Java——面向对象练习（图书管理系统的实现）

2021-05-30 23:44 442人阅读评论(0)

Java——面向对象练习（图书管理系统的实现）

在前面一段时间里，学习了 Java 面向对象的相关内容：包的使用、继承、多态、抽象类、接口等知识，现在为了巩固我们所学习的知识，接下来我们将从零到有实现一个简单版的图书管理系统的代码实现。

一、实现效果展示

（1）功能简介

（2）登陆界面

（3）菜单界面

（4）功能展示

1.显示图书

2.新增图书

3.删除图书

4.查找图书

5.借阅图书

6.归还图书

二、具体代码实现

1.类的设计

我们通过这个管理系统的功能简介等，可以知道我们需要设计的几个类

（1）创建图书相关的类

先创建 package book

创建 Book 类, 表示一本书

package book;

public class Book {
   

    private String name;
    private String author;
    private int price;
    private String type;
    private boolean isBorrowed;

    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;
    }

    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 + '\'' +
                ", isBorrowed=" + isBorrowed +
                '}';
    }
}

这个书的类中，有书的各种属性：书名、作者、价格、类别、借阅情况，同时将这些属性都封装起来。

创建 BookList 类, 用来保存 N 本书.

package book;

public class BookList {
   

    private Book[] books = new Book[100];
    private int usedSize;


    public BookList(){
   

        //默认有四本书

        books[0] = new Book("西游记","吴承恩",10,"小说" );
        books[1] = new Book("水浒传","施耐庵",20,"小说" );
        books[2] = new Book("红楼梦","曹雪芹",10,"小说" );
        books[3] = new Book("三国演义","罗贯中",10,"小说" );
        this.usedSize  = 4;
    }

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

    public void setBooks(int pos,Book book) {
   
        //默认放到顺序表的最后
        this.books[pos] = book;
    }

    public int getUsedSize() {
   
        return usedSize;
    }

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

用顺序表的方式存储书籍，且在书架中默认有四本书，设置一个现有书籍数量 usedSize的属性，在构造方法中存储四本书，usedSize = 4.

（2）创建操作相关的类

先创建 package operation

接下来创建一组操作类, 每个类对应一个用户的动作.

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.

1.接口的实现

package operation;

import book.BookList;

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

2.新增书籍

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class AddOperation implements IOperation {
   
    @Override
    public void work(BookList bookList){
   
        Scanner scanner  = new Scanner(System.in);
        System.out.println("请输入书名：");
        String name = scanner.nextLine();
        System.out.println("请输入作者：");
        String author = scanner.nextLine();
        System.out.println("请输入类别：");
        String type = scanner.nextLine();
        System.out.println("请输入价格：");
        int price  = scanner.nextInt();

        for (int i = 0; i <bookList.getUsedSize() ; i++) {
   
            Book book = bookList.getBooks(i);
            if(name.equals(book.getName())){
   
                System.out.println("书架存在这本书，不能重复添加！");
                return;
            }
        }

        int currentSize = bookList.getUsedSize();

        Book book = new Book(name,author,price,type);

        bookList.setBooks(currentSize,book);

        bookList.setUsedSize(currentSize+1);

        System.out.println("增加成功！");
    }
}

3.删除书籍

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;


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("请输入要删除的图书的名字:");
        String name = scanner.nextLine();

        int currentSize = bookList.getUsedSize();

        int index = -1;

        for (int i = 0; i < currentSize; i++) {
   

            Book book = bookList.getBooks(i);

            if(name.equals(book.getName())) {
   
                //找到了这本书
                index = i;
            }

        }
        if(index == -1) {
   
            System.out.println("没有你要删除的书！");
            return;
        }

        for (int i = index; i < currentSize-1; i++) {
   
            Book book1 = bookList.getBooks(i+1);
            bookList.setBooks(i,book1);
            //bookList[i] = bookList[i+1];
        }

        //防止内存泄漏
        bookList.setBooks(currentSize-1,null);
        //控制usedSize
        bookList.setUsedSize(currentSize-1);

        System.out.println("删除成功！");
    }
}

4.展示书籍

package operation;

import book.Book;
import book.BookList;

public class DisplayOperation implements IOperation{
   
    @Override
    public void work(BookList bookList) {
   

        for (int i = 0; i <bookList.getUsedSize() ; i++) {
   
            Book book = bookList.getBooks(i);
            System.out.println(book);
            }
        }
    }

5.查找书籍

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

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

        for (int i = 0; i <booklist.getUsedSize() ; i++) {
   
            Book book = booklist.getBooks(i);
            if(name.equals(book.getName())){
   
                System.out.println("找到此书入下：");
                System.out.println(book);
                return ;
            }
        }

        System.out.println("没有这本书！");
    }
}

6.借阅书籍

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

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


        for (int i = 0; i <bookList.getUsedSize(); i++) {
   

            Book book = bookList.getBooks(i);

            if(name.equals(book.getName()) && book.isBorrowed()==false) {
   
                //找到了就借阅
              book.setBorrowed(true);
              return ;
            }
        }
        System.out.println("借阅失败，没有此书 ，或此书已被借出");
    }
}

7.归还书籍

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

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


        for (int i = 0; i <bookList.getUsedSize(); i++) {
   

            Book book = bookList.getBooks(i);

            if(name.equals(book.getName())) {
   
                //找到了就归还
                book.setBorrowed(false);
                System.out.println("归还成功！");
                return ;
            }
        }
        System.out.println("归还失败，没有此书！");
    }
}

8.退出系统

package operation;


import book.BookList;

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

（3）创建用户相关的类

1.父类用户 user 的实现

package users;

import book.BookList;
import operation.*;

public abstract class User {
   

    protected String name;
    protected IOperation[] iOperations ;

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

    public abstract int menu();
    public void doOperation(int choice, BookList bookList){
   
         this.iOperations[choice].work(bookList);
    }
}

2.管理员用户的实现

package users;

import book.BookList;
import operation.*;

import java.util.Scanner;

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(){
   
        Scanner scanner = new Scanner(System.in);
        System.out.println("hello"+this.name+" "+"欢迎来到图书小练习!");
        System.out.println("=========管理员菜单=========");
        System.out.println("=========0.退出系统=========");
        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=========");

        int choice = scanner.nextInt();
        return choice;
    }

    @Override
    public void doOperation(int choice, BookList bookList) {
   
        super.doOperation(choice, bookList);
    }
}

3.普通用户类的实现

import operation.*;

import java.util.Scanner;

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(){
   
            Scanner scanner = new Scanner(System.in);
            System.out.println("hello"+this.name+" "+"欢迎来到图书小练习!");
            System.out.println("========普通用户菜单=========");
            System.out.println("=========0.退出系统=========");
            System.out.println("=========1.查找图书=========");
            System.out.println("=========2.借阅图书=========");
            System.out.println("=========3.归还图书=========");

            int choice = scanner.nextInt();
            return choice;
        }

    @Override
    public void doOperation(int choice, BookList bookList) {
   
        super.doOperation(choice, bookList);
    }
}

Main 函数的设计

import book.Book;
import book.BookList;
import users.AdminUser;
import users.NormalUser;
import users.User;

import java.util.Scanner;

public class Main {
   

    public static User login(){
   
        System.out.println("请输入姓名：");
        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 who  = scanner.nextInt();
        if(who == 1){
   
            return new AdminUser(name);
        }else{
   
            return new NormalUser(name);
        }

    }

    public static void main(String[] args) {
   
        BookList bookList = new BookList();
       User user = login();

      while(true) {
   
          // 根据菜单的选项 调用合适的方法
          int choice = user.menu();
          user.doOperation(choice, bookList);
      }

    }

}

本次练习的目的只是为了熟悉 Java面向对象的特性,在实现具体功能的业务逻辑时并没有那么严谨,希望大家多多指正!

好了今天的分享到这里就结束了,感谢大家的观看.

感谢关注!!

完!

转载：https://blog.csdn.net/rain67/article/details/117253336

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