package shangpin;

public class Goods {
    private String id;//商品编号
    private String name;//名称
    private double price;//价格
    private String miaoshu;//描述

    @Override
    //重写toString
    public String toString() {
        return "商品信息:"+id+","+name+","+price+","+miaoshu;
    }

    public Goods(String id, String name, double price, String miaoshu) {
        this.id = id;
        this.name = name;
        this.price = price;
        this.miaoshu = miaoshu;
    }

    public String getId() {
        return id;
    }

    public void setId(String 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 String getMiaoshu() {
        return miaoshu;
    }

    public void setMiaoshu(String miaoshu) {
        this.miaoshu = miaoshu;
    }
}

package shangpin;

import java.util.List;

public class Zsgc {
    //添加，删除，修改，单查询，展示全查
    //添加(上架商品)
    public static boolean add(Goods go, List<Goods> dd){
        boolean f = true;
        for (Goods bianhao : dd){
            if (go.getId().equals(bianhao.getId())){
                f = false;
                break;
            }
        }
        if (f){
            dd.add(go);
        }
        return f;
    }

    //修改(调整价格)
    public static boolean modify(Goods go,List<Goods> dd){
        boolean f = false;
        for (Goods bianhao : dd){
            if (go.getId().equals(bianhao.getId())){
                f = true;
                bianhao.setName(go.getName());
                bianhao.setPrice(go.getPrice());
                bianhao.setMiaoshu(go.getMiaoshu());
                break;
            }
        }
        return f;
    }

    //删除(下架商品 )
    public static boolean delete(String id,List<Goods> dd){
        boolean f = false;
        for (Goods bianhao : dd){
            if (bianhao.getId().equals(id)){
               dd.remove(bianhao);
               f = true;
               break;
            }
        }
        return f;
    }

    //单查
    public static Goods select(String id,List<Goods> dd){
        Goods g = null;
        for (Goods bianhao : dd){
            if (bianhao.getId().equals(id)){
                g = bianhao;
                break;
            }
        }
        return g;
    }

    //展示(商品列表)
    public static void show(List<Goods> dd){
        for (Goods bianhao : dd){
            System.out.println(bianhao);
        }
    }
}

package shangpin;

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

public class Spin {
    //添加静态字段
    static List<Goods> dd = new ArrayList<Goods>();
    static Scanner read = new Scanner(System.in);

    public static void main(String[] args) {
        dd.add(new Goods("11","汽水",3,"气泡水"));
        dd.add(new Goods("12","饼干",8,"饿了就吃"));
        dd.add(new Goods("13","辣条",5,"卫龙"));

        //定义数据类型
        int n = 0;
        String id,name,miaoshu;
        double price;
        Goods g;
        boolean f;

        do {
            System.out.println("欢迎使用999商品管理系统");
            System.out.println("---商品列表请输入:1---");
            System.out.println("---上架商品请输入:2---");
            System.out.println("---下架商品请输入:3---");
            System.out.println("---调整商品请输入:4---");
            System.out.println("---单查某个商品请输入:5---");
            System.out.println("---退出:0----");
            System.out.print("请选择:");

            n = read.nextInt();
            switch (n) {
                case 1:
                    System.out.println("所有商品列表为：");
                    System.out.println("-------编号 名称 价格 描述");
                    Zsgc.show(dd);
                    break;
                case 2:
                    System.out.println("请输入新商品编号:");
                    id = read.next();
                    System.out.println("请输入新商品名称:");
                    name = read.next();
                    System.out.println("请输入新商品价格:");
                    price = read.nextDouble();
                    System.out.println("请输入新商品描述:");
                    miaoshu = read.next();

                    g = new Goods(id,name,price,miaoshu);
                    f = Zsgc.add(g,dd);
                    if (f) {
                        System.out.println("上架成功");
                    }else {
                        System.out.println("上架失败");
                    }
                    break;
                case 3:
                    System.out.println("请输入要删除的商品编号:");
                    id = read.next();
                    f = Zsgc.delete(id,dd);
                    if (f){
                        System.out.println("删除成功");
                    }else {
                        System.out.println("删除失败");
                    }
                    break;
                case 4:
                    System.out.println("请输入要修改的商品编号");
                    id = read.next();
                    System.out.println("请输入要修改的商品名称");
                    name = read.next();
                    System.out.println("请输入要修改的商品价格");
                    price = read.nextDouble();
                    System.out.println("请输入要修改的商品描述");
                    miaoshu = read.next();

                    g = new Goods(id,name,price,miaoshu);
                    f = Zsgc.modify(g,dd);
                    if (f) {
                        System.out.println("修改成功");
                    }else {
                        System.out.println("修改失败");
                    }
                    break;
                case 5:
                    System.out.println("请输入要查询的商品编号");
                    id = read.next();
                    g = Zsgc.select(id,dd);
                    if (g != null){
                        System.out.println(g);
                    }else {
                        System.out.println("没有此商品");
                    }
                    break;

            }
        }while (n != 0);
    }
}

运行结果: