【项目实战】太强大了，Java外卖点餐初级系统【附源码】

傻瓜式外卖点餐系统------(无数据库)

tips：

菜品类(菜品id，菜品名，菜品类型，上架时间，单价，月销售，总数量)
管理员类(管理员id，账号，密码)
客户类(客户id，客户名，性别，密码，送餐地址，手机号，创建时间)
订单类(订单号，订单创建时间，菜品id，购买数，客户id，总价格，订单状态)
说明：

菜品类型可自行设计数据类型(int或String)，如1：面食 2：米饭 3：湘菜 …
菜品上架时间、客户创建时间、订单创建时间根据添加时间自动分配系统时间
订单状态类型为int（0:未支付 1：已支付 2：配送中 3：已完成）
要求实现如下功能：
实现不同角色用户登录系统
(1) 管理员登录系统看到如下菜单：
① 添加菜品
② 查看所有菜品信息(包含分页功能)
③ 查看指定类别的菜品信息
④ 根据菜品id修改菜品价格
⑤ 删除指定id的菜品
⑥ 添加客户
⑦ 查看客户列表
⑧ 删除指定id的客户
⑨ 订单列表显示
⑩ 根据订单id修改订单状态
11 退出
(2) 客户登录看到如下菜单：
① 显示所有菜品(按菜品销量从高到低排序输出)
-------->点餐（输入菜品id和购买数量）
② 根据菜品类别显示所有菜品
③ 查看所有订单(当前登录用户的)
④ 修改密码（当前登录用户的）
⑤ 个人信息显示

以上就是全部要求，首先咱们可以先建一个接口，方便对四个管理类进行操作；

package com.softeem.lesson23.test2;

import java.util.List;

public interface DAO<T> {
    void insert(T t);
    T findById(String id);
    List<T> findAll();
    void delete(String id);
}

一、再根据要求，先把四个类的属性类建立起来：
1.Admin类（管理员类）

package com.softeem.lesson23.test2;

public class Admin {
    private String aID;
    private String account;
    private String apwd;
    public Admin() {
        // TODO Auto-generated constructor stub
    }
    public Admin(String aID, String account, String apwd) {
        super();
        this.aID = aID;
        this.account = account;
        this.apwd = apwd;
    }
    public String getaID() {
        return aID;
    }
    public void setaID(String aID) {
        this.aID = aID;
    }
    public String getAccount() {
        return account;
    }
    public void setAccount(String account) {
        this.account = account;
    }
    public String getApwd() {
        return apwd;
    }
    public void setApwd(String apwd) {
        this.apwd = apwd;
    }
    @Override
    public String toString() {
        return "Admin [aID=" + aID + ", account=" + account + ", apwd=" + apwd + "]";
    }

}

2.Dishes类（菜品类）

package com.softeem.lesson23.test2;

import java.time.LocalDate;

public class Dishes {
    private String dID;
    private String dname;
    private String dtype;
    private LocalDate dtime;
    private double price;
    private int dsales;
    private int dstocks;

    public Dishes() {
        // TODO Auto-generated constructor stub
    }

    public Dishes(String dID, String dname, String dtype, LocalDate dtime, double price, int dsales, int dstocks) {
        super();
        this.dID = dID;
        this.dname = dname;
        this.dtype = dtype;
        this.dtime = dtime;
        this.price = price;
        this.dsales = dsales;
        this.dstocks = dstocks;
    }

    public String getdID() {
        return dID;
    }

    public void setdID(String dID) {
        this.dID = dID;
    }

    public String getDname() {
        return dname;
    }

    public void setDname(String dname) {
        this.dname = dname;
    }

    public String getDtype() {
        return dtype;
    }

    public void setDtype(String dtype) {
        this.dtype = dtype;
    }

    public LocalDate getDtime() {
        return dtime;
    }

    public void setDtime(LocalDate dtime) {
        this.dtime = dtime;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getDsales() {
        return dsales;
    }

    public void setDsales(int dsales) {
        this.dsales = dsales;
    }

    public int getDstocks() {
        return dstocks;
    }

    public void setDstocks(int dstocks) {
        this.dstocks = dstocks;
    }

    @Override
    public String toString() {
        return "Dishes [菜品id：" + dID + ", 菜品名：" + dname + ", 菜品类型：" + dtype + ", 上架时间：" + dtime + ", 单价：" + price
                + ", 月销量：" + dsales + ", 总数量：" + dstocks + "]";
    }

}

3.Order类（订单类）

package com.softeem.lesson23.test2;

import java.time.LocalDateTime;

public class Order {
    private String OrderID;
    private LocalDateTime utime;
    private Dishes dishes;
    private int Ordernum;
    private String uID;
    private Double Orderprice;
    private int OrderValue;

    public Order() {
        // TODO Auto-generated constructor stub
    }

    public Order(String orderID, LocalDateTime utime, Dishes dishes, int ordernum, String uID, Double orderprice,
            int orderValue) {
        super();
        OrderID = orderID;
        this.utime = utime;
        this.dishes = dishes;
        Ordernum = ordernum;
        this.uID = uID;
        Orderprice = orderprice;
        OrderValue = orderValue;
    }

    public String getOrderID() {
        return OrderID;
    }

    public void setOrderID(String orderID) {
        OrderID = orderID;
    }

    public LocalDateTime getUtime() {
        return utime;
    }

    public void setUtime(LocalDateTime utime) {
        this.utime = utime;
    }

    public Double getOrderprice() {
        return Orderprice;
    }

    public void setOrderprice(Double orderprice) {
        Orderprice = orderprice;
    }

    public Dishes getDishes() {
        return dishes;
    }

    public void setDishes(Dishes dishes) {
        this.dishes = dishes;
    }

    public int getOrdernum() {
        return Ordernum;
    }

    public void setOrdernum(int ordernum) {
        Ordernum = ordernum;
    }

    public String getuID() {
        return uID;
    }

    public void setuID(String uID) {
        this.uID = uID;
    }

    public int getOrderValue() {
        return OrderValue;
    }

    public void setOrderValue(int orderValue) {
        OrderValue = orderValue;
    }

    @Override
    public String toString() {
        return "Order [OrderID=" + OrderID + ", utime=" + utime + ", dishes=" + dishes + ", Ordernum=" + Ordernum
                + ", uID=" + uID + ", Orderprice=" + Orderprice + ", OrderValue=" + OrderValue + "]";
    }

}

4.User类（用户类）

package com.softeem.lesson23.test2;

import java.time.LocalDateTime;

public class User {
    private String uID;
    private String uname;
    private String usex;
    private String upwd;
    private String uadress;
    private String utel;
    private LocalDateTime utime;

    public User() {
        // TODO Auto-generated constructor stub
    }

    public User(String uID, String uname, String usex, String upwd, String uadress, String utel, LocalDateTime utime) {
        super();
        this.uID = uID;
        this.uname = uname;
        this.usex = usex;
        this.upwd = upwd;
        this.uadress = uadress;
        this.utel = utel;
        this.utime = utime;
    }

    public String getuID() {
        return uID;
    }

    public void setuID(String uID) {
        this.uID = uID;
    }

    public String getUname() {
        return uname;
    }

    public void setUname(String uname) {
        this.uname = uname;
    }

    public String getUsex() {
        return usex;
    }

    public void setUsex(String usex) {
        this.usex = usex;
    }

    public String getUpwd() {
        return upwd;
    }

    public void setUpwd(String upwd) {
        this.upwd = upwd;
    }

    public String getUadress() {
        return uadress;
    }

    public void setUadress(String uadress) {
        this.uadress = uadress;
    }

    public String getUtel() {
        return utel;
    }

    public void setUtel(String utel) {
        this.utel = utel;
    }

    public LocalDateTime getUtime() {
        return utime;
    }

    public void setUtime(LocalDateTime utime) {
        this.utime = utime;
    }

    @Override
    public String toString() {
        return "User [uID=" + uID + ", uname=" + uname + ", usex=" + usex + ", upwd=" + upwd + ", uadress=" + uadress
                + ", utel=" + utel + ", utime=" + utime + "]";
    }

}

这一步没什么难度，直接把每一个属性都设置一下，然后设置为私有，注意属性的数据类型，这个很重要，方便后期管理类对其进行操作。
二、属性管理类
这个是整个demo比较难得地方，我的想法是建立Admin属性管理类，Order属性管理类，Dishes属性类，User属性管理类，再在Admin属性管理类里把Order属性管理类，Dishes属性类，User属性管理类先new出来，然后，每个属性管理类实现各自的方法，只需要在Admin属性管理类中调用各个属性管理类的方法，就可以实现通过Admin类管理其他类的数据，但是，每个类需要建一个Map集合，存储各自的元素，此处应该注意每个属性管理类Map的键方便后期对Map进行操作，然后建立菜单类，规定User和Admin能调用的方法。
话不多说，直接上代码，一下代码是通过Admin管理类延伸的，所以先看Admin管理类。
1.Admin管理类

package com.softeem.lesson23.test2;

import java.time.LocalDate;
import java.time.LocalDateTime;
//import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
//import java.util.Set;

public class AdminSys implements DAO<Admin> {
    static Map<String, Admin> map = new HashMap<>();
//    static Set<String> keys = map.keySet();
    UserSys u = new UserSys();
    OrderSys o = new OrderSys();
    DishesSys d = new DishesSys();
    Scanner sc = new Scanner(System.in);

    /**
     * 添加菜品
     */
    public void addDishes() {
        System.out.println("请输入您要添加的菜品:(按照:菜品ID/菜品名/菜品类型/单价/月销量/总数量)");
        String str = sc.next();
        String[] info = str.split("/");
        //
        if (info.length < 6) {
            System.out.println("天啦撸，输入失败啦，请重新输入！");
            addDishes();
        } else {
            LocalDate dtime = LocalDate.now();
            Dishes t = new Dishes(info[0], info[1], info[2], dtime, Double.parseDouble(info[3]),
                    Integer.parseInt(info[4]), Integer.parseInt(info[5]));
            d.insert(t);
            System.out.println("小主,恭喜你！添加成功了");
        }
    }

    /**
     * 查看所有菜品信息(包含分页功能)
     */
    public void showAllDishes(int pageSize) {
        List<Dishes> list = d.findAll();
        int start = 0;
        //先写一个死循环，进入else后break掉
        while (true) {
            if (list.size() > (pageSize + start)) {
                System.out.println(list.subList(start, pageSize + start));

            } else {
                System.out.println(list.subList(start, list.size()));
                break;
            }
            start = start + pageSize;
        }
    }

    /**
     * 查看指定类别的菜品信息
     * 
     */
    public void selecBytypeOfAdmin() {
        System.out.println("请输入您要查询菜品的类别：");
        String typename = sc.next();
        d.selectBytype(typename);
    }

    /**
     * 根据菜品id修改菜品价格
     */
    public void selectByDishesID() {
        System.out.println("请输入您要查询的菜品id：");
        String id = sc.next();
        Dishes dish = d.findById(id);
        if (dish == null) {
            System.out.println("没有当前id的菜品呢");
        } else {
            System.out.println("当前菜品为：" + dish);
            System.out.println("请输入新的菜品单价：");
            double newprice = sc.nextDouble();
            Dishes t = new Dishes(dish.getdID(), dish.getDname(), dish.getDtype(), dish.getDtime(), newprice,
                    dish.getDsales(), dish.getDstocks());
            d.insert(t);
            System.out.println("修改成功" + d.findById(t.getdID()));
        }
    }

    /**
     * 删除指定id的菜品
     * 
     * @param args
     */
    public void deleteDishes() {
        System.out.println("请输入您要删除的菜品id");
        String id = sc.next();
        d.delete(id);
        System.out.println("删除成功！！");
    }

    /**
     * 添加客户
     */
    public void addUser() {
        System.out.println("请输入您要添加的用户:按照(id/姓名/性别/密码/送餐地址/手机号)");
        String str = sc.next();
        String[] info = str.split("/");
        if (info.length < 6) {
            System.out.println("您输入的信息有误，请重新输入....");
            addUser();
        } else {
            LocalDateTime utime = LocalDateTime.now();
            u.insert(new User(info[0], info[1], info[2], info[3], info[4], info[5], utime));
            System.out.println("添加成功");
        }
    }

    /**
     * 查看客户列表
     */
    public void findUser() {
        List<User> userlist = u.findAll();
        for (User user : userlist) {
            System.out.println(user);
        }
    }

    /**
     * 根据id查找指定用户
     */
    public User findUserByid(String id) {
        return u.findById(id);
    }

    /**
     * 删除指定id的客户
     */
    public void deleteUserByAdmin() {
        System.out.println("请输入您要删除的id：");
        String id = sc.next();
        u.delete(id);
    }

    /**
     * 订单列表显示
     */
    public void showAllOrder() {
        List<Order> allOrder = o.findAll();
        for (Order order : allOrder) {
            System.out.println(order);
        }
    }

    /**
     * 根据订单id修改订单状态
     */
    public void changeOrderValue() {
        System.out.println("请输入您要修改状态的订单id");
        String id = sc.next();
        Order order = o.findById(id);
        if (order == null) {
            System.out.println("没有当前id的订单，请检查输入");
        } else {
            System.out.println("已找到当前id订单" + order);
            System.out.println("请输入您要修改的状态：0:未支付 1：已支付 2：配送中 3：已完成");
            int value = sc.nextInt();
            Order t = new Order(order.getOrderID(), order.getUtime(), order.getDishes(), order.getOrdernum(),
                    order.getuID(), order.getOrderprice(), value);
            o.insert(t);
            System.out.println("修改成功了！！！");
        }

    }
    /**
     * 显示所有菜品(按菜品销量从高到低排序输出)
     */
    public void showAllDishesByUser() {
        List<Dishes> list = d.findAll();
        Collections.sort(list, (p1, p2) -> p1.getDsales() - p2.getDsales());
        System.out.println(list);
    }

    /**
     * 点餐（输入菜品id和购买数量）
     */
    public void shopDishes(User user) {
        showAllDishesByUser();
        System.out.println("请输入您要购买的id和数量：按照(id/数量)");
        String str = sc.next();
        String[] info = str.split("/");
        // 判断输入是否符合要求，不符合则要求重新输入
        if (info.length < 2) {
            System.out.println("输入有误，请重新输入：");
            shopDishes(user);
        } else {
            LocalDateTime l = LocalDateTime.now();
            // String orderID, LocalDateTime utime, Dishes dishes, int ordernum, String uID,
            // Double orderprice,int orderValue
            Order t = new Order(info[0], l, d.findById(info[0]), Integer.parseInt(info[1]), user.getuID(),
                    o.findById(info[0]).getOrderprice(), o.findById(info[0]).getOrderValue());
            o.insert(t);
            System.out.println("订单已生成！！！" + o.findById(info[0]));
        }
    }

    /**
     * 根据菜品类别显示所有菜品
     */
    public void ShowOfTypeByUser() {
        System.out.println("请输入您要查找的类别：");
        String str = sc.next();
        System.out.println(d.findByType(str));

    }

    /**
     * 查看所有订单(当前登录用户的)
     */
    public void showAllOrderByUser(User user) {
        List<Order> list = o.findByuId(user.getuID());
        for (Order order : list) {
            System.out.println(order);
        }
    }

    /**
     * 修改密码（当前登录用户的）
     */
    public void changePwdByUser(User user) {
        u.changepwd(user.getuID());
        System.out.println("修改成功！！");
    }

    /**
     * 个人信息显示
     */
    public void showByUser(User user) {
        User findById = u.findById(user.getuID());
        System.out.println(findById);
    }
   //待补充功能，删除管理员
    @Override
    public void delete(String id) {

    }
  //待补充功能，添加管理员
    @Override
    public void insert(Admin t) {
        // TODO Auto-generated method stub

    }
  //待补充功能，通过id即账号查找管理员
    @Override
    public Admin findById(String id) {

        return map.get(id);
    }
  //待补充功能，显示所有管理员
    @Override
    public List<Admin> findAll() {
        // TODO Auto-generated method stub
        return null;
    }
     //先设置系统默认数据
    public void addMessage() {
        map.put("qwl", new Admin("10086", "qwl", "123456"));
        LocalDate time = LocalDate.now();
        Dishes d1 = new Dishes("1", "红烧猪蹄", "肉类", time, 12.5, 20, 30);
        d.insert(d1);
        Dishes d2 = new Dishes("2", "鸡公煲", "肉类", time, 21.5, 30, 20);
        d.insert(d2);
        Dishes d3 = new Dishes("3", "麻辣香锅", "火锅类", time, 30, 5, 10);
        d.insert(d3);
        Dishes d4 = new Dishes("4", "水煮肉片", "肉类", time, 15, 12, 15);
        d.insert(d4);
        Dishes d5 = new Dishes("5", "水果沙拉", "水果类", time, 6, 70, 60);
        d.insert(d5);
        // String orderID, LocalDateTime utime, Dishes dishes, int ordernum, String uID,
        // Double orderprice,int orderValue
        LocalDateTime localdatetime = LocalDateTime.now();
        Order o1 = new Order("1", localdatetime, d1, 10, "1001", 60.0, 1);
        o.insert(o1);
        Order o2 = new Order("2", localdatetime, d2, 5, "1002", 50.0, 10);
        o.insert(o2);
        Order o3 = new Order("3", localdatetime, d3, 5, "1003", 40.0, 5);
        o.insert(o3);
        Order o4 = new Order("4", localdatetime, d4, 5, "1004", 30.0, 6);
        o.insert(o4);
        Order o5 = new Order("5", localdatetime, d5, 5, "1005", 20.0, 8);
        o.insert(o5);
        // String uID, String uname, String usex, String upwd, String uadress, String
        // utel, LocalDateTime utime
        User u1 = new User("1001", "张三", "男", "123456", "湖北", "13545286487", localdatetime);
        u.insert(u1);
        User u2 = new User("1002", "李四", "男", "234567", "湖南", "15927948976", localdatetime);
        u.insert(u2);
        User u3 = new User("1003", "王五", "男", "345678", "江苏", "15927986854", localdatetime);
        u.insert(u3);
        User u4 = new User("1004", "刘柳", "女", "456789", "浙江", "18771580860", localdatetime);
        u.insert(u4);
        User u5 = new User("1005", "赵琦", "女", "567890", "新疆", "18771580750", localdatetime);
        u.insert(u5);
    }

}

2.Order属性管理类

package com.softeem.lesson23.test2;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

public class OrderSys implements DAO<Order> {
    static Map<String, Order> ordermap = new HashMap<>();
    static List<Order> orderlist = new ArrayList<>();
    /**
     * 新增订单
     */
    @Override
    public void insert(Order t) {
        ordermap.put(t.getOrderID(), t);

    }
    /**
     * 通过订单id查找订单
     */
    @Override
    public Order findById(String id) {
        if (ordermap.get(id) == null) {
            return null;
        } else {
            return ordermap.get(id);
        }

    }
    /**
     * 通过用户id查询用户的所有订单，并返回一个list集合
     * @param uid
     * @return
     */
    public List<Order> findByuId(String uid) {
        List<Order> list = new ArrayList<>();
        Set<String> keys = ordermap.keySet();
        for (String key : keys) {
            if (Objects.equals(uid, ordermap.get(key).getuID())) {
                list.add(ordermap.get(key));
            }
        }
        return list;
    }

    /**
     * 显示所有订单
     */
    @Override
    public List<Order> findAll() {
        Set<String> keys = ordermap.keySet();
        for (String key : keys) {
            orderlist.add(ordermap.get(key));
        }
        return orderlist;
    }
    /**
     * 待完成功能，删除订单
     */
    @Override
    public void delete(String id) {
        // TODO Auto-generated method stub

    }
}

3.User属性管理类

package com.softeem.lesson23.test2;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

//客户id，客户名，性别，密码，送餐地址，手机号，创建时间
public class UserSys implements DAO<User> {
    static Map<String, User> usermap = new HashMap<>();
    List<User> list = new ArrayList<>();
    Scanner sc = new Scanner(System.in);

    /**
     * 添加客户
     */
    @Override
    public void insert(User t) {
        usermap.put(t.getuID(), t);

    }

    /**
     * 查看客户列表
     */
    @Override
    public List<User> findAll() {
        Set<String> keys = usermap.keySet();
        for (String str : keys) {
            list.add(usermap.get(str));
        }
        return list;
    }

    /**
     * 删除指定id的客户
     */
    @Override
    public void delete(String id) {
        if (usermap.get(id) == null) {
            System.out.println("没有当前id的客户");
        } else {
            System.out.println(usermap.get(id) + "已删除！！！");
            usermap.remove(id);
        }

    }

    /**
     * 修改密码（当前登录用户的）
     */
    public void changepwd(String id) {
        User user = findById(id);
        System.out.println("请输入新密码：");
        String str = sc.next();
        User t = new User(user.getuID(), user.getUname(), user.getUsex(), str, user.getUadress(), user.getUtel(),
                user.getUtime());
        usermap.put(id, t);

    }

    /**
     * 通过id查找对应客户
     */
    @Override
    public User findById(String id) {
        if (usermap.get(id) == null) {
            return null;
        } else {
            return usermap.get(id);
        }

    }

}

4.Dishes属性管理类

package com.softeem.lesson23.test2;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

public class DishesSys implements DAO<Dishes> {
    // 建立一个菜品的map集合，其中菜品的id为map的键，整个菜品对象为map的值
    static Map<String, Dishes> dishesmap = new HashMap<>();
    Set<String> keys = dishesmap.keySet();

    /**
     * 添加菜品
     */
    @Override
    public void insert(Dishes t) {
        dishesmap.put(t.getdID(), t);

    }

    /**
     * 通过id来寻找菜品
     */

    @Override
    public Dishes findById(String id) {
        if (dishesmap.get(id) == null) {
            return null;
        } else {
            return dishesmap.get(id);
        }
    }

    /**
     * 根据菜品类型查找菜品
     */
    public List<Dishes> findByType(String type) {
        List<Dishes> list = new ArrayList<>();
        for (String key : keys) {
            if (Objects.equals(type, dishesmap.get(key).getDtype())) {
                list.add(dishesmap.get(key));
            }

        }
        return list;
    }

    /**
     * 查询所有菜品
     */
    @Override
    public List<Dishes> findAll() {
        List<Dishes> list = new ArrayList<>();

        for (String str : keys) {
            list.add(dishesmap.get(str));
        }
        return list;
    }

    public void selectBytype(String typename) {
        int count = 0;
        for (String key : keys) {
            if (Objects.equals(dishesmap.get(key).getDtype(), typename)) {
                System.out.println(dishesmap.get(key));
                count++;
            }
        }
        if (count == 0) {
            System.out.println("没有当前类别的菜品！");
        }
    }

    /**
     * 删除指定id菜品
     */
    @Override
    public void delete(String id) {
        if (dishesmap.get(id) == null) {
            System.out.println("输入id错误...");
        } else {
            dishesmap.remove(id);
        }

    }
}

以上基本就是代码的核心部分，剩下的部分就简化很多了，建立一个菜单类，分别对其进行不同调用就行了
三、菜单类

package com.softeem.lesson23.test2;

import java.util.Objects;
import java.util.Scanner;

public class Menu {
    static AdminSys admin = new AdminSys();
    Scanner sc = new Scanner(System.in);

    public void showMenu() {
        admin.addMessage();

        System.out.println("请输入账号和密码：按照(账号/密码)");
        String str = sc.next();
        String[] info = str.split("/");
        if (info.length < 2) {
            System.out.println("输入有误，请重新输入：");
            showMenu();
        } else {
            if (admin.findById(info[0]) != null && Objects.equals(admin.findById(info[0]).getApwd(), info[1])) {
                adminMenu();
            } else if (admin.findUserByid(info[0]) != null
                    && Objects.equals(info[1], admin.findUserByid(info[0]).getUpwd())) {
                User user = admin.findUserByid(info[0]);
                userMenu(user);
            } else {
                System.out.println("输入有误，请重新输入....");
                showMenu();
            }
        }

    }

    public void userMenu(User user) {
        System.out.println("=========欢迎来到订餐系统=======");
        System.out.println("====【1】点餐=================");
        System.out.println("====【2】根据菜品类别显示所有菜品===");
        System.out.println("====【3】查看所有订单============");
        System.out.println("====【4】修改密码===============");
        System.out.println("====【5】个人信息显示============");
        System.out.println("====【6】退出==================");
        System.out.println("请输入您要进行的操作：");
        String n = sc.next();
        switch (n) {
        case "1":
            admin.shopDishes(user);
            userMenu(user);
            break;
        case "2":
            admin.ShowOfTypeByUser();
            userMenu(user);
            break;
        case "3":
            admin.showAllOrderByUser(user);
            userMenu(user);
            break;
        case "4":
            admin.changePwdByUser(user);
            userMenu(user);
            break;
        case "5":
            admin.showByUser(user);
            userMenu(user);
            break;
        case "6":
            System.out.println("谢谢使用，再见！");
            System.exit(0);
        default:
            System.out.println("输入错误，请重新输入：");
            userMenu(user);
        }
    }

    public void adminMenu() {
        System.out.println("=========欢迎您尊贵的管理员=======");
        System.out.println("====【1】添加菜品===============");
        System.out.println("====【2】查看所有菜品信息显示=======");
        System.out.println("====【3】查看指定类别的菜品信息=====");
        System.out.println("====【4】根据菜品id修改菜品价格=====");
        System.out.println("====【5】删除指定id的菜品=========");
        System.out.println("====【6】添加客户================");
        System.out.println("====【7】查看客户列表=============");
        System.out.println("====【8】删除指定id的用户==========");
        System.out.println("====【9】订单列表显示=============");
        System.out.println("====【10】根据订单id修改订单状态====");
        System.out.println("====【11】退出=================");
        String m = sc.next();
        switch (m) {
        case "1":
            admin.addDishes();
            adminMenu();
            break;
        case "2":
            System.out.println("请输入您需要每行显示多少数据：");
            int pageSize = sc.nextInt();
            admin.showAllDishes(pageSize);
            adminMenu();
            break;
        case "3":
            admin.selecBytypeOfAdmin();
            adminMenu();
            break;
        case "4":
            admin.selectByDishesID();
            adminMenu();
            break;
        case "5":
            admin.deleteDishes();
            adminMenu();
            break;
        case "6":
            admin.addUser();
            adminMenu();
            break;
        case "7":
            admin.findUser();
            adminMenu();
            break;
        case "8":
            admin.deleteUserByAdmin();
            adminMenu();
            break;
        case "9":
            admin.showAllOrder();
            adminMenu();
            break;
        case "10":
            admin.changeOrderValue();
            adminMenu();
            break;
        case "11":
            System.out.println("谢谢使用，再见！");
            System.exit(0);
            break;
        default:
            System.out.println("输入错误，请重新输入：");
            adminMenu();
        }
    }
}

这里switch采取String（jdk1.7以后才支持）可以让用户就算输入错误也不会报错导致程序运行终止，又要重新输入（我摊牌了，就是懒）。
四、测试类

package com.softeem.lesson23.test2;

public class Test {
    public static void main(String[] args) {
        Menu m = new Menu();
        m.showMenu();
    }
}

五、实现部分界面截图
在这里插入图片描述