Java图书管理代码

一：简介
二：核心需求
三: 类的设计
- 1. 创建图书相关的类
- 2. 创建操作相关的类
- 3. 创建用户相关的类
- 4. 进行整合
5. 实现具体的每个 Operation

大家好，我是晓星航。今天为大家带来的是Java语言图书馆里系统的相关的讲解！😀

一：简介

利用所学的知识点：类，抽象类，封装，继承，多态，接口等进行的一个简单的代码练习。

二：核心需求

1、简单的登录

2、管理端

整理书籍(该功能为可扩展功能)
查阅书籍
增加书籍
删除书籍
打印书籍列表
退出

3、用户端

查询书籍
借阅书籍
归还书籍
退出

整体功能概括图：

三: 类的设计

1. 创建图书相关的类

先创建 package book

创建 Book 类, 表示一本书

public class Book {
    private String name;//书名
    private String author;//作者
    private int price;//价格
    private String type;//类型
    private boolean isBorrowed;//是否借出

    public Book(String name, String author, int price, String type) {
        this.name = name;
        this.author = author;
        this.price = price;
        this.type = type;
    }

    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{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ((isBorrowed == true) ? "已经被借出" : "未被借出") +
                '}';
    }
}

创建 BookList 类, 用来保存 N 本书.

public class BookList {
    private Book[] books = new Book[10];
    private int usedSize;
    public BookList() {
        books[0] = new Book("三国演义","罗贯中",17,"小说");
        books[1] = new Book("西游记","吴承恩",47,"小说");
        books[2] = new Book("水浒传","施耐庵",37,"小说");
        this.usedSize = 3;
    }

    public int getUsedSize() {
        return usedSize;
    }

    public void setUsedSize(int usedSize) {
        this.usedSize = usedSize;
    }

    /**
     * 获取到pos位置的一本书
     * @param pos
     * @return
     */
    public Book getPos(int pos) {
        return this.books[pos];
    }

    /**
     * 设置pos下标为一本书->[添加一本书]
     * @param pos
     * @param book
     */
    public void setBook(int pos,Book book) {
        this.books[pos] = book;
    }

}

2. 创建操作相关的类

先创建 package Ioperation 接口便于拓展我们接下来的功能

public interface IOperation {
    void work(BookList bookList);
}

接下来创建一组操作类, 每个类对应一个用户的动作.

AddOperation

DelOperation

FindOperation

DisplayOperation

BorrowOperation

ReturnOperation

ExitOperation

先把空类创建好, 不着急实现细节.

抽象出 Operation 的好处: 让操作和操作之间低耦合, 让操作和用户之间低耦合.

将每一个功能单独拿出来在operation包中新建一个类，来面向对象编程具体实现如下：

3. 创建用户相关的类

先创建 package user

创建 User 类, 这是一个抽象类

// User 类是一个抽象类, 每个子类需要做两件事情
// 1. 初始化对应的操作数组
// 2. 实现 Menu 菜单
public abstract class User {
    protected String name;

    protected IOperation[] iOperations;

    public User(String name) {
        this.name = name;
    }
    public abstract int menu();

    public void doWork(int choice, BookList bookList) {
        iOperations[choice].work(bookList);
    }
}

创建普通用户类(NormalUser), 是 User 的子类.

public class NormalUser extends User{
    public NormalUser(String name) {
        super(name);
        this.iOperations = new IOperation[] {
                new ExitOperation(),
                new FindOperation(),
                new BorrowOperation(),
                new ReturnOperation()
        };
    }

    public int menu() {
        System.out.println("=========普通用户的菜单=========");
        System.out.println("hello"+this.name + "欢迎来到这里！");
        System.out.println("1. 查找图书");
        System.out.println("2. 借阅图书");
        System.out.println("3. 归还图书");
        System.out.println("0. 退出系统");
        System.out.println("=============================");
        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        return choice;
    }
}

创建管理员用户类(AdminUser)

public class AdminUser extends User{
    public AdminUser(String name) {
        super(name);
        this.iOperations = new IOperation[] {
                new ExitOperation(),
                new FindOperation(),
                new AddOperation(),
                new DelOperation(),
                new DisplayOperation()
        };
    }

    public int menu() {
        System.out.println("=========管理员菜单=========");
        System.out.println("hello"+this.name + "欢迎来到这里！");
        System.out.println("1. 查找图书");
        System.out.println("2. 新增图书");
        System.out.println("3. 删除图书");
        System.out.println("4. 显示所有图书");
        System.out.println("0. 退出系统");
        System.out.println("=============================");
        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        return choice;
    }
}

4. 进行整合

创建 Main 类和 main 方法, 搭建整体逻辑

public class Main {
    public static User login() {
        System.out.println("请输入你的姓名：");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        System.out.println("请输入你的身份：1->管理员 0->普通用户");
        int choice = scanner.nextInt();
        if(choice == 1) {
            return new AdminUser(name);
        } else {
            return new NormalUser(name);
        }

    }

    public static void main(String[] args) {
        BookList bookList = new BookList();
        User user = login();//向上转型
        while(true) {
            int choice = user.menu();//动态绑定 --> 多态
            //根据你的choice 调用合适的操作
            user.doWork(choice,bookList);
        }
    }
}

可以先测试下代码的基本框架是否存在问题

经检验代码没有问题，可以成功运行。

5. 实现具体的每个 Operation

接下来我们为大家讲解每一个功能的构建：

1、addOperation(增加图书功能)：

public class AddOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("新增图书！");
        System.out.println("请输入新增图书的名字：");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        System.out.println("请输入新增图书作者：");
        String author = scanner.nextLine();
        System.out.println("请输入新增图书类型：");
        String type = scanner.nextLine();
        System.out.println("请输入新增图书价格：");
        int price = scanner.nextInt();
        Book book = new Book(name,author,price,type);
        int size = bookList.getUsedSize();
        bookList.setBook(size,book);
        bookList.setUsedSize(size + 1);
        System.out.println("新增图书成功！");
    }

}

注意：我们增加完成后要记得给我们的图书数量size+1

2、BorrowOperation(借出图书功能)

public class BorrowOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("借出图书！");
        System.out.println("请输入你要借阅图书的名字：");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            if (name.equals(book.getName())) {
                book.setBorrowed(true);
                System.out.println("借阅成功！");
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有你要借阅的这本书！");
    }
}

3、DelOperation(删除图书功能)

public class DelOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("删除图书！");
        //1.根据书名找到书的位置 index
        System.out.println("请输入你要删除的图书的名字：");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedSize();
        int index = 0;//存储找到的下标
        int i = 0;
        for (; i < currentSize; i++) {
            Book book = bookList.getPos(i);
            if(book.getName().equals(name)) {
                index = i;
                break;
            }
        }
        if (i >= currentSize) {
            System.out.println("没有你要删除的这本书！");
            return;
        }
        //2.进行删除
        for (int j = index; j < currentSize - 1; j++) {
            //bookList[j] = bookList[j + 1]
            Book book = bookList.getPos(j+1);
            bookList.setBook(j,book);
        }
        bookList.setBook(currentSize,null);

        bookList.setUsedSize(currentSize - 1);
        System.out.println("删除成功！");
    }
}

4、DisplayOperation(打印图书功能)

public class DisplayOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("打印图书！");
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            System.out.println(book);
        }
    }
}

5、ExitOperation(退出图书管理系统)

public class ExitOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("退出系统！");
        System.exit(0);
    }
}

6、FindOperation(查找图书功能)

public class FindOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("查找图书！");
        System.out.println("请输入需要查找图书的名字：");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            if (book.getName().equals(name)) {
                System.out.println("找到了这本书，信息如下：");
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有找到这本书！");
    }
}

7、ReturnOperation(归还图书功能)

public class ReturnOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("归还图书！");
        System.out.println("请输入你要归还图书的名字：");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            if (name.equals(book.getName())) {
                book.setBorrowed(false);
                System.out.println("归还成功！");
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有你要归还的这本书！");

    }
}