JavaSE——图书管理

2年前 (2022) 程序员胖胖胖虎阿
165 0 0

ced485cbb11e458d81a746890b32cf3f.gif

作者:敲代码の流川枫

博客主页:流川枫的博客

专栏:和我一起学java

语录:Stay hungry stay foolish

工欲善其事必先利其器,给大家介绍一款超牛的斩获大厂offer利器——牛客网

点击免费注册和我一起刷题吧  

文章目录

前言

book

Book

BookList

operation

IOperation

AddOperation

BorrowOperation

DelOperation

DisplayOperation

ExitOperation

FindOperation

ReturnOperation

user

User

AdminUser

NormalUser

Main


前言

以面向对象的思想找到并且抽象出图书管理所需要的对象,再分析这些类和对象应该具有哪些属性和方法,对象通过“属性”和“方法”来分别对应事物所具有的静态属性和动态属性,最后分析类和类之间具体有什么关系,通过各个对象间的交互,使用对象、类、继承、封装、接口等基本概念完成序设计 

抽象出来的对象有:书,书架,用户等,分别建立三个包管理JavaSE——图书管理 

book

Book

package book;
public class Book {
    //书名
    private String  name;
    //作者
    private String author;
    //价格
    private int price;
    //类型
    private String type;
    //状态
    private boolean isBorrow;
    public Book(String name, String author, int price, String type) {
        this.name = name;
        this.author = author;
        this.price = price;
        this.type = type;

    }
    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ((isBorrow==true)?"已借出":"未借出")+
                '}';
    }
    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 isBorrow() {
        return isBorrow;
    }

    public void setBorrow(boolean borrow) {
        isBorrow = borrow;
    }
}

BookList

先存储三本书:

JavaSE——图书管理

package book;

public class BookList {
    private Book[] books = new Book[10];
    private int usedSize;//存储当前书的个数

    public BookList() {

        books[0] = new Book("三国演义","罗贯中",90,"小说");
        books[1] = new Book("红楼梦","曹雪芹",80,"小说");
        books[2] = new Book("水浒传","施耐庵",70,"小说");

        this.usedSize = 3;
    }

    public int getUsedSize() {
        return usedSize;
    }

    public void setUsedSize(int usedSize) {
        this.usedSize = usedSize;
    }
    public Book getPos(int pos){
        return books[pos];

    }
    //存储一本书到指定的位置
    public void setBooks(Book book,int pos){
        books[pos] = book;
    }
}
//将对数组的操作写到一个接口中

operation

IOperation

package operation;

import book.BookList;

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

AddOperation

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class AddOperation implements IOperation{
    //添加图书
    public void work(BookList bookList){
        System.out.println("添加图书");

        System.out.println("请输入书名");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        System.out.println("请输入作者");
        String  author = scanner.nextLine();
        System.out.println("请输入价格");
        int price = scanner.nextInt();
        //读取回车
        scanner.nextLine();
        System.out.println("请输入类型");
        String type = scanner.nextLine();

        Book book =  new Book(name,author,price,type);
        //获取可以存放的位置
        int currentSize = bookList.getUsedSize();
        //放到指定位置
        bookList.setBooks(book,currentSize);
        //书的个数加一
        bookList.setUsedSize(currentSize+1);
    }
}

BorrowOperation

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class BorrowOperation implements IOperation{
    public void work(BookList bookList){
        System.out.println("借阅图书");
        System.out.println("请输入书名");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        //遍历是否有要借阅的书并记录下标
        int index = -1;
        int currentSize = bookList.getUsedSize();
        for (int i = 0; i < currentSize ; i++) {
            Book book = bookList.getPos(i);
            if(name.equals(book.getName())){
                if(book.isBorrow()){
                    System.out.println("已借出");
                }
                else{
                    book.setBorrow(true);
                    System.out.println("借阅成功");
                }
                return;
            }
        }
        System.out.println("没有要借阅的书");
    }
}

DelOperation

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class DelOperation implements IOperation{
    public void work(BookList bookList){
        System.out.println("删除图书");
        System.out.println("请输入书名");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();

        //遍历是否有要删除的书并记录下标
        int index = -1;
        int currentSize = bookList.getUsedSize();
        for (int i = 0; i < currentSize ; i++) {
            Book book = bookList.getPos(i);
            if(name.equals(book.getName())){
                index = i;
                break;
            }
        }
        if(index == -1){
            System.out.println("没有要删除的书");
            return ;
        }
        for (int i = index; i < currentSize-1 ; i++) {

            Book book = bookList.getPos(i+1);
            bookList.setBooks(book,i);
        }
        
        bookList.setBooks(null,currentSize-1);

        //重置有效长度
        bookList.setUsedSize(currentSize-1);
        System.out.println("删除成功");
    }
}

假设有四本书,那么i+1最大值就是3,即 i < currentSize-1才不会越界

JavaSE——图书管理

删除书之后要置空,否则可能会出现内存泄漏
一个对象没有人引用才会回收 

DisplayOperation

package operation;

import book.Book;
import book.BookList;

public class DisplayOperation implements IOperation{
    public void work(BookList bookList){
        System.out.println("显示图书");
        int currentSize = bookList.getUsedSize();
        for (int i = 0; i < currentSize ; i++) {
            Book book = bookList.getPos(i);
            System.out.println(book);
        }
    }
}

ExitOperation

package operation;

import book.BookList;
import com.sun.xml.internal.ws.api.model.wsdl.WSDLOutput;

public class ExitOperation implements IOperation{
    public void work(BookList bookList){
        System.out.println("退出系统");
        System.exit(0);
    }
}

FindOperation

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class FindOperation implements IOperation{
    //查找图书
    public void work(BookList bookList){
        System.out.println("查找图书");
        System.out.println("请输入书名:");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedSize();
        for (int i = 0; i < currentSize ; i++) {
            Book book = bookList.getPos(i);
            if(name.equals(book.getName())){
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有这本书");
    }
}

ReturnOperation

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class ReturnOperation implements IOperation{
    public void work(BookList bookList){

        System.out.println("归还图书");
        System.out.println("请输入书名");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();

        int index = -1;
        int currentSize = bookList.getUsedSize();
        for (int i = 0; i < currentSize ; i++) {
            Book book = bookList.getPos(i);
            if(name.equals(book.getName())){
                book.setBorrow(false);
                System.out.println("归还成功");
                return;
            }
        }
        System.out.println("没有要归还的书");
    }


}

user

User

package user;

import book.BookList;
import operation.IOperation;

public abstract class User {
    protected String name;
    //只是定义数组, 没有初始化,内存没有分配
    protected IOperation[] iOperations;
    public User(String name) {
        this.name = name;
    }
    public abstract int menu();
    public void doOperation (int choice, BookList bookList){
        iOperations[choice].work(bookList);

    }
}

JavaSE——图书管理

 需要写一个操作接口数组的方法doOperation()

AdminUser

package user;

import operation.*;

import java.util.Scanner;

//管理员
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("*************");
        System.out.println("hello"+name+"欢迎来到图书管理");
        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("*************");
        System.out.println("请输入你的操作:");

        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        return choice;

    }
}

NormalUser

package user;

import operation.*;

import java.util.Scanner;

//普通用户
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("*************");
        System.out.println("hello" + name + "欢迎来到图书管理");
        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("*************");
        System.out.println("请输入你的操作:");
        Scanner scanner = new Scanner(System.in);
        int choice = scanner.nextInt();
        return choice;
    }

}

Main

import book.BookList;
import user.AdminUser;
import user.NormalUser;
import user.User;

import java.util.Scanner;

public class Main {
    //利用向上转型确定是哪个对象
    public static  User login(){
        System.out.println("请输入你的姓名");
        Scanner scanner =  new Scanner(System.in);
        String userName = scanner.nextLine();
        System.out.println("请输入你的身份:1. 管理员  2. 用户");
        int choice = scanner.nextInt();
        if(choice==1){
           return new AdminUser(userName);
        }
        else{
            return new NormalUser(userName);
        }
    }

    public static void main(String[] args) {
        //先放三本书
        BookList bookList = new BookList();
        //登录
        User user =  login();
        while(true){
            int choice = user.menu();
            user.doOperation(choice,bookList);
        }
    }
}

JavaSE——图书管理

当引用的对象不同时,会打印不同的菜单

 

“ 本期的分享就到这里了, 记得给博主一个三连哈,你的支持是我创作的最大动力!

ced485cbb11e458d81a746890b32cf3f.gif

 

版权声明:程序员胖胖胖虎阿 发表于 2022年10月2日 上午2:08。
转载请注明:JavaSE——图书管理 | 胖虎的工具箱-编程导航

相关文章

暂无评论

暂无评论...