知识文档站

Appearance

点餐

思路分析 ​

多一个模块，同理，根据分层设计，编写相关的类，逐层调用 ​

（1）domain 类（javabean） ​

（2）dao ​

（3）service 层 ​

（4）view：用户界面层 ​

点餐逻辑 ​

（1）生成账单 ​

（2）更新餐桌状态（数据库操作） ​

创建菜单表 ​

sql
#账单流水, 考虑可以分开结账, 并考虑将来分别统计各个不同菜品的销售情况
create table bill (
	id int primary key auto_increment, #自增主键
	billId varchar(50) not null default '',#账单号可以按照自己规则生成 UUID
	menuId int not null default 0,#菜品的编号, 也可以使用外键
	nums SMALLINT not null default 0,#份数
	money double not null default 0, #金额
	diningTableId int not null default 0, #餐桌
	billDate datetime not null ,#订单日期
	state varchar(50) not null default '' # 状态 '未结账' , '已经结账', '挂单'
)charset=utf8;

Bill ​

java
package domain;

import java.util.Date;

/**
 * ClassName: Bill
 * Package: domain
 * Description:
 *
 * @author jacksonling
 * @version 1.0
 * @Date 2025-08-07 19:54
 */
public class Bill {
    private Integer id;
    private String billId;
    private Integer menuId;
    private Integer nums;
    private Double money;
    private Integer diningTableId;
    private Date billDate;
    private String state;

    public Bill() {
    }

    public Bill(Integer id, String billId, Integer menuId, Integer nums, Double money, Integer diningTableId, Date billDate, String state) {
        this.id = id;
        this.billId = billId;
        this.menuId = menuId;
        this.nums = nums;
        this.money = money;
        this.diningTableId = diningTableId;
        this.billDate = billDate;
        this.state = state;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getBillId() {
        return billId;
    }

    public void setBillId(String billId) {
        this.billId = billId;
    }

    public Integer getMenuId() {
        return menuId;
    }

    public void setMenuId(Integer menuId) {
        this.menuId = menuId;
    }

    public Integer getNums() {
        return nums;
    }

    public void setNums(Integer nums) {
        this.nums = nums;
    }

    public Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }

    public Integer getDiningTableId() {
        return diningTableId;
    }

    public void setDiningTableId(Integer diningTableId) {
        this.diningTableId = diningTableId;
    }

    public Date getBillDate() {
        return billDate;
    }

    public void setBillDate(Date billDate) {
        this.billDate = billDate;
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    @Override
    public String toString() {
        return  id +
                "\t\t" + menuId +
                "\t\t\t" + nums +
                "\t\t\t" + money +
                "\t\t" + diningTableId +
                "\t\t\t" + billDate +
                "\t\t\t" + state ;
    }
}

BillDao ​

java
package dao;

/**
 * ClassName: BillDao
 * Package: dao
 * Description:
 *
 * @author jacksonling
 * @version 1.0
 * @Date 2025-08-07 19:55
 */
public class BillDao extends BasicDao<Bill>{

}

更新 MenuService ​

提供 getMenuById( ) 方法，根据菜品 id 返回一个菜品对象，供 BillService 调用，结合点餐份数，计算点餐产生的账单金额，保存到数据库中 ​

java
package service;

import dao.MenuDao;
import domain.Menu;

import java.util.List;

/**
 * ClassName: MenuService
 * Package: service
 * Description:
 *
 * @author jacksonling
 * @version 1.0
 * @Date 2025-08-06 18:35
 */
public class MenuService {

    //定义MenuDAO 属性
    private MenuDao menuDao = new MenuDao();

    //返回所有的菜品，在界面层调用
    public void listMenu(){
        List<Menu> menus = menuDao.queryTable("select * from menu", Menu.class);
        System.out.println("\n菜品编号\t\t菜品名\t\t类别\t\t价格");
        for (Menu menu : menus) {
            System.out.println(menu);
        }
        System.out.println("==============显示完毕============");
    }

    // 被 BillService 调用，用于返回菜品对象，计算价格
    public Menu getMenuById(int id) {
        return menuDao.queryLine("select * from menu where id = ?", Menu.class, id);
    }
}

更新 DiningTableService ​

提供 updateDiningTableState( ) 方法，在点完餐后及时更新餐桌状态为 " 就餐中 " ​

java
package service;

import dao.DiningTableDao;
import domain.DiningTable;
import utils.Utility;

import java.util.List;

/**
 * ClassName: DiningTableService
 * Package: service
 * Description:
 *
 * @author jacksonling
 * @version 1.0
 * @Date 2025-08-06 16:21
 */
public class DiningTableService {
    // 创建 Dao 对象
    private DiningTableDao diningTableDao = new DiningTableDao();

    // 编写方法，返回所有餐桌状态并显示
    public void listDiningTale(){
        List<DiningTable> diningTables = diningTableDao.queryTable("select id, state from diningTable", DiningTable.class);
        System.out.println("\n餐桌编号\t\t餐桌状态");
        for (DiningTable diningTable : diningTables) {
            System.out.println(diningTable);
        }
        System.out.println("==============显示完毕============");
    }

    /*
         餐桌预定的前提条件
        （1）预定的餐桌编号存在
        （2）餐桌状态为空
     */
    // 接收用户输入，根据 id 返回 DiningTable 对象，在界面层判断是否为空进而判断餐桌是否存在
    public DiningTable getDiningTableById(int id){
        return diningTableDao.queryLine("select * from diningTable where id = ?", DiningTable.class, id);
    }

    // 如果餐桌可以预定，接收预定信息，更新餐桌状态，返回 boolean，用于判断是否预定成功
    public boolean orderDiningTable(int id, String orderName, String orderTel) {
        // 返回影响的行数
        int update = diningTableDao.update("update diningTable set state='已经预定', orderName=?, orderTel=? where id=?", orderName, orderTel, id);
        return  update > 0;
    }

    // 餐桌预定功能
    public void orderDiningTable(){
        System.out.println("==============预定餐桌============");
        System.out.print("请选择要预定的餐桌编号(-1退出): ");
        int orderId = Utility.readInt();
        if (orderId == -1) {
            System.out.println("==============取消预订餐桌============");
            return;
        }
        //该方法得到的是 Y 或者 N
        char key = Utility.readConfirmSelection();
        if (key == 'Y') {//要预定

            // 判断预定的餐桌是否存在
            DiningTable diningTable = getDiningTableById(orderId);
            if (diningTable == null) {
                System.out.println("==============预订餐桌不存在============");
                return;
            }
            // 判断餐桌的状态是否 "空"
            if (!("空".equals(diningTable.getState()))) {//说明当前这个餐桌不是 "空" 状态
                System.out.println("==============该餐桌已经预定或者就餐中============");
                return;
            }

            //接收预定信息
            System.out.print("预定人的名字: ");
            String orderName = Utility.readString(50);
            System.out.print("预定人的电话: ");
            String orderTel = Utility.readString(50);

            //更新餐桌状态
            if (orderDiningTable(orderId, orderName, orderTel)) {
                System.out.println("==============预订餐桌成功============");
            } else {
                System.out.println("==============预订餐桌失败============");
            }

        } else {
            System.out.println("==============取消预订餐桌============");
        }
    }

    // 在点餐完成后，需要更新餐桌状态
    public boolean updateDiningTableState(int id, String state) {

        int update = diningTableDao.update("update diningTable set state=? where id=?", state, id);
        return update > 0;
    }
}

BillService ​

java
package service;

import dao.BillDao;
import domain.DiningTable;
import domain.Menu;
import utils.Utility;

import java.util.UUID;

/**
 * ClassName: BillService
 * Package: service
 * Description:
 *
 * @author jacksonling
 * @version 1.0
 * @Date 2025-08-07 19:56
 */
public class BillService {
    private BillDao billDao = new BillDao();

    // 调用 MenuService 类中的方法，传入 id，返回菜品对象，用于计算价格
    private MenuService menuService = new MenuService();

    // 点完餐后需要更新餐桌状态
    DiningTableService diningTableService = new DiningTableService();

    /**
     * 点餐功能
     * （1）生成账单
     * 参数：订单号、菜品编号、份数、金额、餐桌号、订单日期、订单状态（未结账、已经结账、挂单...）
     * 传入参数：菜品编号、份数、餐桌号（）
     * （2）更新餐桌状态（数据库）
     */
    public boolean orderMenu(int menuId, int nums, int diningTableId) {
        // 随机生成一个订单号
        String billId = UUID.randomUUID().toString();

        // 更新账单表，同时根据传入信息计算余额
        int update = billDao.update("insert into bill values(null,?,?,?,?,?,now(),'未结账')",
                billId, menuId, nums, menuService.getMenuById(menuId).getPrice() * nums, diningTableId);

        if (update <= 0) {
            return false;
        }

        //需要更新对应餐桌的状态
        return diningTableService.updateDiningTableState(diningTableId, "就餐中");

    }

    // 用户层点餐界面
    public void orderMenu() {
        System.out.println("==============点餐服务============");
        System.out.print("请输入点餐的桌号(-1退出): ");
        int orderDiningTableId = Utility.readInt();
        if (orderDiningTableId == -1) {
            System.out.println("==============取消点餐============");
            return;
        }
        System.out.print("请输入点餐的菜品号(-1退出): ");
        int orderMenuId = Utility.readInt();
        if (orderMenuId == -1) {
            System.out.println("==============取消点餐============");
            return;
        }
        System.out.print("请输入点餐的菜品量(-1退出): ");
        int orderNums = Utility.readInt();
        if (orderNums == -1) {
            System.out.println("==============取消点餐============");
            return;
        }

        //验证餐桌号是否存在
        DiningTable diningTable = diningTableService.getDiningTableById(orderDiningTableId);
        if (diningTable == null) {
            System.out.println("==============餐桌号不存在============");
            return;
        }
        //验证菜品编号
        Menu menu = menuService.getMenuById(orderMenuId);
        if (menu == null) {
            System.out.println("==============菜品号不存在============");
            return;
        }

        //点餐
        if (orderMenu(orderMenuId, orderNums, orderDiningTableId)) {
            System.out.println("==============点餐成功============");
        } else {
            System.out.println("==============点餐失败============");
        }

    }


}

View ​

java
package view;

import com.sun.org.apache.bcel.internal.generic.NEW;
import domain.Employee;
import service.BillService;
import service.DiningTableService;
import service.EmployeeService;
import service.MenuService;
import utils.Utility;

/**
 * ClassName: logInView
 * Package: view
 * Description:
 *
 * @author jacksonling
 * @version 1.0
 * @Date 2025-08-06 14:09
 */

public class View {
    // 循环结束标志
    boolean loop = true;
    // 接收用户输入
    String key = "";

    // 创建 EmployeeService 对象
    EmployeeService employeeService = new EmployeeService();
    // 创建 DiningTableService 对象
    DiningTableService diningTableService = new DiningTableService();
    // 创建 MenuService 对象
    MenuService menuService = new MenuService();
    // 创建 BillService 对象
    BillService billService = new BillService();

    //显示主菜单
    public void mainMenu() {
        while (loop) {
            System.out.println("\n===============满汉楼================");
            System.out.println("\t\t 1 登录满汉楼");
            System.out.println("\t\t 2 退出满汉楼");
            System.out.print("请输入你的选择: ");
            key = Utility.readString(1);
            switch (key) {
                case "1":
                    System.out.print("输入员工号: ");
                    String empId = Utility.readString(50);
                    System.out.print("输入密  码: ");
                    String pwd = Utility.readString(50);
                    Employee employee = employeeService.getEmployeeByIdAndPwd(empId, pwd);
                    if (employee != null) { //说明存在该用户
                        System.out.println("===============登录成功[" + employee.getName() + "]================\n");
                        //显示二级菜单, 这里二级菜单是循环操作，所以做成while
                        while (loop) {
                            System.out.println("\n===============满汉楼(二级菜单)================");
                            System.out.println("\t\t 1 显示餐桌状态");
                            System.out.println("\t\t 2 预定餐桌");
                            System.out.println("\t\t 3 显示所有菜品");
                            System.out.println("\t\t 4 点餐服务");
                            System.out.println("\t\t 5 查看账单");
                            System.out.println("\t\t 6 结账");
                            System.out.println("\t\t 9 退出满汉楼");
                            System.out.print("请输入你的选择: ");
                            key = Utility.readString(1);
                            switch (key) {
                                case "1":
                                    // 显示餐桌状态
                                    diningTableService.listDiningTale();
                                    break;
                                case "2":
                                    // 预定餐桌
                                    diningTableService.orderDiningTable();
                                    break;
                                case "3":
                                    // 显示所有菜品
                                    menuService.listMenu();
                                    break;
                                case "4":
                                    // 点餐服务
                                    billService.orderMenu();
                                    break;
                                case "5":
                                    // 查看账单
                                    System.out.println("查看账单");
                                    break;
                                case "6":
                                    // 结账
                                    System.out.println("结账");
                                    break;
                                case "9":
                                    loop = false;
                                    break;
                                default:
                                    System.out.println("你的输入有误，请重新输入");
                                    break;
                            }
                        }
                    } else {
                        System.out.println("=====登录失败（用户名 / 密码错误）=====");
                    }
                    break;
                case "2":
                    loop = false;//
                    break;
                default:
                    System.out.println("你输入有误，请重新输入.");
            }
        }
        System.out.println("退出了满汉楼系统~");
    }
}

Copyright © 2025 Jackson 凌 All Rights Reserved. | 粤ICP备2025441629号-1