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;}@Overridepublic 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{@Overridepublic 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{@Overridepublic 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{@Overridepublic void work(BookList bookList) {System.out.println("删除图书！");//1.根据书名找到书的位置 indexSystem.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{@Overridepublic 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{@Overridepublic 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{@Overridepublic 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{@Overridepublic 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！");}
}

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！！！

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！😘