Java实现简单商品管理系统

需求如下

• 查看全部商品：

  • 展示出所有的商品信息

• 添加商品：

  • 键盘录入商品信息，封装为商品对象，并存入集合

  • 需要检查商品号码是否存在，保证商品号唯一

• 删除商品：

  • 根据商品号码进行删除

  • 如果商品号不存在要给出提示

• 修改商品

  • 根据商品号码做修改

  • 如果商品号不存在要给出提示

• 查询单个商品

  • 根据商品查询

• 输入错误

  • 输入的命令不是 1 ~ 6 ，给出错误提示并继续输入

代码实现

Goods.java

package com.project.goodsManager;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class Goods {

    private int id;
    private String name;
    private double price;
    private String number;
    private GoodsType type;
    private String introduction;

    @Override
    public String toString() {
        return "Goods{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                ", number='" + number + '\'' +
                ", type=" + type +
                ", introduction='" + introduction + '\'' +
                '}' + "\n";
    }
}

GoodsOperator.java

package com.project.goodsManager;

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

public class GoodsOperator{

    private static final ArrayList<Goods> list = new ArrayList<>();
    static {
        list.add(new Goods( 1, "phone", 500, "10", GoodsType.ELECTRIC, "phone"));
        list.add(new Goods( 2, "knife", 15, "10", GoodsType.TOOL, "ipad"));
        list.add(new Goods( 3, "juice", 8.5, "100", GoodsType.FOOD, "food"));
        list.add(new Goods( 4, "sweater", 10, "100", GoodsType.CLOTH, "cloth"));
        list.add(new Goods( 5, "paper", 20, "100", GoodsType.OTHER, "other"));
    }
    public static void main(String[] args){

        boolean flag = false;
        Scanner sc = new Scanner(System.in);

        while (!flag){

            menu();
            System.out.println("请输入你的选择：");
            try {
                int choice = sc.nextInt();
                flag = true;
                judgment(choice);
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);

            }finally {
                main(null);
            }
        }
    }
    public  static void menu(){

        System.out.println("-----------------------------");
        System.out.println("---------1.查看全部商品---------");
        System.out.println("---------2.添加商品------------");
        System.out.println("---------3.删除商品------------");
        System.out.println("---------4.修改商品------------");
        System.out.println("---------5.查询商品------------");
        System.out.println("---------6.退出---------------");
        System.out.println("-----------------------------");

    }

    private  static void judgment(int choice){

        try {
            if (choice <= 0 || choice >=7){
                throw new CustomException("输入异常！");
            }else {

                switch (choice){
                    case 1 :
                        showAll();
                        break;
                    case 2 :
                        addGoods();
                        break;
                    case 3 :
                        deleteGoods();
                        break;
                    case 4 :
                        updateGoods();
                        break;
                    case 5 :
                        queryGoods();
                        break;
                    case 6 :
                        System.out.println("退出");
                        System.exit(0);
                }
            }
        } finally {
            main( null);
        }
    }
    private static void queryGoods() {

        Scanner sc = new Scanner(System.in);
        System.out.println("请输入要查询的商品编号：");
        int id = 0;
        try {
            id = sc.nextInt();
            for (Goods goods : list) {
                if (goods.getId() == id){
                    System.out.println(goods);
                    System.out.println("查询成功！");
                    return;
                }
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        System.out.println("没有此商品!");
    }

    private static void updateGoods() {

        Scanner sc = new Scanner(System.in);
        System.out.println("请输入要修改的商品号：");
        final int len = list.size();
        int id;
        try {
            id = sc.nextInt();
            for (int i = 0;i<idMax();i++){
                if (list.get(i).getId() == id){
                    list.remove(i);
                    add();
                    System.out.println("修改成功！");
                    return;
                }
            }
        } catch (Exception e) {

            e.printStackTrace();
            throw new RuntimeException(e);
        }
        System.out.println("没有此商品!");
        updateGoods();

    }

    private static void deleteGoods() {

        Scanner sc = new Scanner(System.in);
        System.out.println("请输入要删除的商品号：");
        int id;
        try {
            id = sc.nextInt();
            for (int i = 0;i <= idMax();i++){
                if (list.get(i).getId() == id){
                    list.remove(i);
                    System.out.println("删除成功！");
                    main(null);
                }
            }
        } catch (Exception e) {

            e.printStackTrace();
            throw new RuntimeException(e);


        }finally {
            System.out.println("没有此商品!");
            deleteGoods();
        }

    }

    private static void addGoods() {
        add();
        System.out.println("添加成功！");
    }

    private static void showAll() {

        System.out.println(list);
    }

    private static void add(){

        Scanner sc = new Scanner(System.in);
        int id;
        while (true) {
            try {
                id = idExist();
                if (id <=0){
                    throw new CustomException("输入有误！");
                }else {
                    break;
                }
            } catch (Exception e){
                e.printStackTrace();
            }
        }
        System.out.println("请输入商品名称：");
        String name = sc.next();
        System.out.println("请输入商品价格：");
        double price = sc.nextDouble();
        System.out.println("请输入商品数量：");
        String number = sc.next();
        System.out.println("请输入商品类型,从以下类型中选一输入：");
        System.out.println("FOOD,ELECTRIC,CLOTH,TOOL,OTHER");
        String type = sc.next();
        System.out.println("请输入商品介绍：");
        String introduction = sc.next();
        Goods goods = new Goods(id, name, price, number, GoodsType.valueOf(type), introduction);
        list.add(goods);
    }

    public static int idMax(){

        int max = list.getFirst().getId();
        for (Goods goods : list) {
            if (goods.getId() > max) {
                max = goods.getId();
                break;
            }
        }

        return Math.max(max, list.size());
    }

    public static int idExist(){

        Scanner sc = new Scanner(System.in);
        int num;
        try {
            System.out.println("请输入商品编号：");
            num = sc.nextInt();

            for (Goods goods : list){
                if (goods.getId() == num){
                    System.out.println("该商品编号已存在，请重新输入！");
                    return -1;
                }
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return num;
    }

}

GoodsType.java

package com.project.goodsManager;

public enum GoodsType {

    FOOD,
    ELECTRIC,
    CLOTH,
    TOOL,
    OTHER
}

CustomException.java

package com.project.goodsManager;

public class CustomException extends RuntimeException {

    public CustomException(String message) {
        super(message);
    }
}

GoodsText.java

package com.project.goodsManager;

public class GoodsText {
    public static void main(String[] args) {

        GoodsOperator.main(null);
    }
}

总结

1.欢迎交流

2.在Goods中选用了lombok

3.输入校验写了很多重复的代码，是可以单独抽出来作为代理

4.在判断商品编号id不能重复上，本人用了简单的自定义异常+循环来实现，这个可以用HashMap来实现

5.已将需求变为根据商品编号id来查询商品信息，这样增删改查都要对商品编号id来进行一个校验，就可以抽出一个GoodsId接口，然后让GoodsOperator来实现该接口（未实现）

6.欢迎指教