Java图书管理代码

╰半橙微兮° 2024-04-28 07:32 8阅读 0赞

#### 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：

![202212161603338.png][]

## 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.

![202212161606422.png][]

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：

![202212161606482.png][]

### 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

![202212161616312.png][]

经检验代码没有问题，可以成功运行。

![202212161631118.png][]

## 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！");
        }
    
    }

![202212161617863.png][]

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！");
        }
    }

![202212161617994.png][]

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！");
        }
    }

![202212161618605.png][]

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);
            }
        }
    }

![202212161619793.png][]

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);
        }
    }

![202212161619912.png][]

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！");
        }
    }

![202212161620273.png][]

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！");
    
        }
    }

![202212161620338.png][]

> 注意：在我们使用`next`和`nextLine`时要注意区分，如果使用`nextLine`要记得不要输入空白字符串，不然`nextLine`也会将空格字符直接录入。且`Scanner`最好随用随定义，不要在接口中定义再用`nextLine`，不然我们读取的第一个元素会自动变成空白！！！

![202212161620993.png][] ![202211250937967.png][]

*感谢各位读者的阅读，本文章有任何错误都可以在评论区发表你们的意见，我会对文章进行改正的。如果本文章对你有帮助请动一动你们敏捷的小手点一点赞，你的每一次鼓励都是作者创作的动力哦！😘*

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