Java学习笔记7（简易的超市库存管理系统示例）

用以前学过的知识，可以简单地做一个超市库存管理系统：

定义一个商品类：

public class FruitItem {
    int ID;
    String name;
    double price;
    int number;
    double money;
}

然后：

import java.util.ArrayList;
import java.util.Scanner;

public class Shop {

    public static void main(String[] args) {
        ArrayList<FruitItem> array = new ArrayList<FruitItem>();
        init(array);
        while (true) {
            mainMenu();
            int choose = chooseFunction();
            switch (choose) {
            case 1:
                showFruitList(array);
                break;
            case 2:
                addFruit(array);
                break;
            case 3:
                deleteFruit(array);
                break;
            case 4:
                updateFruit(array);
                break;
            case 5:
                return;
            default:
                System.out.println("输入的序号不存在");
                break;
            }
        }
    }

    public static void updateFruit(ArrayList<FruitItem> array){
        System.out.println("您选择的是修改功能");
        System.out.println("请输入商品编号：");
        Scanner sc = new Scanner(System.in);
        int ID = sc.nextInt();
        for (int i = 0; i < array.size(); i++) {
            FruitItem item =array.get(i);
            if(item.ID==ID){
                System.out.println("请输入新的商品编号：");
                item.ID = sc.nextInt();
                System.out.println("请输入新的商品名称：");
                item.name = sc.next();
                System.out.println("请输入新的商品价格：");
                item.price = sc.nextDouble();
                System.out.println("商品修改成功");
                return;
            }
        }
        System.out.println("您输入的编号不存在");
    }
    
    public static void deleteFruit(ArrayList<FruitItem> array){
        System.out.println("您选择的是删除功能");
        System.out.println("请输入商品的编号：");
        Scanner sc = new Scanner(System.in);
        int ID = sc.nextInt();
        for (int i = 0; i < array.size(); i++) {
            FruitItem item = array.get(i);
            if(item.ID == ID){
                array.remove(i);
                System.out.println("删除成功");
                return;
            }
        }
        System.out.println("您输入的编号不存在");
        
    }
    
    public static void addFruit(ArrayList<FruitItem> array) {
        System.out.println("您选择的是添加商品功能");
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入商品的编号：");
        int ID = sc.nextInt();
        System.out.println("请输入商品的名字：");
        String name = sc.next();
        System.out.println("请输入商品的单价：");
        double price = sc.nextDouble();
        FruitItem item = new FruitItem();
        item.ID = ID;
        item.name = name;
        item.price = price;
        array.add(item);
    }

    public static void showFruitList(ArrayList<FruitItem> array) {
        System.out.println();
        System.out.println("==========商品库存清单==========");
        System.out.println("商品编号        商品名称        商品单价");
        for (int i = 0; i < array.size(); i++) {
            FruitItem item = array.get(i);
            System.out.println(item.ID + "        " + item.name + "        " + item.price);
        }
    }

    public static void init(ArrayList<FruitItem> array) {
        FruitItem f1 = new FruitItem();
        f1.ID = 9527;
        f1.name = "香蕉";
        f1.price = 3.0;
        FruitItem f2 = new FruitItem();
        f2.ID = 9008;
        f2.name = "苹果";
        f2.price = 5.6;
        FruitItem f3 = new FruitItem();
        f3.ID = 9879;
        f3.name = "橘子";
        f3.price = 6.6;
        array.add(f1);
        array.add(f2);
        array.add(f3);
    }

    public static void mainMenu() {
        System.out.println();
        System.out.println("==========欢迎光临某某超市==========");
        System.out.println("1：货物清单    2：添加货物    3：删除货物    4：修改货物    5：退出");
        System.out.println("请您输入要操作的功能序号");
    }

    public static int chooseFunction() {
        Scanner sc = new Scanner(System.in);
        return sc.nextInt();
    }
}