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程序框架图
代码实现
数据库
-- 创建满汉楼的数据库
CREATE DATABASE mhl
-- 创建表 employee 表 (主键id, empId, name, pwd, job, 如果需要可以自己加字段等)
#用户表
CREATE TABLE employee (
id INT PRIMARY KEY AUTO_INCREMENT, #自增
empId VARCHAR(50) UNIQUE NOT NULL DEFAULT '',#员工号
pwd CHAR(32) NOT NULL DEFAULT '',#密码md5
NAME VARCHAR(50) NOT NULL DEFAULT '',#姓名
job VARCHAR(50) NOT NULL DEFAULT '' #岗位
)CHARSET=utf8;
DROP TABLE employee
#添加测试数据
INSERT INTO employee VALUES(NULL, '6668612', MD5('123456'), '张三丰', '经理');
INSERT INTO employee VALUES(NULL, '6668622', MD5('123456'),'小龙女', '服务员');
INSERT INTO employee VALUES(NULL, '6668633', MD5('123456'), '张无忌', '收银员');
INSERT INTO employee VALUES(NULL, '666666', MD5('123456'), '老韩', '经理');
SELECT * FROM employee;
SELECT * FROM employee WHERE empId='666666' AND pwd=MD5('123456')
-- 创建diningTable 表(id, state , orderName, orderTel ....)
CREATE TABLE diningTable (
id INT PRIMARY KEY AUTO_INCREMENT, #自增, 表示餐桌编号
state VARCHAR(20) NOT NULL DEFAULT '',#餐桌的状态
orderName VARCHAR(50) NOT NULL DEFAULT '',#预订人的名字
orderTel VARCHAR(20) NOT NULL DEFAULT ''
)CHARSET=utf8;
#测试数据
INSERT INTO diningTable VALUES(NULL, '空','','');
INSERT INTO diningTable VALUES(NULL, '空','','');
INSERT INTO diningTable VALUES(NULL, '空','','');
SELECT * FROM diningTable
SELECT * FROM diningTable
SELECT * FROM diningTable WHERE id = 1
UPDATE diningTable SET state='空', orderName='', orderTel='' WHERE id=1
-- 创建menu表(id, name, type, price)
#菜谱
CREATE TABLE menu (
id INT PRIMARY KEY AUTO_INCREMENT, #自增主键，作为菜谱编号(唯一)
NAME VARCHAR(50) NOT NULL DEFAULT '',#菜品名称
TYPE VARCHAR(50) NOT NULL DEFAULT '', #菜品种类
price DOUBLE NOT NULL DEFAULT 0#价格
)CHARSET=utf8;
#测试数据
INSERT INTO menu VALUES(NULL, '八宝饭', '主食', 10);
INSERT INTO menu VALUES(NULL, '叉烧包', '主食', 20);
INSERT INTO menu VALUES(NULL, '宫保鸡丁', '热菜', 30);
INSERT INTO menu VALUES(NULL, '山药拨鱼', '凉菜', 14);
INSERT INTO menu VALUES(NULL, '银丝卷', '甜食', 9);
INSERT INTO menu VALUES(NULL, '水煮鱼', '热菜', 26);
INSERT INTO menu VALUES(NULL, '甲鱼汤', '汤类', 100);
INSERT INTO menu VALUES(NULL, '鸡蛋汤', '汤类', 16);
SELECT * FROM menu;
#同学们可以单独创建一张表，表示菜品的类别
#增加表 bill 账单表(id, billId, menuId, nums, billDate, money, state, diningTableId )
#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 INT 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','现金','支付宝','坏账'
)CHARSET=utf8;
SELECT * FROM bill;
select * from bill
SELECT * FROM menu WHERE id = 1
UPDATE diningTable SET state=? WHERE id=?
SELECT * FROM diningTable
-- 查出某个餐桌是否有未结账的账单
select * from bill where diningTableId=1 and state = '未结账' limit 0, 1Java
`-- src
|-- com
| `-- hspedu
| `-- mhl
| |-- dao
| | |-- BasicDAO.java
| | |-- BillDAO.java
| | |-- DiningTableDAO.java
| | |-- EmployeeDAO.java
| | |-- MenuDAO.java
| | `-- MultiTableDAO.java
| |-- domain
| | |-- Bill.java
| | |-- DiningTable.java
| | |-- Employee.java
| | |-- Menu.java
| | `-- MultiTableBean.java
| |-- service
| | |-- BillService.java
| | |-- DiningTableService.java
| | |-- EmployeeService.java
| | `-- MenuService.java
| |-- utils
| | |-- JDBCUtilsByDruid.java
| | `-- Utility.java
| `-- view
| `-- MHLView.java
`-- druid.propertiessrc/com/hspedu/mhl/dao/BasicDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.utils.JDBCUtilsByDruid;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
/**
* 开发BasicDAO , 是其他DAO的父类
*/
public class BasicDAO { //泛型指定具体类型
private QueryRunner qr = new QueryRunner();
//开发通用的dml方法, 针对任意的表
public int update(String sql, Object... parameters) {
Connection connection = null;
try {
connection = JDBCUtilsByDruid.getConnection();
int update = qr.update(connection, sql, parameters);
return update;
} catch (SQLException e) {
throw new RuntimeException(e); //将编译异常->运行异常 ,抛出
} finally {
JDBCUtilsByDruid.close(null, null, connection);
}
}
//返回多个对象(即查询的结果是多行), 针对任意表
/**
*
* @param sql sql 语句，可以有 ?
* @param clazz 传入一个类的Class对象 比如 Actor.class
* @param parameters 传入 ? 的具体的值，可以是多个
* @return 根据Actor.class 返回对应的 ArrayList 集合
*/
public List queryMulti(String sql, Class clazz, Object... parameters) {
Connection connection = null;
try {
connection = JDBCUtilsByDruid.getConnection();
return qr.query(connection, sql, new BeanListHandler(clazz), parameters);
} catch (SQLException e) {
throw new RuntimeException(e); //将编译异常->运行异常 ,抛出
} finally {
JDBCUtilsByDruid.close(null, null, connection);
}
}
//查询单行结果 的通用方法
public T querySingle(String sql, Class clazz, Object... parameters) {
Connection connection = null;
try {
connection = JDBCUtilsByDruid.getConnection();
return qr.query(connection, sql, new BeanHandler(clazz), parameters);
} catch (SQLException e) {
throw new RuntimeException(e); //将编译异常->运行异常 ,抛出
} finally {
JDBCUtilsByDruid.close(null, null, connection);
}
}
//查询单行单列的方法,即返回单值的方法
public Object queryScalar(String sql, Object... parameters) {
Connection connection = null;
try {
connection = JDBCUtilsByDruid.getConnection();
return qr.query(connection, sql, new ScalarHandler(), parameters);
} catch (SQLException e) {
throw new RuntimeException(e); //将编译异常->运行异常 ,抛出
} finally {
JDBCUtilsByDruid.close(null, null, connection);
}
}
}src/com/hspedu/mhl/dao/BillDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.Bill;
public class BillDAO extends BasicDAO {
}src/com/hspedu/mhl/dao/DiningTableDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.DiningTable;
public class DiningTableDAO extends BasicDAO {
//如果有特别的操作，可以写在 DiningTableDAO
}src/com/hspedu/mhl/dao/EmployeeDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.Employee;
public class EmployeeDAO extends BasicDAO {
//这里还可以写特有的操作.
}src/com/hspedu/mhl/dao/MenuDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.Menu;
public class MenuDAO extends BasicDAOsrc/com/hspedu/mhl/dao/MultiTableDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.MultiTableBean;
public class MultiTableDAO extends BasicDAO {
}src/com/hspedu/mhl/domain/Bill.java
package com.hspedu.mhl.domain;
import java.util.Date;
/**
* Bill 是javabean 和 bill对应
* 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 int 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'
*/
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 +
"tt" + menuId +
"ttt" + nums +
"ttt" + money +
"t" + diningTableId +
"tt" + billDate +
"tt" + state ;
}
}src/com/hspedu/mhl/domain/DiningTable.java
package com.hspedu.mhl.domain;
/**
* 这是一个javabean 和 diningTable 表对应
* id int primary key auto_increment, #自增, 表示餐桌编号
* state varchar(20) not null default '',#餐桌的状态
* orderName varchar(50) not null default '',#预订人的名字
* orderTel varchar(20) not null default ''
*/
public class DiningTable {
private Integer id;
private String state;
private String orderName;
private String orderTel;
public DiningTable() {
}
public DiningTable(Integer id, String state, String orderName, String orderTel) {
this.id = id;
this.state = state;
this.orderName = orderName;
this.orderTel = orderTel;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getOrderName() {
return orderName;
}
public void setOrderName(String orderName) {
this.orderName = orderName;
}
public String getOrderTel() {
return orderTel;
}
public void setOrderTel(String orderTel) {
this.orderTel = orderTel;
}
@Override
public String toString() {
return id + "ttt" + state;
}
}src/com/hspedu/mhl/domain/Employee.java
package com.hspedu.mhl.domain;
/**
* 这是一个javabean 和 employee对应
* id int primary key auto_increment, #自增
* empId varchar(50) not null default '',#员工号
* pwd char(32) not null default '',#密码md5
* name varchar(50) not null default '',#姓名
* job varchar(50) not null default '' #岗位
*/
public class Employee {
private Integer id;
private String empId;
private String pwd;
private String name;
private String job;
public Employee() { //无参构造器，底层apache-dbutils反射需要
}
public Employee(Integer id, String empId, String pwd, String name, String job) {
this.id = id;
this.empId = empId;
this.pwd = pwd;
this.name = name;
this.job = job;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getEmpId() {
return empId;
}
public void setEmpId(String empId) {
this.empId = empId;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getJob() {
return job;
}
public void setJob(String job) {
this.job = job;
}
}src/com/hspedu/mhl/domain/Menu.java
package com.hspedu.mhl.domain;
/**
* 该类(javabean)和 menu 表对应
* id int primary key auto_increment, #自增主键，作为菜谱编号(唯一)
* name varchar(50) not null default '',#菜品名称
* type varchar(50) not null default '', #菜品种类
* price double not null default 0#价格
*/
public class Menu {
private Integer id;
private String name;
private String type;
private Double price;
public Menu() {//无参构造器
}
public Menu(Integer id, String name, String type, Double price) {
this.id = id;
this.name = name;
this.type = type;
this.price = price;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
@Override
public String toString() {
return id + "ttt" + name + "tt" + type + "tt" + price;
}
}src/com/hspedu/mhl/domain/MultiTableBean.java
package com.hspedu.mhl.domain;
import java.util.Date;
/**
* 这是一个javabean 可以和多张表进行对应
*/
public class MultiTableBean {
private Integer id;
private String billId;
private Integer menuId;
private Integer nums;
private Double money;
private Integer diningTableId;
private Date billDate;
private String state;
//增加一个来自menu表的列 name
//思考 这里的属性名是否一定要和表的列名保持一致.
//答: 可以不一致，但是需要sql做相应的修改, 规范需要保持一致（例如 SELECT Name AS name2 他会调用对应的setName2构造方法）.
private String name;
//增加来自menu表的列 price
private Double price;//默认值 nulll
// 实际上是调用无参构造器，进行反射调用，然后通过setter和getter方法进行调用的：
public MultiTableBean() {
System.out.println("反射调用....");
}
// public MultiTableBean(Integer id, String billId, Integer menuId, Integer nums, Double money, Integer diningTableId, Date billDate, String state, String name, Double price) {
// this.id = id;
// this.billId = billId;
// this.menuId = menuId;
// this.nums = nums;
// this.money = money;
// this.diningTableId = diningTableId;
// this.billDate = billDate;
// this.state = state;
// this.name = name;
// this.price = price;
// }
//给price生成setter 和 getter
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
//给name生成setter 和 getter
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
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 +
"tt" + menuId +
"ttt" + nums +
"ttt" + money +
"t" + diningTableId +
"tt" + billDate +
"tt" + state +
"tt" + name +
"tt" + price;
}
}src/com/hspedu/mhl/service/BillService.java
package com.hspedu.mhl.service;
import com.hspedu.mhl.dao.BillDAO;
import com.hspedu.mhl.dao.MultiTableDAO;
import com.hspedu.mhl.domain.Bill;
import com.hspedu.mhl.domain.MultiTableBean;
import java.util.List;
import java.util.UUID;
/**
* 处理和账单相关的业务逻辑
*/
public class BillService {
//定义BillDAO属性
private BillDAO billDAO = new BillDAO();
//定义MenuService 属性
private MenuService menuService = new MenuService();
//定义DiningTableService属性
private DiningTableService diningTableService = new DiningTableService();
private MultiTableDAO multiTableDAO = new MultiTableDAO();
//思考
//编写点餐的方法
//1. 生成账单
//2. 需要更新对应餐桌的状态
//3. 如果成功返回true, 否则返回false
public boolean orderMenu(int menuId, int nums, int diningTableId) {
//生成一个账单号,UUID
String billID = UUID.randomUUID().toString();
//将账单生成到bill表, 要求直接计算账单金额
int update = billDAO.update("insert into bill values(null,?,?,?,?,?,now(),'未结账')",
billID, menuId, nums, menuService.getMenuById(menuId).getPrice() * nums, diningTableId);
if (update list() {
return billDAO.queryMulti("select * from bill", Bill.class);
}
//返回所有的账单并带有菜品名,价格， 提供给View调用
public List list2() {
return multiTableDAO.queryMulti("SELECT bill.*, NAME " +
"FROM bill, menu " +
"WHERE bill.menuId = menu.id", MultiTableBean.class);
}
//查看某个餐桌是否有未结账的账单
public boolean hasPayBillByDiningTableId(int diningTableId) {
Bill bill =
billDAO.querySingle("SELECT * FROM bill WHERE diningTableId=? AND state = '未结账' LIMIT 0, 1", Bill.class, diningTableId);
return bill != null;
}
//完成结账[如果餐桌存在，并且该餐桌有未结账的账单]
//如果成功，返回true, 失败返回 false
public boolean payBill(int diningTableId, String payMode) {
//如果这里使用事务的话，需要用ThreadLocal来解决 , 框架中比如mybatis 提供了事务支持
//1. 修改bill表
int update = billDAO.update("update bill set state=? where diningTableId=? and state='未结账'", payMode, diningTableId);
if(update src/com/hspedu/mhl/service/DiningTableService.java
package com.hspedu.mhl.service;
import com.hspedu.mhl.dao.DiningTableDAO;
import com.hspedu.mhl.domain.DiningTable;
import java.util.List;
public class DiningTableService { //业务层
//定义一个DiningTableDAO对象
private DiningTableDAO diningTableDAO = new DiningTableDAO();
//返回所有餐桌的信息
public List list() {
return diningTableDAO.queryMulti("select id, state from diningTable", DiningTable.class);
}
//根据id , 查询对应的餐桌DiningTable 对象
//,如果返回null , 表示id编号对应的餐桌不存在
public DiningTable getDiningTableById(int id) {
//小技巧：把sql语句放在查询分析器去测试一下.
return diningTableDAO.querySingle("select * from diningTable where id = ?", DiningTable.class, id);
}
//如果餐桌可以预定，调用方法，对其状态进行更新(包括预定人的名字和电话)
public boolean orderDiningTable(int id, String orderName, String orderTel) {
int update =
diningTableDAO.update("update diningTable set state='已经预定', orderName=?, orderTel=? where id=?", orderName, orderTel, id);
return update > 0;
}
//需要提供一个更新 餐桌状态的方法
public boolean updateDiningTableState(int id, String state) {
int update = diningTableDAO.update("update diningTable set state=? where id=?", state, id);
return update > 0;
}
//提供方法，将指定的餐桌设置为空闲状态
public boolean updateDiningTableToFree(int id, String state) {
int update = diningTableDAO.update("update diningTable set state=?,orderName='',orderTel='' where id=?", state, id);
return update > 0;
}
}src/com/hspedu/mhl/service/EmployeeService.java
package com.hspedu.mhl.service;
import com.hspedu.mhl.dao.EmployeeDAO;
import com.hspedu.mhl.domain.Employee;
/**
* 该类完成对employee表的各种操作(通过调用EmployeeDAO对象完成)
*/
public class EmployeeService {
//定义一个 EmployeeDAO 属性
private EmployeeDAO employeeDAO = new EmployeeDAO();
//方法，根据empId 和 pwd 返回一个Employee对象
//如果查询不到，就返回null
public Employee getEmployeeByIdAndPwd(String empId, String pwd) {
return employeeDAO.querySingle("select * from employee where empId=? and pwd=md5(?)", Employee.class, empId, pwd);
}
}src/com/hspedu/mhl/service/MenuService.java
package com.hspedu.mhl.service;
import com.hspedu.mhl.dao.MenuDAO;
import com.hspedu.mhl.domain.Menu;
import java.util.List;
/**
* 完成对menu表的各种操作(通过调用MenuDAO)
*/
public class MenuService {
//定义MenuDAO 属性
private MenuDAO menuDAO = new MenuDAO();
//返回所有的菜品, 返回给界面使用
public Listsrc/com/hspedu/mhl/utils/JDBCUtilsByDruid.java
package com.hspedu.mhl.utils;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/**
* 基于druid数据库连接池的工具类
*/
public class JDBCUtilsByDruid {
private static DataSource ds;
//在静态代码块完成 ds初始化
static {
Properties properties = new Properties();
try {
properties.load(new FileInputStream("src\druid.properties"));
ds = DruidDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
}
//编写getConnection方法
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
//关闭连接, 老师再次强调： 在数据库连接池技术中，close 不是真的断掉连接
//而是把使用的Connection对象放回连接池
public static void close(ResultSet resultSet, Statement statement, Connection connection) {
try {
if (resultSet != null) {
resultSet.close();
}
if (statement != null) {
statement.close();
}
if (connection != null) {
connection.close();
}
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}src/com/hspedu/mhl/utils/Utility.java
package com.hspedu.mhl.utils;
/**
工具类的作用:
处理各种情况的用户输入，并且能够按照程序员的需求，得到用户的控制台输入。
*/
import java.util.*;
/**
*/
public class Utility {
//静态属性。。。
private static Scanner scanner = new Scanner(System.in);
/**
* 功能：读取键盘输入的一个菜单选项，值：1——5的范围
* @return 1——5
*/
public static char readMenuSelection() {
char c;
for (; ; ) {
String str = readKeyBoard(1, false);//包含一个字符的字符串
c = str.charAt(0);//将字符串转换成字符char类型
if (c != '1' && c != '2' &&
c != '3' && c != '4' && c != '5') {
System.out.print("选择错误，请重新输入：");
} else break;
}
return c;
}
/**
* 功能：读取键盘输入的一个字符
* @return 一个字符
*/
public static char readChar() {
String str = readKeyBoard(1, false);//就是一个字符
return str.charAt(0);
}
/**
* 功能：读取键盘输入的一个字符，如果直接按回车，则返回指定的默认值；否则返回输入的那个字符
* @param defaultValue 指定的默认值
* @return 默认值或输入的字符
*/
public static char readChar(char defaultValue) {
String str = readKeyBoard(1, true);//要么是空字符串，要么是一个字符
return (str.length() == 0) ? defaultValue : str.charAt(0);
}
/**
* 功能：读取键盘输入的整型，长度小于2位
* @return 整数
*/
public static int readInt() {
int n;
for (; ; ) {
String str = readKeyBoard(2, false);//一个整数，长度 Y n=>N
String str = readKeyBoard(1, false).toUpperCase();
c = str.charAt(0);
if (c == 'Y' || c == 'N') {
break;
} else {
System.out.print("选择错误，请重新输入：");
}
}
return c;
}
/**
* 功能： 读取一个字符串
* @param limit 读取的长度
* @param blankReturn 如果为true ,表示 可以读空字符串。
* 如果为false表示 不能读空字符串。
*
* 如果输入为空，或者输入大于limit的长度，就会提示重新输入。
* @return
*/
private static String readKeyBoard(int limit, boolean blankReturn) {
//定义了字符串
String line = "";
//scanner.hasNextLine() 判断有没有下一行
while (scanner.hasNextLine()) {
line = scanner.nextLine();//读取这一行
//如果line.length=0, 即用户没有输入任何内容，直接回车
if (line.length() == 0) {
if (blankReturn) return line;//如果blankReturn=true,可以返回空串
else continue; //如果blankReturn=false,不接受空串，必须输入内容
}
//如果用户输入的内容大于了 limit，就提示重写输入
//如果用户如的内容 >0 limit) {
System.out.print("输入长度（不能大于" + limit + "）错误，请重新输入：");
continue;
}
break;
}
return line;
}
}src/com/hspedu/mhl/view/MHLView.java
package com.hspedu.mhl.view;
import com.hspedu.mhl.domain.*;
import com.hspedu.mhl.service.BillService;
import com.hspedu.mhl.service.DiningTableService;
import com.hspedu.mhl.service.EmployeeService;
import com.hspedu.mhl.service.MenuService;
import com.hspedu.mhl.utils.Utility;
import java.util.List;
import java.util.UUID;
/**
* 这是主界面
*/
public class MHLView {
//控制是否退出菜单
private boolean loop = true;
private String key = ""; //接收用户的选择
//定义EmployeeService 属性
private EmployeeService employeeService = new EmployeeService();
//定义DiningTableService的属性
private DiningTableService diningTableService = new DiningTableService();
//定义MenuService属性
private MenuService menuService = new MenuService();
//定义BillService属性
private BillService billService = new BillService();
public static void main(String[] args) {
new MHLView().mainMenu();
}
//完成结账
public void payBill() {
System.out.println("==============结账服务============");
System.out.print("请选择要结账的餐桌编号(-1退出): ");
int diningTableId = Utility.readInt();
if (diningTableId == -1) {
System.out.println("=============取消结账============");
return;
}
//验证餐桌是否存在
DiningTable diningTable = diningTableService.getDiningTableById(diningTableId);
if (diningTable == null) {
System.out.println("=============结账的餐桌不存在============");
return;
}
//验证餐桌是否有需要结账的账单
if (!billService.hasPayBillByDiningTableId(diningTableId)) {
System.out.println("=============该餐位没有未结账账单============");
return;
}
System.out.print("结账方式(现金/支付宝/微信)回车表示退出: ");
String payMode = Utility.readString(20, "");//说明如果回车，就是返回 ""
if ("".equals(payMode)) {
System.out.println("=============取消结账============");
return;
}
char key = Utility.readConfirmSelection();
if (key == 'Y') { //结账
//调用我们写的方法
if (billService.payBill(diningTableId, payMode)) {
System.out.println("=============完成结账============");
} else {
System.out.println("=============结账失败============");
}
} else {
System.out.println("=============取消结账============");
}
}
//显示账单信息
public void listBill() {
// List bills = billService.list();
// System.out.println("n编号tt菜品号tt菜品量tt金额tt桌号tt日期ttttttt状态");
// for (Bill bill : bills) {
// System.out.println(bill);
// }
// System.out.println("==============显示完毕============");
List multiTableBeans = billService.list2();
System.out.println("n编号tt菜品号tt菜品量tt金额tt桌号tt日期ttttttt状态tt菜品名tt价格");
for (MultiTableBean bill : multiTableBeans) {
System.out.println(bill);
}
System.out.println("==============显示完毕============");
}
//完成点餐
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 (billService.orderMenu(orderMenuId, orderNums, orderDiningTableId)) {
System.out.println("==============点餐成功============");
} else {
System.out.println("==============点餐失败============");
}
}
//显示所有菜品
public void listMenu() {
Listsrc/druid.properties
#key=value
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mhl?rewriteBatchedStatements=true
username=root
password=hsp
#initial connection Size
initialSize=10
#min idle connecton size
minIdle=5
#max active connection size
maxActive=50
#max wait time (5000 mil seconds)
maxWait=5000mhl.iml
多表查询思路
可以用MapListHandler实现：
https://www.pianshen.com/article/48341042440/
也可以另写MultiTabBean类，映射多个表，如上所示。
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