图书管理，封装

Book实体类

package com.javasm.book.bean;

import lombok.*;

@Setter
@Getter
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Book {
    //编号
    private int bookId;
    //名称
    private String bookName;
    //作者
    private String bookAuthor;
    //价格
    private float bookPrice;
    //出版社
    private String bookPublish;

    //图书自增编号
    public static int identityID = 1000;

    /**
     * 有参构造
     *
     * @param bookName
     * @param bookAuthor
     * @param bookPrice
     * @param bookPublish
     */
    public Book(String bookName, String bookAuthor, float bookPrice, String bookPublish) {
        this.bookId = identityID++;
        this.bookName = bookName;
        this.bookAuthor = bookAuthor;
        this.bookPrice = bookPrice;
        this.bookPublish = bookPublish;
    }
}

BookAction：菜单列表，控制程序的走向

package com.javasm.book.action;

import com.javasm.book.bean.Book;
import com.javasm.book.service.BookService;

import java.util.Scanner;

public class BookAction {

    //扫描仪
    private static Scanner scanner = new Scanner(System.in);
    //业务对象
    private static BookService bookService = new BookService();
    //多本图书
    private static Book[] books = new Book[5];

    static {
        System.out.println("图书正在初始化~");
        books[0] = new Book("《西游记》", "吴承恩", 100, "清华大学出版社");
        books[1] = new Book("《西游记后传》", "钱雁秋", 50, "清华大学出版社");
        books[2] = new Book("《三国演义》", "罗贯中", 99, "清华大学出版社");
        books[3] = new Book("《水浒传》", "施耐庵", 88, "清华大学出版社");
        books[4] = new Book("《红楼梦》", "曹雪芹", 120, "清华大学出版社");
    }

    /**
     * 启动菜单
     */
    public static void startMenu() {
        boolean b = true;
        while (b) {
            System.out.println("***************欢迎你使用XXX图书管理系统****************");
            System.out.println("\t\t1、查看图书");
            System.out.println("\t\t2、添加图书");
            System.out.println("\t\t3、删除图书");
            System.out.println("\t\t4、修改图书");
            System.out.println("\t\t0、退出系统");
            System.out.println("请选择：");
            int choose = scanner.nextInt();

            switch (choose) {
                case 1:
                    bookService.showBook(books);
                    break;
                case 2:
                    books = bookService.addBook(books, scanner);
                    break;
                case 3:
                    books = bookService.deleteBook(books, scanner);
                    break;
                case 4:
                    bookService.updateBook(books, scanner);
                    break;
                case 0:
                    System.out.println("[谢谢使用，系统已退出！]");
                    b = false;
                    break;
            }
        }
    }
}

BookService：业务层

package com.javasm.book.service;

import com.javasm.book.bean.Book;

import java.util.Arrays;
import java.util.Scanner;

public class BookService {

    /**
     * 查看图书
     *
     * @param books
     */
    public void showBook(Book[] books) {
        System.out.println("图书管理系统>>>查看图书");
        for (Book book : books) {
            System.out.println(book);
        }
    }

    /**
     * 添加图书
     *
     * @param books
     * @param scanner
     * @return
     */
    public Book[] addBook(Book[] books, Scanner scanner) {
        System.out.println("图书管理系统>>>添加图书");
        //准备新书的基本信息
        Book book = new Book();
        book.setBookId(Book.identityID++); //自增id
        System.out.println("请输入图书的名称：");
        book.setBookName(scanner.next());
        System.out.println("请输入图书的作者：");
        book.setBookAuthor(scanner.next());
        System.out.println("请输入图书的价格：");
        book.setBookPrice(scanner.nextFloat());
        System.out.println("请输入图书的出版社：");
        book.setBookPublish(scanner.next());
        //先扩容
        books = Arrays.copyOf(books, books.length + 1);
        //将新书存入到最后一个索引位置
        books[books.length - 1] = book;
        System.out.println("[添加图书成功！]");
        return books;
    }

    /**
     * 删除图书
     *
     * @param books
     * @param scanner
     * @return
     */
    public Book[] deleteBook(Book[] books, Scanner scanner) {
        System.out.println("图书管理系统>>>删除图书");
        System.out.println("请输入你要删除的图书编号：");
        int inputId = scanner.nextInt();
        //根据图书编号查找对应的索引位置
        int index = getIndexById(books, inputId);
        //先判断
        if (index == -1) {
            System.out.println("[删除失败，该图书不存在！]");
            return books;
        }
        //循环覆盖
        for (int i = index; i < books.length - 1; i++) {
            //将后一个元素覆盖前一个
            books[i] = books[i + 1];
        }
        //缩容
        books = Arrays.copyOf(books, books.length - 1);
        System.out.println("[删除图书成功！]");
        return books;
    }

    /**
     * 修改图书
     *
     * @param books
     * @param scanner
     */
    public void updateBook(Book[] books, Scanner scanner) {
        System.out.println("图书管理系统>>>修改图书");
        System.out.println("请输入要修改的图书编号：");
        int inputId = scanner.nextInt();
        //根据图书编号查找对应的索引位置
        int index = getIndexById(books, inputId);
        //先判断
        if (index == -1) {
            System.out.println("[修改失败，该图书不存在！]");
            return;
        }
        //允许修改
        Book updateBook = books[index];  //对象是引用数据类型，引用数据类型传递的是内存地址！
 //       System.out.println("updateBook -->" + updateBook);
        //修改的就是原地址中的数据
        System.out.println("原图书名称：" + updateBook.getBookName() + "\t请输入修改之后的图书名称：");
        updateBook.setBookName(scanner.next());
        System.out.println("原图书作者：" + updateBook.getBookAuthor() + "\t请输入修改之后的图书作者：");
        updateBook.setBookAuthor(scanner.next());
        System.out.println("原图书价格：" + updateBook.getBookPrice() + "\t请输入修改之后的图书价格：");
        updateBook.setBookPrice(scanner.nextFloat());
        System.out.println("原图书出版社：" + updateBook.getBookPublish() + "\t请输入修改之后的图书出版社：");
        updateBook.setBookPublish(scanner.next());
        System.out.println("[修改图书成功！]");
    }

    /**
     * 根据编号查找图书对应的索引
     *
     * @param books
     * @param inputId
     * @return
     */
    private int getIndexById(Book[] books, int inputId) {
        int index = -1;
        for (int i = 0; i < books.length; i++) {
            if (inputId == books[i].getBookId()) {
                index = i;
            }
        }
        return index;
    }
}

BookTest：启动程序

package com.javasm.book.test;

import com.javasm.book.action.BookAction;

public class BookTest {
    /**
     * 程序的入口
     *
     * @param args
     */
    public static void main(String[] args) {
        //启动菜单
        BookAction.startMenu();
    }
}