch (choose){
                case 1:
                    //1.库存货物查询
                    FruitItemSelect(list);
                    break;
                case 2:
                    //2.添加新货物
                    AddItems(list);
                    break;
                case 3:
                    //3.删除货物
                    DeleteItems(list);
                    break;
 
                case 4:
                    // 4.修改货物
                    UpdateItems(list);
                    break;
                case 5:
                    System.exit(0);
                    break;
                default:
 
                    System.out.println("错误命令");
                    return;
 
            }
 
        }
        
    }
}

原文链接:https://blog.csdn.net/qq_28943665/article/details/109747925