详解：

BookList类：

InOperation接口

User类（父类）和 Main类（这俩要一起看）

完整代码

book包

Book类

BookList类

operation包

AddBook类

BorrowBook类

DeleteBook类

FindBook类

PrintBook类

ReturnBook类

Exit类

InOperation接口

user包

Domestic类

Administrator类

User类

Main类

详解：

按照上图逻辑来写，因为要运行，所以要有个main函数

接下来我们来串联整个思路

接下来细说BookList类，InOperation接口和User类

BookList类：

1.先创建一个Book类类型的数组（private 封装）

2.再创建个书的个数的变量（private 封装），然后创建构造方法,初始化成员（图书）（实例化BookList时直接就运行书架里的内容）（实例化一个Book对象，有参类型，所以Book类哪里要先创建有参的构造方法）

既然封装了就要有Getter和Setter (下面系统自动生成步骤)

当然自动生成的和我们要的还是有点差别的，我们要稍微改动一下

InOperation接口

因为每一个操作功能都要有对应的工作，所以干脆创建个接口，对代码更好的规范

User类（父类）和 Main类（这俩要一起看）

各个包类都创建好了，但是他们如果串联运行呢，要有main才能运行起来，怎么搞，往下看

（上面可能看不太清，可以对着下面看一下，或者对着代码看）

剩下的方法实现起来都蛮简单的，对比着代码看看就能懂，不多说了 😊😊

完整代码

book包

Book类

package book;

public class Book {
    private String name;
    private String author;
    private double price;
    private String type;
    private boolean borrowed;//默认false
    public Book(String name, String author, double 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 double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public boolean isBorrowed() {
        return borrowed;
    }

    public void setBorrowed(boolean borrowed) {
        this.borrowed = borrowed;//借出true
                                 //未被借出false
    }

    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ((borrowed == false)?"   未被借出":"   已借出") +
                '}';
    }
}

BookList类

package book;

public class BookList {
    //创建数组存放书
    private Book[] books = new Book[10];



    private int book_size;//书的个数
    //构造方法,初始化成员（图书）（示例化BookList时直接就运行书架里的内容）
    public BookList() {
        this.books[0] = new Book("三国演义", "罗贯中", 23.1, "小说");//实例化一个Book对象，有参类型，所以Book类哪里要先创建有参的构造方法
        this.books[1] = new Book("西游记", "吴承恩", 45.1, "小说");
        this.books[2] = new Book("红楼梦", "曹雪芹", 33.2, "小说");
        this.books[3] = new Book("水浒传", "施耐庵", 23.2, "小说");
        this.book_size = 4;
    }

    public Book getBooks(int pos) {
        return books[pos];
    }

    public void setBooks(int pos, Book book) {
        this.books[pos] = book;//新增图书需要
    }

    public int getBook_size() {
        return book_size;
    }

    public void setBook_size(int book_size) {
        this.book_size = book_size;
    }

}

operation包

AddBook类

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class AddBook implements InOperation{

    @Override
    public void work(BookList bookList) {
        System.out.println("新增图书");
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入图书名字：>");
        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();
        scanner.nextLine();
        System.out.println("请输入图书的类型：>");
        String type = scanner.nextLine();

        Book book = new Book(name, author, price, type);//实例化Book对象,存新增的书
        int currentSize = bookList.getBook_size();//当前剩下的书的数量
        for(int i = 0; i < currentSize; i++){
            Book book1 = bookList.getBooks(i);
            if(book1.getName().equals(name)){
                System.out.println("书架已有此书，不必添加");
            }
            return;
        }
        bookList.setBooks(currentSize, book);
        bookList.setBook_size(currentSize + 1);
        System.out.println("添加成功！！！");
    }
}

BorrowBook类

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class BorrowBook implements InOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("借阅图书");
        System.out.println("请输入所借图书名字");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getBook_size();

        for(int i = 0; i < currentSize; i++){
            Book book = bookList.getBooks(i);
            if(book.getName().equals(name)){
                if(book.isBorrowed() == false) {
                    book.setBorrowed(true);
                    System.out.println("存在该书，欢迎借阅");
                }else {
                    System.out.println("该书不存在，对不起");
                }
                return;
            }

        }
    }
}

DeleteBook类

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class DeleteBook implements InOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("删除图书");
        System.out.println("请输入你要删除的图书名字：>");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getBook_size();
        if(currentSize == 0){
            System.out.println("书架为空");
        }

        int flag = -1;
        for(int i = 0; i < currentSize; i++){
            Book book = bookList.getBooks(i);
            if(book.getName().equals(name)){
                flag = i;
                break;
            }
        }
        if(flag == -1){
            System.out.println("该书不存在");
            return;
        }

        //虽然这样访问不到最后一本书，但是书的数量减一了，这样就自然没了最后一本书
        for(int i = flag; i < currentSize - 1; i++) {
            bookList.setBooks(flag, bookList.getBooks(i + 1));
        }
        bookList.setBook_size(currentSize - 1);
        System.out.println("删除成功");
    }
}

FindBook类

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class FindBook implements InOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("寻找图书");
        System.out.println("输入图书名字;>");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();

        int currentSize = bookList.getBook_size();
        int index = -1;
        for(int i = 0; i < currentSize; i++){
            Book book = bookList.getBooks(i);
            if(book.getName().equals(name)) {
               index = i;
            }
        }
        if(index == -1){
            System.out.println("该书不存在");
            return;
        }
        Book book = bookList.getBooks(index);
        System.out.println(book);
    }
}

PrintBook类

package operation;

import book.Book;
import book.BookList;

public class PrintBook implements InOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("显示全部图书");
        int currentSize = bookList.getBook_size();
        for(int i = 0; i < currentSize; i++){
            Book book = bookList.getBooks(i);
            System.out.println(book);
        }
    }
}

ReturnBook类

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class ReturnBook implements InOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("归还图书");
        System.out.println("请输入图书名字");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getBook_size();
        for (int i = 0; i < currentSize; i++){
            Book book = bookList.getBooks(i);
            if(book.getName().equals(name)){
                book.setBorrowed(false);
                System.out.println("归还成功");
                return;
            }
        }
        System.out.println("没这本书");
    }
}

Exit类

package operation;

import book.BookList;

public class Exit implements InOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("退出系统");
        int currentSize = bookList.getBook_size();
        for(int i = 0; i < currentSize; i++){
            bookList.setBooks(i,null);
        }
        bookList.setBook_size(0);
        System.exit(0);
    }
}

InOperation接口

package operation;

import book.BookList;

public interface InOperation {
      void work(BookList bookList);//因为这些操作都是在书架上，所以传参位BookList类型
}

user包

Domestic类

package user;

import operation.*;

import java.util.Scanner;

import book.BookList;

public class Domestic extends User{
    public Domestic(String name) {
        super(name);
        this.inOperations = new InOperation[]{
                new Exit(),
                new BorrowBook(),
                new ReturnBook(),
                new FindBook()//记得都要实例化对象才能用，因为他们都是类
        };
    }


    @Override
    public int menu() {
        System.out.println("**********当当当！！！欢迎来到普通用户的菜单~~ *********");
        System.out.println("1.借阅图书       2.归还图书 ");
        System.out.println("        3.查找图书       ");
        System.out.println("        0.退出系统         ");
        System.out.println("请输入你想要进行的操作所对应的数字~~");
        Scanner s = new Scanner(System.in);
        int input = s.nextInt();
        return input;
    }
}

Administrator类

package user;
import operation.*;

import java.util.Scanner;
public class Administrator extends User{
    public Administrator(String name) {
        super(name);
        this.inOperations = new InOperation[]{
          new Exit(),
          new AddBook(),
          new DeleteBook(),
          new FindBook(),
          new PrintBook()
        };
    }

    @Override
    public int menu() {
        System.out.println("**********当当当！！！欢迎来到管理员的菜单~~ *********");
        System.out.println("1.新增图书       2.删除图书 ");
        System.out.println("3.查找图书       4.显示全部图书 ");
        System.out.println("        0.退出系统         ");
        System.out.println("请输入你想要进行的操作所对应的数字~~");
        Scanner s = new Scanner(System.in);
        int input = s.nextInt();
        return input;
    }
}

User类

package user;

import book.BookList;
import operation.InOperation;

public abstract class User {
    private String name;
    public InOperation[] inOperations;//用public哟，以便其他地方使用

    public User(String name) {
        this.name = name;
    }
    public abstract int menu();
    public void doOperation(int choice, BookList bookList){
        inOperations[choice].work(bookList);
        //找到了对应的操作功能    调用相应的work方法
    }
}

Main类

import book.BookList;
import user.Administrator;
import user.Domestic;
import user.User;

import java.util.Scanner;
public class Main {
    public static User login(){
        System.out.println("********** ~~欢迎来到图书管理系统~~ **********");
        System.out.println("请登录/注册");
        System.out.println("请选择你的身份   1 ---> 管理员     0 ---> 普通用户");
        Scanner s = new Scanner(System.in);
        int choice = s.nextInt();
        System.out.println("请输入你的名字");

        String name = s.next();
        if(choice == 1){
            return new Administrator(name);
        }else {
            return new Domestic(name);
        }
    }

    public static void main(String[] args) {
        BookList bookList = new BookList();//实例化对象
        User user = login();//这个确定身份（管理员或者普通用户）
        while(true){
            int choice = user.menu();//这个确定进行什么操作
            user.doOperation(choice, bookList);
        }
    }
}