图书管理小系统--整理复习javaSE语法

分析对象

在做一个项目的时候，先要搭建项目的架构，首先分析，图书管理系统，需要有书，人，操作等对象，我们将其分为

• book书：Book（图书）、BookList（存放图书的书架）
• user人：AdminUser（管理员）、NormalUser（普通用户）
• operation操作：增删查改
• Main类，程序的主入口
  

搭建框架

1、定义被继承对象User

在User中编写构造方法以及用户菜单

public abstract class User {
    
    

    public String name;

    //定义构造方法
    public User(String name) {
    
    
        this.name = name;
    }

	public abstract void menu();
}

2、编写用户类

对应的在AdminUser和NomalUser中继承User并编写构造方法，搭建不用用户菜单框架

public class NormalUser extends User{
    
    
    public NormalUser(String name) {
    
    
        super(name);
    }
    
    @Override
    public void menu() {
    
    
        System.out.println("普通用户的菜单");
    }
}

public class AdminUser extends User{
    
    
    public AdminUser(String name) {
    
    
        super(name);
    }
    
   	@Override
    public void menu() {
    
    
        System.out.println("管理员的菜单");
    }
}

3、编写Book类

提供属性，构造方法，get和set方法，以及打印的toString方法

package 图书管理.book;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: starry
 * Date: 2021 -01 -20
 * Time: 18:08
 */
public class Book {
    
    

    /**
     *图书的所有属性
     */
    private String name;    //图书名称
    private String author;  //作者
    private int price;      //价格
    private String type;    //类型
    private boolean status; //借出状态：默认false

    /**
     * 创建构造方法
     * @param name
     * @param author
     * @param price
     * @param type
     */
    public Book(String name, String author, int price, String type) {
    
    
        this.name = name;
        this.author = author;
        this.price = price;
        this.type = type;
    }

    /**
     * 既然封装了起来，编写get和set方法之后来调用Book中的属性
     * @return
     */
    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 isStatus() {
    
    
        return status;
    }

    public void setStatus(boolean status) {
    
    
        this.status = status;
    }

    /**
     * 提供打印所有属性的toString方法
     * @return
     */
    @Override
    public String toString() {
    
    
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ", status=" + status +
                '}';
    }
}

4、编写书架类

把书存入数组中，相当于放置在书架上

public class BookList {
    
    

    private Book[] books;   //图书对象，存放在顺序表中
    private int usedSize;

    public BookList(){
    
    
        this.books = new Book[10];
        books[0] = new Book("三国演义","罗贯中",55,"小说");
        books[1] = new Book("西游记","吴承恩",74,"小说");
        books[2] = new Book("水浒传","施耐庵",49,"小说");
        this.usedSize = 3;
    }

    //尾插法
    public void setBooks(int pos,Book book) {
    
    
        this.books[pos] = book;
    }

    public Book getBook(int pos) {
    
    
        return this.books[pos];
    }

    public int getUsedSize() {
    
    
        return usedSize;
    }

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

5、编写各个操作类

先不着急实现每个操作类的具体工作，先搭建框架

1. 先创建一个接口，让各种操作类实现这个接口

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

2. 添加数据类

public class AddOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("添加书籍");
    }
}

3. 借阅书籍类

public class BorrowOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("借阅书籍");
    }
}

4. 删除书籍

public class DelOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("删除书籍");
    }
}

5. 展示书籍

public class DisplayOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("展示书籍");
    }
}

6. 退出系统

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

7. 查找书籍

public class FindOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("查找书籍");
    }
}

8. 归还书籍

public class ReturnOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("归还书籍");
    }
}

Main程序入口

public class Main {
    
    

    public static User login() {
    
    
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入你的姓名");
        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) {
    
    
        //1.登录
        User user = login();    //向上转型
        user.menu();        //动态绑定
    }

}

现在我们已经实现了大概的程序框架，接下来就需要把每一部分完善了

整合框架

1、实现菜单

• User类

public abstract class User {
    
    

    public String name;
    //定义构造方法

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

    public abstract int menu();
}

• AdminUser类

public class AdminUser extends User{
    
    
    public AdminUser(String name) {
    
    
        super(name);
    }

    /**
     * 返回 你要执行的对应的操作
     * @return
     */
    @Override
    public int menu() {
    
    
        Scanner scanner = new Scanner(System.in);
        System.out.println("管理员的菜单");
        System.out.println("==============================");
        System.out.println("hello " + this.name + "欢迎来到图书系统");
        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.显示图书");
        System.out.println("0.退出系统");
        System.out.println("==============================");
        int choice = scanner.nextInt();
        return choice;
    }
}

• NormalUser类

public class NormalUser extends User{
    
    
    public NormalUser(String name) {
    
    
        super(name);
    }

    /**
     * 返回 你要执行的对应的操作
     * @return
     */
    @Override
    public int menu() {
    
    
        Scanner scanner = new Scanner(System.in);
        System.out.println("普通用户的菜单");
        System.out.println("==============================");
        System.out.println("hello " + this.name + "欢迎来到图书系统");
        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("==============================");
        int choice = scanner.nextInt();
        return choice;
    }
}

2、调用用户的功能方法

• User类

public abstract class User {
    
    

    public String name; //用户名
    public IOperation[] operations; //对应用户的操作数组

    //定义构造方法
    public User(String name) {
    
    
        this.name = name;
    }
    //用户菜单
    public abstract int menu();
    //调用对用操作的work方法
    public void doOperation(int choice, BookList bookList) {
    
    
        this.operations[choice].work(bookList);
    }

}

• AdminUser类

public class AdminUser extends User{
    
    
    public AdminUser(String name) {
    
    
        super(name);
        this.operations = new IOperation[] {
    
    
                new ExitOperation(),
                new FindOperation(),
                new AddOperation(),
                new DelOperation(),
                new DisplayOperation(),
        };  //调用不同功能
    }

    /**
     * 返回 你要执行的对应的操作
     * @return
     */
    @Override
    public int menu() {
    
    
        Scanner scanner = new Scanner(System.in);
        System.out.println("管理员的菜单");
        System.out.println("==============================");
        System.out.println("hello " + this.name + "欢迎来到图书系统");
        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.显示图书");
        System.out.println("0.退出系统");
        System.out.println("==============================");
        int choice = scanner.nextInt();
        return choice;
    }
}

• NormalUser类

public class NormalUser extends User{
    
    
    public NormalUser(String name) {
    
    
        super(name);
        this.operations = new IOperation[] {
    
    
                new ExitOperation(),
                new FindOperation(),
                new BorrowOperation(),
                new ReturnOperation(),
        };  //调用不同功能
    }

    /**
     * 返回 你要执行的对应的操作
     * @return
     */
    @Override
    public int menu() {
    
    
        Scanner scanner = new Scanner(System.in);
        System.out.println("普通用户的菜单");
        System.out.println("==============================");
        System.out.println("hello " + this.name + "欢迎来到图书系统");
        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("==============================");
        int choice = scanner.nextInt();
        return choice;
    }
}

• main函数

    public static void main(String[] args) {
    
    
        BookList bookList = new BookList();
        //1.登录
        User user = login();    //向上转型
        while (true) {
    
    
            //拿choice去调用对应类中的work方法
            int choice = user.menu();   //动态绑定
            user.doOperation(choice,bookList);
        }
    }

实现业务

1、添加图书

public class AddOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("添加书籍");
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入图书的名字");
        String name = scanner.nextLine();
        System.out.println("请输入图书的作者");
        String author = scanner.nextLine();
        System.out.println("请输入图书的价格");
        int price = scanner.nextInt();
        System.out.println("请输入图书的类型");
        String type = scanner.next();

        Book book = new Book(name,author,price,type);
        int currentSize = bookList.getUsedSize();
        //放在书架有的书后面
        bookList.setBooks(currentSize,book);

        bookList.setUsedSize(currentSize+1);
    }
}

2、查找图书

public class FindOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("查找书籍");
        Scanner scanner = new Scanner(System.in);
        System.out.println("输入要查找的书名");
        String name = scanner.nextLine();

        for(int i = 0; i < bookList.getUsedSize(); i++) {
    
    
            Book book = bookList.getBook(i);
            if(book.getName().equals(name)) {
    
    
                System.out.println("有这本书！");
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有这本书！");
    }
}

3、展示图书

public class DisplayOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("展示书籍");
        for(int i = 0; i < bookList.getUsedSize(); i++) {
    
    
            Book book = bookList.getBook(i);
            System.out.println(book);
        }
    }
}

4、借阅书籍

public class BorrowOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("借阅书籍");
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要借阅的书名");
        String name = scanner.nextLine();

        for(int i = 0; i < bookList.getUsedSize(); i++) {
    
    
            Book book = bookList.getBook(i);
            if (book.getName().equals(name)) {
    
    
                //说明有这本书
                //逻辑：把这本书的借阅状态修改为true
                book.setStatus(true);
                System.out.println("借阅成功！");
                System.out.println(book);
                return;
            }
        }
        System.out.println("借阅失败，没有你要借阅的图书");
    }
}

5、退出系统

public class ExitOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("退出系统");
        System.exit(1);
    }
}

6、删除书籍

public class DelOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("删除书籍");
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要删除的书名");
        String name = scanner.nextLine();

        int i;
        for(i = 0; i < bookList.getUsedSize(); i++) {
    
    
            Book book = bookList.getBook(i);
            if (book.getName().equals(name)) {
    
    
                break;
            }
        }

        if(i >= bookList.getUsedSize()) {
    
    
            System.out.println("没有你要删除的这本书！");
            return;
        }
        int pos = i;
        for(int j = pos; j < bookList.getUsedSize()-1; j++) {
    
    
            Book book = bookList.getBook(j+1);
            bookList.setBooks(j,book);
        }
        int currentSize = bookList.getUsedSize();
        bookList.setUsedSize(currentSize-1);
        System.out.println("删除书籍完毕！");
    }
}

7、归还书籍

public class ReturnOperation implements IOperation{
    
    
    @Override
    public void work(BookList bookList) {
    
    
        System.out.println("归还书籍");
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要归还的书名");
        String name = scanner.nextLine();

        for(int i = 0; i < bookList.getUsedSize(); i++) {
    
    
            Book book = bookList.getBook(i);
            if (book.getName().equals(name)) {
    
    
                //说明有这本书
                //逻辑：把这本书的借阅状态修改为false
                book.setStatus(false);
                System.out.println("归还成功！");
                System.out.println(book);
                return;
            }
        }
        System.out.println("归还失败，没有你要归还的图书");
    }

}