Java开发实例之图书管理系统的实现 Java开发实例之图书管理系统的

一、项目分布
二、代码展示

1.SQL语句
2.Book类
3.User类
4.用户分为两种

4.1NormalUser类
4.2Admin类

5.DBUtil类

6.BookDao类

7.UserDao类

8.operations包

8.1AddOperation类：增加书籍
8.2BorrowOperation类：借阅书籍
8.3DeleteOperation类:删除书籍
8.4DisplayOperation类：查看书籍列表
8.5ExitOperation类：退出系统
8.6FindOperation类：查找书籍
8.7ReturnOperation类：返还书籍

9.Main方法实现

三、结果实现

1.登录界面

2.普通用户操作

3.管理员操作

声明：本项目不涉及web操作，但需要了解java的基本语法和MySQL的基本语句运用。

一、项目分布

文章图片

db.sql类：SQL语句，在控制台执行，用于建立图书管理库。
Book类：定义了书的一些属性（书编号，书名，作者，价格，分类，状态）并且写了属性的get、set、toSting方法。
User类：定义了用户的一些属性（用户编号，用户名，密码和是否为管理员的标记），并且写了属性的get、set、toSting方法。
NormalUser类：描述普通用户，实现普通用户的构造方法，并打印普通用户的操作界面。
Admin类：描述管理员，实现管理员的构造方法并打印管理员的操作界面。
DBUtil类：封装与数据库建立连接的操作(主要用JDBC来编写)。
BookDao类：封装对表的增删查改操作。
UserDao类：封装识别用户的操作。

文章图片

operations包中定义了IOperation（操作）接口，这个包中的下面这些类都实现了这个IOperation接口（完成增删查改等操作）：

AddOperation类：增加书籍
BorrowOperation类：借阅书籍
DeleteOperation类:删除书籍
DisplayOperation类：查看书籍列表
ExitOperation类：退出系统
FindOperation类：查找书籍
ReturnOperation类：返还书籍

二、代码展示
1.SQL语句
在控制台执行，用于建立图书管理库（设置“张三”为普通用户，密码为321；“admin”为管理员，密码为123）

create database if not exists bookmanager; use bookmanager; -- 创建一个书籍表drop table if exists book; create table book(bookId int primary key auto_increment,name varchar(20),author varchar(20),-- 为了准确，价格以分为单位price int,type varchar(20),-- 如果isBorrowed为1，表示已经借出，为0，表示未借出isBorrowed int); -- 创建一个用户表（用户有管理员和普通用户两种）drop table if exists user; create table user(userId int primary key auto_increment,username varchar(20) unique,password varchar(20),-- 如果isAdmin 为1，表示是管理员，为0，表示是普通用户isAdmin int); -- 插入一些数据insert into book values(null,'西游记','吴承恩',10000,'古典小说',0); insert into book values(null, '三国演义', '罗贯中', 10000, '古典小说', 0); insert into book values(null, '水浒传', '施耐庵', 10000, '古典小说', 0); insert into book values(null, '金瓶梅', '兰陵笑笑生', 10000, '古典小说', 0); insert into book values(null,'三体','刘慈欣',10000,'科幻小说',0); -- 插入一些用户insert into user values(null,'admin','123',1); insert into user values(null,'张三','321',0);

2.Book类
定义了书的一些属性（书编号，书名，作者，价格，分类，状态）并且写了属性的get、set、toSting方法

package Java100_1006; //使用这个类来表示一本书// +------------+-------------+------+-----+---------+----------------+// | Field| Type| Null | Key | Default | Extra|// +------------+-------------+------+-----+---------+----------------+// | bookId| int(11)| NO| PRI | NULL| auto_increment |// | name| varchar(20) | YES|| NULL||// | author| varchar(20) | YES|| NULL||// | price| int(11)| YES|| NULL||// | type| varchar(20) | YES|| NULL||// | isBorrowed | int(11)| YES|| NULL||// +------------+-------------+------+-----+---------+----------------+public class Book {private int bookId; private String name; private String author; private int price; private String type; private boolean isBorrowed; public int getBookId() {return bookId; }public void setBookId(int bookId) {this.bookId = bookId; }public String getName() {return name; }public void setName(String name) {this.name = name; }public String getAuthor() {return author; }public void setAuthor(String author) {this.author = author; }public int getPrice() {return price; }public void setPrice(int price) {this.price = price; }public String getType() {return type; }public void setType(String type) {this.type = type; }public boolean isBorrowed() {return isBorrowed; }public void setBorrowed(boolean borrowed) {isBorrowed = borrowed; }@Overridepublic String toString() {return "Book{" +"bookId=" + bookId +", name='" + name + '\'' +", author='" + author + '\'' +", price=" + price +", type='" + type + '\'' +", isBorrowed=" + isBorrowed +'}'; }}

3.User类
定义了用户的一些属性（用户编号，用户名，密码和是否为管理员的标记），并且写了属性的get、set、toSting方法

package Java100_1006; import Java100_1006.operations.IOperation; abstract public class User {// 使用这个 User 类来表示一个用户// +----------+-------------+------+-----+---------+----------------+// | Field| Type| Null | Key | Default | Extra|// +----------+-------------+------+-----+---------+----------------+// | userId| int(11)| NO| PRI | NULL| auto_increment |// | username | varchar(20) | YES|| NULL||// | password | varchar(20) | YES|| NULL||// | isAdmin| int(11)| YES|| NULL||// +----------+-------------+------+-----+---------+----------------+// 针对此处的 isAdmin, 并不是直接使用一个 boolean 变量来区分, 而是使用两个不同的子类.// 原因是, 管理员和普通用户支持的方法, 是不一样的.private int userId; private String userName; private String passWord; // 包含了一个数组, 数组里面就是该用户支持的哪些操作.// 针对普通用户, 和管理员, 分别设置不同的操作.IOperation[] operations; //普通用户和管理员看到的菜单也不同abstract public int menu(); public int getUserId() {return userId; }public void setUserId(int userId) {this.userId = userId; }public String getUserName() {return userName; }public void setUserName(String userName) {this.userName = userName; }public String getPassWord() {return passWord; }public void setPassWord(String passWord) {this.passWord = passWord; }@Overridepublic String toString() {return "User{" +"userId=" + userId +", userName='" + userName + '\'' +", passWord='" + passWord + '\'' +'}'; }}

4.用户分为两种
普通用户和管理员，所以应该分别建立两个类来描述这两个用户。

4.1NormalUser类 **描述普通用户，实现普通用户的构造方法，并打印普通用户的操作界面。

package Java100_1006; import Java100_1006.operations.*; import java.util.Scanner; //普通用户public class NormalUser extends User{//普通用户的构造方法public NormalUser(){this.operations = new IOperation[]{//0.退出new ExitOperation(),//1.查看书籍列表new DisplayOperation(),//2. 查找指定书籍new FindOperation(),//3.借阅书籍new BorrowOperation(),//4. 归还书籍new ReturnOperation()}; }//打印普通用户的菜单@Overridepublic int menu() {System.out.println("============================="); System.out.println("欢迎您"+this.getUserName()+"!"); System.out.println("1. 查看书籍列表"); System.out.println("2. 查找指定书籍"); System.out.println("3. 借阅书籍"); System.out.println("4. 归还书籍"); System.out.println("0. 退出系统"); System.out.println("============================="); System.out.println("请输入您的选项："); Scanner scanner = new Scanner(System.in); int choice = scanner.nextInt(); return choice; }}

【Java开发实例之图书管理系统的实现】
4.2Admin类描述管理员，实现管理员的构造方法并打印管理员的操作界面

package Java100_1006; import Java100_1006.operations.*; import java.util.Scanner; //管理员public class Admin extends User{//管理员的构造方法public Admin(){//初始化operation//继承与User类，所以可以使用父类的中的数组this.operations = new IOperation[]{//0. 退出系统new ExitOperation(),//1. 查看书籍列表new DisplayOperation(),//2. 查找指定书籍new FindOperation(),//3. 新增书籍new AddOperation(),//4. 删除书籍new DeleteOperation()}; }//打印管理员的菜单@Overridepublic int menu() {System.out.println("================================"); System.out.println("欢迎您, " + this.getUserName() + "! 您是管理员! "); System.out.println("1. 查看书籍列表"); System.out.println("2. 查找指定书籍"); System.out.println("3. 新增书籍"); System.out.println("4. 删除书籍"); System.out.println("0. 退出系统"); System.out.println("================================"); System.out.println("请输入选项: "); Scanner scanner = new Scanner(System.in); int choice = scanner.nextInt(); return choice; }}

5.DBUtil类
封装与数据库建立连接的操作(主要用JDBC来编写)

package Java100_1006; import com.mysql.jdbc.jdbc2.optional.MysqlDataSource; import javax.sql.DataSource; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; //先建立这个类来封装数据库建立连接的操作//具体步骤：//1.创建DataSouse实例//2.根据DataSouse创建对应的Connectionpublic class DBUtil {private static final String URL = "jdbc:mysql://127.0.0.1:3306/bookmanager?characterEncoding=utf8&useSSL=false"; private static final String USERNAME = "root"; private static final String PASSWORD = "1234"; //懒汉模式：private static DataSource dataSource = null; //初始情况下，dataSource为null，没有被实例化//首次调用getDataSource()时才会被实例化private static DataSource getDataSource(){if(dataSource == null){dataSource = new MysqlDataSource(); ((MysqlDataSource)dataSource).setUrl(URL); ((MysqlDataSource)dataSource).setUser(USERNAME); ((MysqlDataSource)dataSource).setPassword(PASSWORD); }return dataSource; }//提供一个方法来建立连接//用static来修饰，那么就无需实例化DBUtil实例就能调用这个方法，更加方便public static Connection getConnection() throws SQLException {return getDataSource().getConnection(); }//释放资源public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet){try{if(resultSet != null){resultSet.close(); }if(statement != null){statement.close(); }if(connection != null){connection.close(); }}catch (SQLException e){e.printStackTrace(); }}}

6.BookDao类
封装对表的增删查改操作

package Java100_1006; import Java100_1006.Book; import Java100_1006.DBUtil; import java.sql.*; import java.util.ArrayList; import java.util.List; //封装对Book表的增删查改操作public class BookDao {//1.新增书籍（插入）public boolean add(Book book){//把book对象插入数据库的书籍表中Connection connection = null; PreparedStatement statement = null; try {//1.和数据库建立连接connection = DBUtil.getConnection(); //2.拼装sql语句String sql = "insert into book values(null,?,?,?,?,?)"; statement = connection.prepareStatement(sql); statement.setString(1,book.getName()); statement.setString(2,book.getAuthor()); statement.setInt(3,book.getPrice()); statement.setString(4,book.getType()); statement.setInt(5,book.isBorrowed()?1:0); //3.执行SQLint ret = statement.executeUpdate(); if(ret == 1)return true; return false; }catch (SQLException e){e.printStackTrace(); }finally {DBUtil.close(connection,statement,null); }return false; }//2.查找所有书籍（查找）public List selectAll() {List list = new ArrayList<>(); Connection connection = null; PreparedStatement statement = null; ResultSet resultSet = null; try {//1.与数据库建立连接connection = DBUtil.getConnection(); //2.拼装SQLString sql = "select * from book"; statement = connection.prepareStatement(sql); //3.执行SQLresultSet = statement.executeQuery(); //4.遍历结果集合while(resultSet.next()){//取出当前行的这些列，构造一个Book对象来Book book = new Book(); book.setBookId(resultSet.getInt("bookId")); book.setName(resultSet.getString("name")); book.setAuthor(resultSet.getString("author")); book.setPrice(resultSet.getInt("price")); book.setType(resultSet.getString("type")); book.setBorrowed(resultSet.getInt("isBorrowed")==1); //把这个book对象添加到链表中list.add(book); }} catch (SQLException e) {e.printStackTrace(); }finally {DBUtil.close(connection,statement,resultSet); }return list; }//3.根据名字查找书籍（查找）public List selectByName(String name){List list = new ArrayList<>(); Connection connection = null; PreparedStatement statement = null; ResultSet resultSet = null; try {//1.先与数据库建立连接connection = DBUtil.getConnection(); //2.拼装SQL语句String sql = "select * from book where name=?"; statement = connection.prepareStatement(sql); statement.setString(1,name); //3.执行SQLresultSet = statement.executeQuery(); //4.遍历结果集合while(resultSet.next()){Book book = new Book(); book.setBookId(resultSet.getInt("bookId")); book.setName(resultSet.getString("name")); book.setAuthor(resultSet.getString("author")); book.setPrice(resultSet.getInt("price")); book.setType(resultSet.getString("type")); book.setBorrowed(resultSet.getInt("isBorrowed") == 1); list.add(book); }} catch (SQLException e) {e.printStackTrace(); }finally {DBUtil.close(connection,statement,resultSet); }return list; }//4.删除书籍（删除）public boolean delete(int bookId){Connection connection = null; PreparedStatement statement = null; try {//1.建立连接connection = DBUtil.getConnection(); //2.拼装SQLString sql = "delete from book where bookId=?"; statement = connection.prepareStatement(sql); statement.setInt(1,bookId); //3.执行SQLint ret = statement.executeUpdate(); if(ret != 1){returnfalse; }return true; } catch (SQLException e) {e.printStackTrace(); }finally {DBUtil.close(connection,statement,null); }return false; }//5.借书（修改）public boolean borrowBook(int bookId){Connection connection = null; //statement1用于查找操作PreparedStatement statement1 = null; //statement2用于修改操作PreparedStatement statement2 = null; ResultSet resultSet = null; try {//1.建立连接connection = DBUtil.getConnection(); //要借书，就必须知道这本书存不存在，所以我们先查找，再操作//2.拼装SQLString sql = "select * from book where bookId=?"; statement1 = connection.prepareStatement(sql); statement1.setInt(1,bookId); //3.执行SQLresultSet = statement1.executeQuery(); //4.遍历结果，预期结果要么是1条，要么是0条if(resultSet.next()){//进入if就说明书是存在的boolean isBorrowed = (resultSet.getInt("isBorrowed")==1); if(isBorrowed) {//说明书已经被借出了，不能再次借阅System.out.println("书已经借出! 无法再次借出! bookId = " + bookId); return false; }}else{//进入else，那么书是不存在的System.out.println("书不存在! 无法借出! bookId = " + bookId); return false; }//[接下来是开始进行借书逻辑]//5.拼装SQLsql = "update book set isBorrowed=1 where bookId=?"; statement2 = connection.prepareStatement(sql); statement2.setInt(1,bookId); //6.执行SQLint ret = statement2.executeUpdate(); if(ret != 1){return false; }return true; } catch (SQLException e) {e.printStackTrace(); }finally {if(resultSet != null){try {resultSet.close(); } catch (SQLException e) {e.printStackTrace(); }}if(statement2 != null){try {statement2.close(); } catch (SQLException e) {e.printStackTrace(); }}if(statement1 != null){try {statement1.close(); } catch (SQLException e) {e.printStackTrace(); }}if (connection != null){try {connection.close(); } catch (SQLException e) {e.printStackTrace(); }}}return false; }//6.还书（修改）public boolean returnBook(int bookId){Connection connection = null; PreparedStatement statement1 = null; PreparedStatement statement2 = null; ResultSet resultSet = null; try {connection = DBUtil.getConnection(); //查询书是否存在String sql = "select * from book where bookId=?"; statement1 = connection.prepareStatement(sql); statement1.setInt(1,bookId); resultSet = statement1.executeQuery(); if(resultSet.next()){//进入if语句就说明这本书存在于书籍名单中boolean isBorrowed = (resultSet.getInt("isBorrowed")==1); if(!isBorrowed){System.out.println("书没有借出, 没必要还! bookId = " + bookId); return false; }}else{//不是图书系统中的书，不需要还System.out.println("书不存在, 无法归还! bookId = " + bookId); return false; }//[还书]//修改书籍的借出状态就可sql = "update book set isBorrowed=0 where bookId=?"; statement2 = connection.prepareStatement(sql); statement2.setInt(1,bookId); int ret = statement2.executeUpdate(); if(ret != 1){return false; }return true; } catch (SQLException e) {e.printStackTrace(); }finally {if(resultSet != null){try {resultSet.close(); } catch (SQLException e) {e.printStackTrace(); }}if(statement2 != null){try {statement2.close(); } catch (SQLException e) {e.printStackTrace(); }}if(statement1 != null){try {statement1.close(); } catch (SQLException e) {e.printStackTrace(); }}if (connection != null){try {connection.close(); } catch (SQLException e) {e.printStackTrace(); }}}return false; }}

7.UserDao类
封装识别用户的操作

package Java100_1006; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class UserDao {//实现根据用户名找密码这样一个过程（用户名唯一）public User selectByName(String name){Connection connection = null; PreparedStatement statement = null; ResultSet resultSet = null; try {connection = DBUtil.getConnection(); String sql = "select * from user where username=?"; statement = connection.prepareStatement(sql); statement.setString(1,name); resultSet = statement.executeQuery(); if(resultSet.next()){//存在这个用户，返回一个User对象//判断这个用户是普通用户还是管理员boolean isAdmin = (resultSet.getInt("isAdmin"))==1; User user = null; if (isAdmin){user = new Admin(); }else{user = new NormalUser(); }user.setUserId(resultSet.getInt("userId")); user.setUserName(resultSet.getString("username")); user.setPassWord(resultSet.getString("password")); return user; }} catch (SQLException e) {e.printStackTrace(); }finally {DBUtil.close(connection,statement,resultSet); }return null; }}

8.operations包
创建IOperation接口和实现这个接口的其他类
接口：

package Java100_1006.operations; //后续的增加删除借书还书等操作都要实现这个接口public interface IOperation {void work(); }

8.1AddOperation类：增加书籍

package Java100_1006.operations; import Java100_1006.Book; import Java100_1006.BookDao; import java.util.Scanner; public class AddOperation implements IOperation{@Overridepublic void work() {System.out.println("新增书籍！"); Scanner scanner= new Scanner(System.in); System.out.println("请输入书名: "); String bookName = scanner.next(); System.out.println("请输入作者: "); String author = scanner.next(); System.out.println("请输入价格:"); int price = scanner.nextInt(); System.out.println("请输入类别:"); String type = scanner.next(); //假设新增书籍都是未借出的状态Book book = new Book(); book.setName(bookName); book.setAuthor(author); book.setPrice(price); book.setType(type); BookDao bookDao = new BookDao(); boolean ret = bookDao.add(book); if(ret){System.out.println("新增书籍成功"); }else{System.out.println("新增书籍失败!"); }}}

8.2BorrowOperation类：借阅书籍

package Java100_1006.operations; import Java100_1006.BookDao; import java.util.Scanner; public class BorrowOperation implements IOperation{@Overridepublic void work() {System.out.println("借阅书籍!"); Scanner scanner = new Scanner(System.in); System.out.println("请输入要借阅的书籍id:"); int bookId = scanner.nextInt(); BookDao bookDao = new BookDao(); boolean ret = bookDao.borrowBook(bookId); if (ret) {System.out.println("借阅书籍成功!"); } else {System.out.println("借阅书籍失败!"); }}}

8.3DeleteOperation类:删除书籍

package Java100_1006.operations; import Java100_1006.BookDao; import java.util.Scanner; public class DeleteOperation implements IOperation{@Overridepublic void work() {System.out.println("删除书籍!"); Scanner scanner = new Scanner(System.in); System.out.println("请输入要删除的书籍id: "); int bookId = scanner.nextInt(); BookDao bookDao = new BookDao(); boolean ret = bookDao.delete(bookId); if (ret) {System.out.println("删除成功!"); } else {System.out.println("删除失败!"); }}}

8.4DisplayOperation类：查看书籍列表

package Java100_1006.operations; import Java100_1006.Book; import Java100_1006.BookDao; import java.util.List; public class DisplayOperation implements IOperation{@Overridepublic void work() {System.out.println("展示所有书籍！"); BookDao bookDao = new BookDao(); List books = bookDao.selectAll(); for(Book book:books){System.out.println(book); }System.out.println("展示所有书籍完毕！"); }}

8.5ExitOperation类：退出系统

package Java100_1006.operations; //退出操作public class ExitOperation implements IOperation{@Overridepublic void work() {System.out.println("退出程序"); System.exit(0); }}

8.6FindOperation类：查找书籍

package Java100_1006.operations; import Java100_1006.Book; import Java100_1006.BookDao; import java.util.ArrayList; import java.util.List; import java.util.Scanner; public class FindOperation implements IOperation{@Overridepublic void work() {System.out.println("根据名字查找书籍!"); System.out.println("请输入要查找的书名: "); Scanner scanner = new Scanner(System.in); String bookName = scanner.next(); BookDao bookDao = new BookDao(); List books = bookDao.selectByName(bookName); for(Book book:books){System.out.println(book); }System.out.println("根据名字查找书籍完毕!"); }}

8.7ReturnOperation类：返还书籍

package Java100_1006.operations; import Java100_1006.BookDao; import java.util.Scanner; public class ReturnOperation implements IOperation{@Overridepublic void work() {System.out.println("归还书籍!"); Scanner scanner = new Scanner(System.in); System.out.println("请输入要归还的书籍id:"); int bookId = scanner.nextInt(); BookDao bookDao = new BookDao(); boolean ret = bookDao.returnBook(bookId); if (ret) {System.out.println("归还书籍成功!"); } else {System.out.println("归还书籍失败!"); }}}

9.Main方法实现

package Java100_1006; import java.util.Scanner; //编写系统的主体逻辑public class Main {public static void main(String[] args) {//通过login方法进行登录User user = login(); while(true){int choice = user.menu(); user.doOperation(choice); }}private static User login() {//1.实现用户登录逻辑Scanner scanner = new Scanner(System.in); System.out.println("请输入用户名："); String userName = scanner.next(); System.out.println("请输入密码："); String passWord = scanner.next(); //2.从数据库根据用户名查询密码UserDao userDao = new UserDao(); User user = userDao.selectByName(userName); if(user == null){//不存在该用户System.out.println("登陆失败!"); // 直接退出程序System.exit(0); }if(!user.getPassWord().equals(passWord)){//密码不正确System.out.println("登陆失败"); System.exit(0); }return user; }}

三、结果实现
1.登录界面