Article第一部分
public class Article {

    public String name; //商品名称
    public int amount; //商品库存数量
    public double price; //商品价格
    public int number; //商品售出数量
    public void setArticle(String mingzi,int kucun, double danjia,int xiaoshou){
        name = mingzi;
        amount = kucun;
        price = danjia;
        number = xiaoshou;
    }

    public void print(int index) {
        System.out.println(index + "\t" + name + "\t" + price + "\t" + amount + "\t" +number);
    }
}

ArticleSet 第二部分
public class ArticleSet {
    // 仓库存储商品 因此 数组的类型就是商品Article
    Article []articles = new Article[100];

}

ArticleMange 第三部分
public class ArticleMange<flag> {
        //按照仓库模板创建一个是实体的仓库对象
        ArticleSet articleSet = new ArticleSet();

        //往仓库存储一些商品
        public void initial(){
            //创建一个商品
            Article xiaoMi12 = new Article();
            xiaoMi12.setArticle("小米12",3,999,0);

            //再创建一个商品
            Article iphone12 = new Article();
            iphone12.setArticle("苹果12",9999,7888,12);

            //再创建一个商品
            Article huawei = new Article();
            huawei.setArticle("华为手机",666,2888,20);

            articleSet.articles[0] = xiaoMi12;
            articleSet.articles[1] = iphone12;
            articleSet.articles[2] = huawei;

        }

        //启动菜单

    public void startMenu() {
        boolean flag = true;
        do {
            System.out.println("欢迎使用前台商城管理系统");
            System.out.println("*********************************");
            System.out.println("1.查看商品信息");
            System.out.println("2.新增商品信息");
            System.out.println("3.删除商品信息");
            System.out.println("4.卖出商品信息");
            System.out.println("5.商品销售排行榜");
            System.out.println("6.退出");
            System.out.println("*********************************");
            System.out.println("请选择要执行的操作：");
            Scanner scanner = new Scanner(System.in);

            int num = scanner.nextInt();
            switch (num) {
                case 1:
                    System.out.println("查看商品信息");
                    chakan();
                    break;
                case 2:
                    System.out.println("新增商品信息");
                    add();
                    break;
                case 3:
                    System.out.println("删除商品信息");
                    delete();
                    break;
                case 4:
                    System.out.println("卖出商品");
                    sell();
                    break;
                case 5:
                    System.out.println("商品销售排行榜");
                    paihangbang();
                    break;
                case 6:
                    System.out.println("谢谢使用");
                    flag = false;
                    exit();
                    break;
                default:
                    System.out.println("你输入错误，请再次输入");
            }


        } while (flag);

    }


    private void chakan() {
        System.out.println("编号 \t 名字 \t 单价 \t 库存 \t 已售");
        for (int i = 0;i<articleSet.articles.length;i++){
            if(articleSet.articles[i] !=null){
                articleSet.articles[i].print(i+1);

            }
        }

    }
    private void add() {
        Scanner scanner =  new Scanner(System.in);
        System.out.println("请输入商品的名称");
        String name = scanner.next();
        System.out.println("请输入价格");
        double price = scanner.nextDouble();
        System.out.println("请输入库存");
        int count = scanner.nextInt();
        System.out.println("请输入一卖的数量");
        int number = scanner.nextInt();

        Article newArticle = new Article();
        newArticle.setArticle(name, (int) price,count,number);


        for (int i = 0; i<articleSet.articles.length;i++) {


            if (articleSet.articles[i] == null) {
                articleSet.articles[i] = newArticle; // 把新建的对象放在数组中的第一个空位置
                break; // 后续的空位置直接跳过
            }
        }

    }
    private void delete() {
        System.out.println("请输入要删除的商品编号");
        Scanner scanner=new Scanner(System.in);
        int bianhao=scanner.nextInt();
        boolean flag =true;
        for (int i=0; i<articleSet.articles.length;i++) {
            if (articleSet.articles[i] != null && (i + 1) == bianhao) {
                int j = i;
                while (articleSet.articles[j + 1] != null) {
                    //后面元素向前移动
                    articleSet.articles[j] = articleSet.articles[j + 1];
                    j++;
                }
                articleSet.articles[j] = null;
                flag = true;
                break; //后面的空数组元素没有必要执行


            } else {
                flag = false;
            }

        }

    }

    private void sell() {
        System.out.println("请输入购买商品的名称：");
       Scanner scanner= new Scanner(System.in);
       String name = scanner.next();
       for(int i = 0;i < articleSet.articles.length; i ++){
           if((articleSet.articles[i].name).equals(name)){   //在数组的有值的元素中 找到售出商品名字相同的位置
               System.out.println("输入卖出数量：");
               int shuliang = scanner.nextInt();
               if(shuliang < articleSet.articles[i].amount){
                   articleSet.articles[i].amount = articleSet.articles[i].amount - shuliang;
                   articleSet.articles[i].number = articleSet.articles[i].number + shuliang;
               }
               System.out.println("售卖成功！");
               break;
           }
       }
    }
        //排序（冒泡排序）
    private void paihangbang() {

        for (int i = 0;i < articleSet.articles.length - 1;i ++){
            for (int j = 0;j<articleSet.articles.length-i-1;j++){
                if(articleSet.articles[j] !=null && articleSet.articles[j+1] != null){  //数组中不为null才能参与排序
                    if (articleSet.articles[j].number < articleSet.articles[j+1].number){
                        Article newTemp = articleSet.articles[j];  //新定义一个临时变量，实现两个数据交换位置
                        articleSet.articles[j] = articleSet.articles[j+1];
                        articleSet.articles[j+1] = newTemp;
                    }
                }
            }
        }
        for(int i = 0;i < articleSet.articles.length;i++){
            if(articleSet.articles[i] !=null){
                System.out.println((i+1) + "\t" + articleSet.articles[i].name + "\t" + articleSet.articles[i].number);
            }
        }

    }
    private void exit() {
            System.out.println("操作结束，即将退出程序");
    }

}

test 第四部分
public class test {
    public static void main(String[] args) {
        ArticleMange articleMange = new ArticleMange();
        articleMange.initial();
        articleMange.startMenu();
    }
}