Java 数据库项目之满汉楼
作者：timerring
- 2023-05-16 山东
本文字数：20968 字
阅读完需：约 69 分钟
文章和代码已经归档至【Github 仓库：https://github.com/timerring/java-tutorial 】或者公众号【AIShareLab】回复 java 也可获取。
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, 1
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Java
`-- 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.properties
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src/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<T> { //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<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<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); } }
}
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src/com/hspedu/mhl/dao/BillDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.Bill;public class BillDAO extends BasicDAO<Bill> {}
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src/com/hspedu/mhl/dao/DiningTableDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.DiningTable;
public class DiningTableDAO extends BasicDAO<DiningTable> { //如果有特别的操作，可以写在 DiningTableDAO}
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src/com/hspedu/mhl/dao/EmployeeDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.Employee;
public class EmployeeDAO extends BasicDAO<Employee> { //这里还可以写特有的操作.}
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src/com/hspedu/mhl/dao/MenuDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.Menu;
public class MenuDAO extends BasicDAO<Menu> {}
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src/com/hspedu/mhl/dao/MultiTableDAO.java
package com.hspedu.mhl.dao;
import com.hspedu.mhl.domain.MultiTableBean;
public class MultiTableDAO extends BasicDAO<MultiTableBean> {}
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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 + "\t\t" + menuId + "\t\t\t" + nums + "\t\t\t" + money + "\t" + diningTableId + "\t\t" + billDate + "\t\t" + state ; }}
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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 + "\t\t\t" + state; }}
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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; }}
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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 + "\t\t\t" + name + "\t\t" + type + "\t\t" + price; }}
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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 + "\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; }}
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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 <= 0) { return false; }
//需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; }
//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 <= 0) { //如果更新没有成功，则表示失败... return false; } //2. 修改diningTable表 //注意：不要直接在这里操作，而应该调用DiningTableService 方法,完成更新，体现各司其职
if(!diningTableService.updateDiningTableToFree(diningTableId, "空")) { return false; } return true; }}
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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); }
//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; }
}
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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);
}}
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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 List<Menu> list() { return menuDAO.queryMulti("select * from menu", Menu.class); }
//需要方法，根据id, 返回Menu对象 public Menu getMenuById(int id) { return menuDAO.querySingle("select * from menu where id = ?", Menu.class, id); }}
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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); } }}
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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<=2位 try { n = Integer.parseInt(str);//将字符串转换成整数 break; } catch (NumberFormatException e) { System.out.print("数字输入错误，请重新输入："); } } return n; } /** * 功能：读取键盘输入的 整数或默认值，如果直接回车，则返回默认值，否则返回输入的整数 * @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; } //异常处理... try { n = Integer.parseInt(str); break; } catch (NumberFormatException e) { System.out.print("数字输入错误，请重新输入："); } } return n; }
/** * 功能：读取键盘输入的指定长度的字符串 * @param limit 限制的长度 * @return 指定长度的字符串 */
public static String readString(int limit) { return readKeyBoard(limit, false); }
/** * 功能：读取键盘输入的指定长度的字符串或默认值，如果直接回车，返回默认值，否则返回字符串 * @param limit 限制的长度 * @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; }
/** * 功能：读取键盘输入的确认选项，Y或N * 将小的功能，封装到一个方法中. * @return Y或N */ public static char readConfirmSelection() { System.out.print("确认是否预订(Y/N): "); char c; for (; ; ) {//无限循环 //在这里，将接受到字符，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("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 ,我就接受 if (line.length() < 1 || line.length() > limit) { System.out.print("输入长度（不能大于" + limit + "）错误，请重新输入："); continue; } break; }
return line; }}
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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<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("==============显示完毕============");
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() { 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("==============显示完毕============"); }
//完成订座 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
//根据orderId 返回 对应DiningTable对象, 如果为null, 说明该对象不存在 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()))) {//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 (diningTableService.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============"); }
}
//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("==============显示完毕============"); }
//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": 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("你的输入有误，请重新输入"); break; } } } else { System.out.println("===============登录失败================"); } break; case "2": loop = false;// break; default: System.out.println("你输入有误，请重新输入."); } } System.out.println("你退出了满汉楼系统~"); }
}
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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=5000
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mhl.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>
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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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版权声明: 本文为 InfoQ 作者【timerring】的原创文章。
原文链接:【http://xie.infoq.cn/article/22e0f9acb986a9d0c51f8338f】。未经作者许可，禁止转载。
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