Java開發(fā)實(shí)例之圖書管理系統(tǒng)的實(shí)現(xiàn)

更新時(shí)間：2021年10月08日 09:13:08 作者：小玄ｋｓ

圖書管理的功能大體包括：增加書籍、借閱書籍、刪除書籍、查看書籍列表、退出系統(tǒng)、查找書籍、返還書籍這些，本文主要給大家介紹該系統(tǒng)的數(shù)據(jù)庫語句，對(duì)大家的學(xué)習(xí)或工作具有一定的參考借鑒價(jià)值，需要的朋友可以參考下

聲明：本項(xiàng)目不涉及web操作，但需要了解java的基本語法和MySQL的基本語句運(yùn)用。

一、項(xiàng)目分布

在這里插入圖片描述

db.sql類：SQL語句，在控制臺(tái)執(zhí)行，用于建立圖書管理庫。
Book類：定義了書的一些屬性（書編號(hào)，書名，作者，價(jià)格，分類，狀態(tài)）并且寫了屬性的get、set、toSting方法。
User類：定義了用戶的一些屬性（用戶編號(hào)，用戶名，密碼和是否為管理員的標(biāo)記），并且寫了屬性的get、set、toSting方法。
NormalUser類：描述普通用戶，實(shí)現(xiàn)普通用戶的構(gòu)造方法，并打印普通用戶的操作界面。
Admin類：描述管理員，實(shí)現(xiàn)管理員的構(gòu)造方法并打印管理員的操作界面。
DBUtil類：封裝與數(shù)據(jù)庫建立連接的操作(主要用JDBC來編寫)。
BookDao類：封裝對(duì)表的增刪查改操作。
UserDao類：封裝識(shí)別用戶的操作。

在這里插入圖片描述

operations包中定義了IOperation（操作）接口，這個(gè)包中的下面這些類都實(shí)現(xiàn)了這個(gè)IOperation接口（完成增刪查改等操作）：

AddOperation類：增加書籍
BorrowOperation類：借閱書籍
DeleteOperation類:刪除書籍
DisplayOperation類：查看書籍列表
ExitOperation類：退出系統(tǒng)
FindOperation類：查找書籍
ReturnOperation類：返還書籍

二、代碼展示

1.SQL語句

在控制臺(tái)執(zhí)行，用于建立圖書管理庫（設(shè)置“張三”為普通用戶，密碼為321；“admin”為管理員，密碼為123）

create database if not exists bookmanager;

use bookmanager;

-- 創(chuàng)建一個(gè)書籍表
drop table if exists book;
create table book(
    bookId int primary key auto_increment,
    name varchar(20),
    author varchar(20),
    -- 為了準(zhǔn)確，價(jià)格以 分 為單位
    price int,
    type varchar(20),
    -- 如果isBorrowed為1，表示已經(jīng)借出，為0，表示未借出
    isBorrowed int
);

-- 創(chuàng)建一個(gè)用戶表（用戶有管理員和普通用戶兩種）
drop table if exists user;
create table user(
    userId int primary key auto_increment,
    username varchar(20) unique,
    password varchar(20),
    -- 如果isAdmin 為1，表示是管理員，為0，表示是普通用戶
    isAdmin int
);

-- 插入一些數(shù)據(jù)
insert into book values(null,'西游記','吳承恩',10000,'古典小說',0);
insert into book values(null, '三國演義', '羅貫中', 10000, '古典小說', 0);
insert into book values(null, '水滸傳', '施耐庵', 10000, '古典小說', 0);
insert into book values(null, '金瓶梅', '蘭陵笑笑生', 10000, '古典小說', 0);
insert into book values(null,'三體','劉慈欣',10000,'科幻小說',0);

-- 插入一些用戶
insert into user values(null,'admin','123',1);
insert into user values(null,'張三','321',0);

2.Book類

定義了書的一些屬性（書編號(hào)，書名，作者，價(jià)格，分類，狀態(tài)）并且寫了屬性的get、set、toSting方法

package Java100_1006;

//使用這個(gè)類來表示一本書
// +------------+-------------+------+-----+---------+----------------+
// | 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;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bookId=" + bookId +
                ", name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ", isBorrowed=" + isBorrowed +
                '}';
    }
}

3.User類

定義了用戶的一些屬性（用戶編號(hào)，用戶名，密碼和是否為管理員的標(biāo)記），并且寫了屬性的get、set、toSting方法

package Java100_1006;

import Java100_1006.operations.IOperation;

abstract public class User {
    // 使用這個(gè) User 類來表示一個(gè)用戶
// +----------+-------------+------+-----+---------+----------------+
// | 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    |                |
// +----------+-------------+------+-----+---------+----------------+
    // 針對(duì)此處的 isAdmin, 并不是直接使用一個(gè) boolean 變量來區(qū)分, 而是使用兩個(gè)不同的子類.
    // 原因是, 管理員和普通用戶支持的方法, 是不一樣的.
    private int userId;
    private String userName;
    private String passWord;

    // 包含了一個(gè)數(shù)組, 數(shù)組里面就是該用戶支持的哪些操作.
    // 針對(duì)普通用戶, 和管理員, 分別設(shè)置不同的操作.
    IOperation[] operations;

    //普通用戶和管理員看到的菜單也不同
    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;
    }

    @Override
    public String toString() {
        return "User{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", passWord='" + passWord + '\'' +
                '}';
    }
}

4.用戶分為兩種

普通用戶和管理員，所以應(yīng)該分別建立兩個(gè)類來描述這兩個(gè)用戶。

4.1NormalUser類

**描述普通用戶，實(shí)現(xiàn)普通用戶的構(gòu)造方法，并打印普通用戶的操作界面。

package Java100_1006;

import Java100_1006.operations.*;

import java.util.Scanner;

//普通用戶
public class NormalUser extends User{
    //普通用戶的構(gòu)造方法
    public NormalUser(){
        this.operations = new IOperation[]{
            	//0.退出
                new ExitOperation(),
            	//1.查看書籍列表
                new DisplayOperation(),
            	//2. 查找指定書籍
                new FindOperation(),
            	//3.借閱書籍
                new BorrowOperation(),
            	//4. 歸還書籍
                new ReturnOperation()
        };
    }

    //打印普通用戶的菜單
    @Override
    public int menu() {
        System.out.println("=============================");
        System.out.println("歡迎您"+this.getUserName()+"!");
        System.out.println("1. 查看書籍列表");
        System.out.println("2. 查找指定書籍");
        System.out.println("3. 借閱書籍");
        System.out.println("4. 歸還書籍");
        System.out.println("0. 退出系統(tǒng)");
        System.out.println("=============================");
        System.out.println("請(qǐng)輸入您的選項(xiàng)：");
        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        return choice;
    }
}

4.2Admin類

描述管理員，實(shí)現(xiàn)管理員的構(gòu)造方法并打印管理員的操作界面

package Java100_1006;

import Java100_1006.operations.*;

import java.util.Scanner;

//管理員
public class Admin extends User{
    //管理員的構(gòu)造方法
    public Admin(){
        //初始化operation
        //繼承與User類，所以可以使用父類的中的數(shù)組
        this.operations = new IOperation[]{
            	//0. 退出系統(tǒng)
                new ExitOperation(),
           	 	//1. 查看書籍列表
                new DisplayOperation(),
            	//2. 查找指定書籍
                new FindOperation(),
            	//3. 新增書籍
                new AddOperation(),
            	//4. 刪除書籍
                new DeleteOperation()
        };
    }
    //打印管理員的菜單
    @Override
    public int menu() {
        System.out.println("================================");
        System.out.println("歡迎您, " + this.getUserName() + "! 您是管理員! ");
        System.out.println("1. 查看書籍列表");
        System.out.println("2. 查找指定書籍");
        System.out.println("3. 新增書籍");
        System.out.println("4. 刪除書籍");
        System.out.println("0. 退出系統(tǒng)");
        System.out.println("================================");
        System.out.println("請(qǐng)輸入選項(xiàng): ");
        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        return choice;
    }
}

5.DBUtil類

封裝與數(shù)據(jù)庫建立連接的操作(主要用JDBC來編寫)

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;

//先建立這個(gè)類來 封裝 數(shù)據(jù)庫建立連接的操作
//具體步驟：
//1.創(chuàng)建DataSouse實(shí)例
//2.根據(jù)DataSouse創(chuàng)建對(duì)應(yīng)的Connection
public 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";

    //懶漢模式：
    private static DataSource dataSource = null;

    //初始情況下，dataSource為null，沒有被實(shí)例化
    //首次調(diào)用getDataSource()時(shí)才會(huì)被實(shí)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;
    }

    //提供一個(gè)方法來建立連接
    //用static來修飾，那么就無需實(shí)例化DBUtil實(shí)例就能調(diào)用這個(gè)方法，更加方便
    public static Connection getConnection() throws SQLException {
        return getDataSource().getConnection();
    }

    //釋放資源
    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類

封裝對(duì)表的增刪查改操作

package Java100_1006;

import Java100_1006.Book;
import Java100_1006.DBUtil;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

//封裝 對(duì)Book表的增刪查改操作
public class BookDao {

    //1.新增書籍（插入）
    public boolean add(Book book){
        //把book對(duì)象插入數(shù)據(jù)庫的書籍表中
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            //1.和數(shù)據(jù)庫建立連接
            connection = DBUtil.getConnection();

            //2.拼裝sql語句
            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.執(zhí)行SQL
            int ret = statement.executeUpdate();
            if(ret == 1)
                return true;
            return false;

        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            DBUtil.close(connection,statement,null);
        }
        return false;
    }
    //2.查找所有書籍（查找）
    public List<Book> selectAll() {
        List<Book> list = new ArrayList<>();
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        try {
            //1.與數(shù)據(jù)庫建立連接
            connection = DBUtil.getConnection();
            //2.拼裝SQL
            String sql = "select * from book";
            statement = connection.prepareStatement(sql);
            //3.執(zhí)行SQL
            resultSet = statement.executeQuery();
            //4.遍歷結(jié)果集合
            while(resultSet.next()){
                //取出當(dāng)前行的這些列，構(gòu)造一個(gè)Book對(duì)象來
                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);
                //把這個(gè)book對(duì)象添加到鏈表中
                list.add(book);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(connection,statement,resultSet);
        }
        return list;
    }
    //3.根據(jù)名字查找書籍（查找）
    public List<Book> selectByName(String name){
        List<Book> list = new ArrayList<>();
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        try {
            //1.先與數(shù)據(jù)庫建立連接
            connection = DBUtil.getConnection();
            //2.拼裝SQL語句
            String sql = "select * from book where name=?";
            statement = connection.prepareStatement(sql);
            statement.setString(1,name);
            //3.執(zhí)行SQL
            resultSet = statement.executeQuery();
            //4.遍歷結(jié)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.刪除書籍（刪除）
    public boolean delete(int bookId){
     Connection connection = null;
     PreparedStatement statement = null;
        try {
            //1.建立連接
            connection = DBUtil.getConnection();
            //2.拼裝SQL
            String sql = "delete from book where bookId=?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1,bookId);
            //3.執(zhí)行SQL
            int ret = statement.executeUpdate();
            if(ret != 1){
                return  false;
            }
            return true;
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(connection,statement,null);
        }
        return false;
    }
    //5.借書（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.建立連接
            connection = DBUtil.getConnection();
            //要借書，就必須知道這本書存不存在，所以我們先查找，再操作
            //2.拼裝SQL
            String sql = "select * from book where bookId=?";
            statement1 = connection.prepareStatement(sql);
            statement1.setInt(1,bookId);
            //3.執(zhí)行SQL
            resultSet = statement1.executeQuery();
            //4.遍歷結(jié)果，預(yù)期結(jié)果要么是1條，要么是0條
            if(resultSet.next()){
                //進(jìn)入if就說明書是存在的
                boolean isBorrowed = (resultSet.getInt("isBorrowed")==1);
                if(isBorrowed) {
                    //說明書已經(jīng)被借出了，不能再次借閱
                    System.out.println("書已經(jīng)借出! 無法再次借出! bookId = " + bookId);
                    return false;
                }
            }else{
                //進(jìn)入else，那么書是不存在的
                System.out.println("書不存在! 無法借出! bookId = " + bookId);
                return false;
            }
            //[接下來是開始進(jìn)行借書邏輯]
            //5.拼裝SQL
            sql = "update book set isBorrowed=1 where bookId=?";
            statement2 = connection.prepareStatement(sql);
            statement2.setInt(1,bookId);

            //6.執(zhí)行SQL
            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;
    }
    //6.還書（修改）
    public boolean returnBook(int bookId){
        Connection connection = null;
        PreparedStatement statement1 = null;
        PreparedStatement statement2 = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            //查詢書是否存在
            String sql = "select * from book where bookId=?";
            statement1 = connection.prepareStatement(sql);
            statement1.setInt(1,bookId);
            resultSet = statement1.executeQuery();
            if(resultSet.next()){
                //進(jìn)入if語句就說明這本書存在于書籍名單中
                boolean isBorrowed = (resultSet.getInt("isBorrowed")==1);
                if(!isBorrowed){
                    System.out.println("書沒有借出, 沒必要還! bookId = " + bookId);
                    return false;
                }
            }else{
                //不是圖書系統(tǒng)中的書，不需要還
                System.out.println("書不存在, 無法歸還! bookId = " + bookId);
                return false;
            }
            //[還書]
            //修改書籍的借出狀態(tài)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類

封裝識(shí)別用戶的操作

package Java100_1006;


import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class UserDao {
    //實(shí)現(xiàn)根據(jù)用戶名找密碼這樣一個(gè)過程（用戶名 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()){
                //存在這個(gè)用戶，返回一個(gè)User對(duì)象
                //判斷這個(gè)用戶是普通用戶還是管理員
                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

創(chuàng)建IOperation接口和實(shí)現(xiàn)這個(gè)接口的其他類

接口：

package Java100_1006.operations;

//后續(xù)的增加 刪除  借書 還書 等操作都要實(shí)現(xiàn)這個(gè)接口
public interface IOperation {
    void work();
}

8.1AddOperation類：增加書籍

package Java100_1006.operations;

import Java100_1006.Book;
import Java100_1006.BookDao;

import java.util.Scanner;

public class AddOperation implements IOperation{
    @Override
    public void work() {
        System.out.println("新增書籍！");
        Scanner scanner  = new Scanner(System.in);
        System.out.println("請(qǐng)輸入書名: ");
        String bookName = scanner.next();
        System.out.println("請(qǐng)輸入作者: ");
        String author = scanner.next();
        System.out.println("請(qǐng)輸入價(jià)格:");
        int price = scanner.nextInt();
        System.out.println("請(qǐng)輸入類別:");
        String type = scanner.next();
        //假設(shè)新增書籍都是未借出的狀態(tài)
        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("新增書籍成功");
        }else{
            System.out.println("新增書籍失敗!");
        }
    }
}

8.2BorrowOperation類：借閱書籍

package Java100_1006.operations;

import Java100_1006.BookDao;

import java.util.Scanner;

public class BorrowOperation implements IOperation{
    @Override
    public void work() {
        System.out.println("借閱書籍!");
        Scanner scanner = new Scanner(System.in);
        System.out.println("請(qǐng)輸入要借閱的書籍id:");
        int bookId = scanner.nextInt();
        BookDao bookDao = new BookDao();
        boolean ret = bookDao.borrowBook(bookId);
        if (ret) {
            System.out.println("借閱書籍成功!");
        } else {
            System.out.println("借閱書籍失敗!");
        }
    }
}

8.3DeleteOperation類:刪除書籍

package Java100_1006.operations;

import Java100_1006.BookDao;

import java.util.Scanner;

public class DeleteOperation implements IOperation{
    @Override
    public void work() {
        System.out.println("刪除書籍!");
        Scanner scanner = new Scanner(System.in);
        System.out.println("請(qǐng)輸入要?jiǎng)h除的書籍id: ");
        int bookId = scanner.nextInt();

        BookDao bookDao = new BookDao();
        boolean ret = bookDao.delete(bookId);
        if (ret) {
            System.out.println("刪除成功!");
        } else {
            System.out.println("刪除失敗!");
        }
    }
}

8.4DisplayOperation類：查看書籍列表

package Java100_1006.operations;

import Java100_1006.Book;
import Java100_1006.BookDao;

import java.util.List;

public class DisplayOperation implements IOperation{
    @Override
    public void work() {
        System.out.println("展示所有書籍！");
        BookDao bookDao = new BookDao();
        List<Book> books = bookDao.selectAll();
        for(Book book:books){
            System.out.println(book);
        }
        System.out.println("展示所有書籍完畢！");
    }
}

8.5ExitOperation類：退出系統(tǒng)

package Java100_1006.operations;

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

8.6FindOperation類：查找書籍

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{
    @Override
    public void work() {
        System.out.println("根據(jù)名字查找書籍!");
        System.out.println("請(qǐng)輸入要查找的書名: ");
        Scanner scanner = new Scanner(System.in);
        String bookName = scanner.next();
        BookDao bookDao = new BookDao();
        List<Book> books = bookDao.selectByName(bookName);
        for(Book book:books){
            System.out.println(book);
        }
        System.out.println("根據(jù)名字查找書籍完畢!");
    }
}

8.7ReturnOperation類：返還書籍

package Java100_1006.operations;

import Java100_1006.BookDao;

import java.util.Scanner;

public class ReturnOperation implements IOperation{
    @Override
    public void work() {
        System.out.println("歸還書籍!");
        Scanner scanner = new Scanner(System.in);
        System.out.println("請(qǐng)輸入要?dú)w還的書籍id:");
        int bookId = scanner.nextInt();
        BookDao bookDao = new BookDao();
        boolean ret = bookDao.returnBook(bookId);
        if (ret) {
            System.out.println("歸還書籍成功!");
        } else {
            System.out.println("歸還書籍失敗!");
        }
    }
}

9.Main方法實(shí)現(xiàn)

package Java100_1006;

import java.util.Scanner;

//編寫系統(tǒng)的主體邏輯
public class Main {
    public static void main(String[] args) {
        //通過login方法進(jìn)行登錄
        User user = login();
        while(true){
            int choice = user.menu();
            user.doOperation(choice);
        }
    }

    private static User login() {
        //1.實(shí)現(xiàn)用戶登錄邏輯
        Scanner scanner = new Scanner(System.in);
        System.out.println("請(qǐng)輸入用戶名：");
        String userName = scanner.next();
        System.out.println("請(qǐng)輸入密碼：");
        String passWord = scanner.next();
        //2.從數(shù)據(jù)庫根據(jù)用戶名查詢密碼
        UserDao userDao = new UserDao();
        User user = userDao.selectByName(userName);
        if(user == null){
            //不存在該用戶
            System.out.println("登陸失敗!");
            // 直接退出程序
            System.exit(0);
        }
        if(!user.getPassWord().equals(passWord)){
            //密碼不正確
            System.out.println("登陸失敗");
            System.exit(0);
        }
        return user;
    }
}