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程序框架图
代码实现
数据库
-- 创立满汉楼的数据库CREATE DATABASE mhl-- 创立表 employee 表 (主键id, empId, name, pwd, job, 如果须要能够本人加字段等)#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 '',#明码md5 NAME VARCHAR(50) NOT NULL DEFAULT '',#姓名 job VARCHAR(50) NOT NULL DEFAULT '' #岗位)CHARSET=utf8; DROP TABLE employee#增加测试数据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')-- 创立diningTable 表(id, state , orderName, orderTel ....)CREATE TABLE diningTable ( id INT PRIMARY KEY AUTO_INCREMENT, #自增, 示意餐桌编号 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 diningTableSELECT * FROM diningTableSELECT * FROM diningTable WHERE id = 1UPDATE diningTable SET state='空', orderName='', orderTel='' WHERE id=1-- 创立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(惟一) NAME VARCHAR(50) NOT NULL DEFAULT '',#菜品名称 TYPE VARCHAR(50) NOT NULL DEFAULT '', #菜品品种 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;#同学们能够独自创立一张表，示意菜品的类别#减少表 bill 账单表(id, billId, menuId, nums, billDate, money, state, diningTableId )#账单流水, 思考能够离开结账, 并思考未来别离统计各个不同菜品的销售状况CREATE TABLE bill ( id INT PRIMARY KEY AUTO_INCREMENT, #自增主键 billId VARCHAR(50) NOT NULL DEFAULT '',#账单号能够依照本人规定生成 UUID menuId INT NOT NULL DEFAULT 0,#菜品的编号, 也能够应用外键 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' , '曾经结账', '挂单','现金','支付宝','坏账')CHARSET=utf8;SELECT * FROM bill;select * from billSELECT * FROM menu WHERE id = 1UPDATE 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 , 是其余DAO的父类 */public class BasicDAO<T> { //泛型指定具体类型 private QueryRunner qr = new QueryRunner(); //开发通用的dml办法, 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); //将编译异样->运行异样 ,抛出 } finally { JDBCUtilsByDruid.close(null, null, connection); } } //返回多个对象(即查问的后果是多行), 针对任意表 /** * * @param sql sql 语句，能够有 ? * @param clazz 传入一个类的Class对象 比方 Actor.class * @param parameters 传入 ? 的具体的值，能够是多个 * @return 依据Actor.class 返回对应的 ArrayList 汇合 */ public List<T> queryMulti(String sql, Class<T> clazz, Object... parameters) { Connection connection = null; try { connection = JDBCUtilsByDruid.getConnection(); return qr.query(connection, sql, new BeanListHandler<T>(clazz), parameters); } catch (SQLException e) { throw new RuntimeException(e); //将编译异样->运行异样 ,抛出 } finally { JDBCUtilsByDruid.close(null, null, connection); } } //查问单行后果 的通用办法 public T querySingle(String sql, Class<T> clazz, Object... parameters) { Connection connection = null; try { connection = JDBCUtilsByDruid.getConnection(); return qr.query(connection, sql, new BeanHandler<T>(clazz), parameters); } catch (SQLException e) { throw new RuntimeException(e); //将编译异样->运行异样 ,抛出 } finally { JDBCUtilsByDruid.close(null, null, connection); } } //查问单行单列的办法,即返回单值的办法 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); //将编译异样->运行异样 ,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<Bill> {}src/com/hspedu/mhl/dao/DiningTableDAO.java
package com.hspedu.mhl.dao;import com.hspedu.mhl.domain.DiningTable;public class DiningTableDAO extends BasicDAO<DiningTable> { //如果有特地的操作，能够写在 DiningTableDAO}src/com/hspedu/mhl/dao/EmployeeDAO.java
package com.hspedu.mhl.dao;import com.hspedu.mhl.domain.Employee;public class EmployeeDAO extends BasicDAO<Employee> { //这里还能够写特有的操作.}src/com/hspedu/mhl/dao/MenuDAO.java
package com.hspedu.mhl.dao;import com.hspedu.mhl.domain.Menu;public class MenuDAO extends BasicDAO<Menu> {}src/com/hspedu/mhl/dao/MultiTableDAO.java
package com.hspedu.mhl.dao;import com.hspedu.mhl.domain.MultiTableBean;public class MultiTableDAO extends BasicDAO<MultiTableBean> {}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 '',#账单号能够依照本人规定生成 UUID * menuId int not null default 0,#菜品的编号, 也能够应用外键 * 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' , '曾经结账', '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 + "\t\t" + menuId + "\t\t\t" + nums + "\t\t\t" + money + "\t" + diningTableId + "\t\t" + billDate + "\t\t" + 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, 示意餐桌编号 * 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 + "\t\t\t" + 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 '',#明码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() { //无参结构器，底层apache-dbutils反射须要 } 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(惟一) * name varchar(50) not null default '',#菜品名称 * type varchar(50) not null default '', #菜品品种 * 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() {//无参结构器 } 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 + "\t\t\t" + name + "\t\t" + type + "\t\t" + price; }}src/com/hspedu/mhl/domain/MultiTableBean.java
package com.hspedu.mhl.domain;import java.util.Date;/** * 这是一个javabean 能够和多张表进行对应 */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; //减少一个来自menu表的列 name //思考 这里的属性名是否肯定要和表的列名保持一致. //答: 能够不统一，然而须要sql做相应的批改, 标准须要保持一致（例如 SELECT Name AS name2 他会调用对应的setName2构造方法）. private String name; //减少来自menu表的列 price private Double price;//默认值 nulll // 实际上是调用无参结构器，进行反射调用，而后通过setter和getter办法进行调用的： 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 + "\t\t" + menuId + "\t\t\t" + nums + "\t\t\t" + money + "\t" + diningTableId + "\t\t" + billDate + "\t\t" + state + "\t\t" + name + "\t\t" + 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;/** * 解决和账单相干的业务逻辑 */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 //编写点餐的办法 //1. 生成账单 //2. 须要更新对应餐桌的状态 //3. 如果胜利返回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, 要求间接计算账单金额 int update = billDAO.update("insert into bill values(null,?,?,?,?,?,now(),'未结账')", billID, menuId, nums, menuService.getMenuById(menuId).getPrice() * nums, diningTableId); if (update <= 0) { return false; } //须要更新对应餐桌的状态 return diningTableService.updateDiningTableState(diningTableId, "就餐中"); } //返回所有的账单， 提供给View调用 public List<Bill> 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<MultiTableBean> 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; } //实现结账[如果餐桌存在，并且该餐桌有未结账的账单] //如果胜利，返回true, 失败返回 false public boolean payBill(int diningTableId, String payMode) { //如果这里应用事务的话，须要用ThreadLocal来解决 , 框架中比方mybatis 提供了事务反对 //1. 批改bill表 int update = billDAO.update("update bill set state=? where diningTableId=? and state='未结账'", payMode, diningTableId); if(update <= 0) { //如果更新没有胜利，则示意失败... return false; } //2. 批改diningTable表 //留神：不要间接在这里操作，而应该调用DiningTableService 办法,实现更新，体现各司其职 if(!diningTableService.updateDiningTableToFree(diningTableId, "空")) { return false; } return true; }}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<DiningTable> list() { return diningTableDAO.queryMulti("select id, state from diningTable", DiningTable.class); } //依据id , 查问对应的餐桌DiningTable 对象 //,如果返回null , 示意id编号对应的餐桌不存在 public DiningTable getDiningTableById(int id) { //小技巧：把sql语句放在查问分析器去测试一下. return diningTableDAO.querySingle("select * from diningTable where id = ?", DiningTable.class, id); } //如果餐桌能够预约，调用办法，对其状态进行更新(包含预约人的名字和电话) public boolean orderDiningTable(int id, String orderName, String orderTel) { int update = diningTableDAO.update("update diningTable set state='曾经预约', orderName=?, orderTel=? where id=?", orderName, orderTel, id); return update > 0; } //须要提供一个更新 餐桌状态的办法 public boolean updateDiningTableState(int id, String state) { int update = diningTableDAO.update("update diningTable set state=? where id=?", state, id); return update > 0; } //提供办法，将指定的餐桌设置为闲暇状态 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;/** * 该类实现对employee表的各种操作(通过调用EmployeeDAO对象实现) */public class EmployeeService { //定义一个 EmployeeDAO 属性 private EmployeeDAO employeeDAO = new EmployeeDAO(); //办法，依据empId 和 pwd 返回一个Employee对象 //如果查问不到，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;/** * 实现对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, 返回给界面应用 public List<Menu> list() { return menuDAO.queryMulti("select * from menu", Menu.class); } //须要办法，依据id, 返回Menu对象 public Menu getMenuById(int id) { return menuDAO.querySingle("select * from menu where id = ?", Menu.class, id); }}src/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; //在动态代码块实现 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办法 public static Connection getConnection() throws SQLException { return ds.getConnection(); } //敞开连贯, 老师再次强调： 在数据库连接池技术中，close 不是真的断掉连贯 //而是把应用的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: 解决各种状况的用户输出，并且可能依照程序员的需要，失去用户的控制台输出。*/import java.util.*;/** */public class Utility { //动态属性。。。 private static Scanner scanner = new Scanner(System.in); /** * 性能：读取键盘输入的一个菜单选项，值：1——5的范畴 * @return 1——5 */ public static char readMenuSelection() { char c; for (; ; ) { String str = readKeyBoard(1, false);//蕴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("抉择谬误，请从新输出："); } else break; } return c; } /** * 性能：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); } /** * 性能：读取键盘输入的一个字符，如果间接按回车，则返回指定的默认值；否则返回输出的那个字符 * @param defaultValue 指定的默认值 * @return 默认值或输出的字符 */ 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); } /** * 性能：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<=2位 try { n = Integer.parseInt(str);//将字符串转换成整数 break; } catch (NumberFormatException e) { System.out.print("数字输出谬误，请从新输出："); } } return n; } /** * 性能：读取键盘输入的 整数或默认值，如果间接回车，则返回默认值，否则返回输出的整数 * @param defaultValue 指定的默认值 * @return 整数或默认值 */ public static int readInt(int defaultValue) { int n; for (; ; ) { String str = readKeyBoard(10, true); if (str.equals("")) { return defaultValue; } //异样解决... try { n = Integer.parseInt(str); break; } catch (NumberFormatException e) { System.out.print("数字输出谬误，请从新输出："); } } return n; } /** * 性能：读取键盘输入的指定长度的字符串 * @param limit 限度的长度 * @return 指定长度的字符串 */ public static String readString(int limit) { return readKeyBoard(limit, false); } /** * 性能：读取键盘输入的指定长度的字符串或默认值，如果间接回车，返回默认值，否则返回字符串 * @param limit 限度的长度 * @param defaultValue 指定的默认值 * @return 指定长度的字符串 */ public static String readString(int limit, String defaultValue) { String str = readKeyBoard(limit, true); return str.equals("")? defaultValue : str; } /** * 性能：读取键盘输入的确认选项，Y或N * 将小的性能，封装到一个办法中. * @return Y或N */ public static char readConfirmSelection() { System.out.print("确认是否预订(Y/N): "); char c; for (; ; ) {//有限循环 //在这里，将承受到字符，转成了大写字母 //y => Y n=>N String str = readKeyBoard(1, false).toUpperCase(); c = str.charAt(0); if (c == 'Y' || c == 'N') { break; } else { System.out.print("抉择谬误，请从新输出："); } } return c; } /** * 性能： 读取一个字符串 * @param limit 读取的长度 * @param blankReturn 如果为true ,示意 能够读空字符串。 * 如果为false示意 不能读空字符串。 * * 如果输出为空，或者输出大于limit的长度，就会提醒从新输出。 * @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, 即用户没有输出任何内容，间接回车 if (line.length() == 0) { if (blankReturn) return line;//如果blankReturn=true,能够返回空串 else continue; //如果blankReturn=false,不承受空串，必须输出内容 } //如果用户输出的内容大于了 limit，就提醒重写输出 //如果用户如的内容 >0 <= limit ,我就承受 if (line.length() < 1 || line.length() > limit) { System.out.print("输出长度（不能大于" + limit + "）谬误，请从新输出："); 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 { //管制是否退出菜单 private boolean loop = true; private String key = ""; //接管用户的抉择 //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(); } //实现结账 public void payBill() { System.out.println("==============结账服务============"); System.out.print("请抉择要结账的餐桌编号(-1退出): "); int diningTableId = Utility.readInt(); if (diningTableId == -1) { System.out.println("=============勾销结账============"); 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; } //验证餐桌是否有须要结账的账单 if (!billService.hasPayBillByDiningTableId(diningTableId)) { System.out.println("=============该餐位没有未结账账单============"); return; } System.out.print("结账形式(现金/支付宝/微信)回车示意退出: "); String payMode = Utility.readString(20, "");//阐明如果回车，就是返回 "" if ("".equals(payMode)) { System.out.println("=============勾销结账============"); return; } char key = Utility.readConfirmSelection(); if (key == 'Y') { //结账 //调用咱们写的办法 if (billService.payBill(diningTableId, payMode)) { System.out.println("=============实现结账============"); } else { System.out.println("=============结账失败============"); } } else { System.out.println("=============勾销结账============"); } } //显示账单信息 public void listBill() {// List<Bill> bills = billService.list();// System.out.println("\n编号\t\t菜品号\t\t菜品量\t\t金额\t\t桌号\t\t日期\t\t\t\t\t\t\t状态");// for (Bill bill : bills) {// System.out.println(bill);// }// System.out.println("==============显示结束============"); List<MultiTableBean> multiTableBeans = billService.list2(); System.out.println("\n编号\t\t菜品号\t\t菜品量\t\t金额\t\t桌号\t\t日期\t\t\t\t\t\t\t状态\t\t菜品名\t\t价格"); for (MultiTableBean bill : multiTableBeans) { System.out.println(bill); } System.out.println("==============显示结束============"); } //实现点餐 public void orderMenu() { System.out.println("==============点餐服务============"); System.out.print("请输出点餐的桌号(-1退出): "); int orderDiningTableId = Utility.readInt(); if (orderDiningTableId == -1) { System.out.println("==============勾销点餐============"); return; } System.out.print("请输出点餐的菜品号(-1退出): "); int orderMenuId = Utility.readInt(); if (orderMenuId == -1) { System.out.println("==============勾销点餐============"); return; } System.out.print("请输出点餐的菜品量(-1退出): "); int orderNums = Utility.readInt(); if (orderNums == -1) { System.out.println("==============勾销点餐============"); 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("==============点餐胜利============"); } else { System.out.println("==============点餐失败============"); } } //显示所有菜品 public void listMenu() { List<Menu> list = menuService.list(); System.out.println("\n菜品编号\t\t菜品名\t\t类别\t\t价格"); for (Menu menu : list) { System.out.println(menu); } System.out.println("==============显示结束============"); } //实现订座 public void orderDiningTable() { System.out.println("==============预约餐桌============"); System.out.print("请抉择要预约的餐桌编号(-1退出): "); int orderId = Utility.readInt(); if (orderId == -1) { System.out.println("==============勾销预订餐桌============"); return; } //该办法失去的是 Y 或者 N char key = Utility.readConfirmSelection(); if (key == 'Y') {//要预约 //依据orderId 返回 对应DiningTable对象, 如果为null, 阐明该对象不存在 DiningTable diningTable = diningTableService.getDiningTableById(orderId); if (diningTable == null) {// System.out.println("==============预订餐桌不存在============"); return; } //判断该餐桌的状态是否 "空" if (!("空".equals(diningTable.getState()))) {//阐明以后这个餐桌不是 "空" 状态 System.out.println("==============该餐桌曾经预约或者就餐中============"); return; } //接管预约信息 System.out.print("预约人的名字: "); String orderName = Utility.readString(50); System.out.print("预约人的电话: "); String orderTel = Utility.readString(50); //更新餐桌状态 if (diningTableService.orderDiningTable(orderId, orderName, orderTel)) { System.out.println("==============预订餐桌胜利============"); } else { System.out.println("==============预订餐桌失败============"); } } else { System.out.println("==============勾销预订餐桌============"); } } //显示所有餐桌状态 public void listDiningTable() { List<DiningTable> list = diningTableService.list(); System.out.println("\n餐桌编号\t\t餐桌状态"); for (DiningTable diningTable : list) { System.out.println(diningTable); } System.out.println("==============显示结束============"); } //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("请输出你的抉择: "); key = Utility.readString(1); switch (key) { case "1": System.out.print("输出员工号: "); String empId = Utility.readString(50); System.out.print("输出密 码: "); String pwd = Utility.readString(50); Employee employee = employeeService.getEmployeeByIdAndPwd(empId, pwd); if (employee != null) { //阐明存在该用户 System.out.println("===============登录胜利[" + 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 预约餐桌"); 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("请输出你的抉择: "); key = Utility.readString(1); switch (key) { case "1": listDiningTable();//显示餐桌状态 break; case "2": orderDiningTable(); break; case "3": listMenu(); break; case "4": orderMenu(); break; case "5": listBill();//显示所有账单 break; case "6": payBill(); break; case "9": loop = false; break; default: System.out.println("你的输出有误，请从新输出"); break; } } } else { System.out.println("===============登录失败================"); } break; case "2": loop = false;// break; default: System.out.println("你输出有误，请从新输出."); } } System.out.println("你退出了满汉楼零碎~"); }}src/druid.properties
#key=valuedriverClassName=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/mhl?rewriteBatchedStatements=trueusername=rootpassword=hsp#initial connection SizeinitialSize=10#min idle connecton sizeminIdle=5#max active connection sizemaxActive=50#max wait time (5000 mil seconds)maxWait=5000mhl.iml
<?xml version="1.0" encoding="UTF-8"?><module type="JAVA_MODULE" version="4"> <component name="NewModuleRootManager" inherit-compiler-output="true"> <exclude-output /> <content url="file://$MODULE_DIR$"> <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" /> </content> <orderEntry type="inheritedJdk" /> <orderEntry type="sourceFolder" forTests="false" /> <orderEntry type="library" name="commons-dbutils-1.3" level="project" /> </component></module>多表查问思路
能够用MapListHandler实现：
https://www.pianshen.com/article/48341042440/
也能够另写MultiTabBean类，映射多个表，如上所示。