前言

这篇博客是在学习了一部分Java基础语法之后的练习项目，通过这个小项目的练习，对Java中的类和对象，抽象类和接口，面向对象的继承、多态和封装、组合等进行熟悉理解；抽象出不同的对象，将对象进行合理的设计，完成对象之间的交互，面向对象进行编程。

1. 项目需求

图书管理系统，面向管理员和普通用户使用，对管理员的开放的功能有：添加图书，删除图书，查找图书，显示图书和退出程序等；对普通用户的开放的功能有：查找图书，借阅图书，归还图书和退出程序。

2. 实现思路

先抽象提取出不同的对象，首先想到的对象是用户和书，

用户可分为管理员和普通用户，将管理员和普通用户共有的属性设置为一个父类User，管理员和普通用户继承User，可以先将父类设置为普通类，在写码过程如果合适可以修改为抽象类；

系统对书进行管理，书本身就可以抽象为一个对象；对多本书进行操作管理，书架也可以抽象为一个对象；所以书和书架用两个类来实现，书架可以设计为一个数组；

这里系统对书进行管理，其实就是对书架对应数组进行操作，不同的操作可以通过一个标准去实现，也就是可以定义一个接口，每一个操作类去实现这个接口，完成向上转型，通过接口实现多态；

然后写代码的过程中思考完善各个对象的成员，最终实例化对象，通过不同对象之间的交互完成管理系统。

3. 代码实现

包的设计

book包

Book类

package book;
public class Book {
    private String name;//书名
    private String author;//书的作者
    private int price;//书的价格
    private String type;//书的类型
    private boolean borrowed;//是否被借出，默认false
    public Book(String name, String author, int 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 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 getBorrowed() {
        return borrowed;
    }
    public void setBorrowed(Boolean borrowed) {
        this.borrowed = borrowed;
    }
    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ", borrowed=" + ((borrowed==true) ? "已借出" : "未借出") +
                '}';
    }
}

BookList类

package book;
public class BookList {
    private Book[] books = new Book[100];
    private int usedsize;
    //书架当中默认有三本书
    public BookList() {
        this.books[0] = new Book("三国演义","罗贯中",66,"小说");
        this.books[1] = new Book("西游记","吴承恩",68,"小说");
        this.books[2] = new Book("红楼梦","曹雪芹",64,"小说");
        this.usedsize = 3;
    }
    public int getUsedsize() {
        return usedsize;
    }
    public void setUsedsize(int usedsize) {
        this.usedsize = usedsize;
    }
    public Book getBooks(int pos){
        return this.books[pos];
    }
    public void setBooks(Book book, int pos) {
        this.books[pos] = book;
    }
}

operations包

IOperation接口

package operations;
import book.BookList;
public interface IOperation {
    void work(BookList bookList);
}

AddOperation类

package operations;
import book.Book;
import book.BookList;
import java.util.Scanner;
public class AddOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("新增图书");
        //输入图书信息
        System.out.println("输入新增图书名称:");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        System.out.println("输入新增图书作者:");
        String author = scanner.nextLine();
        System.out.println("输入新增图书价格:");
        int price = scanner.nextInt();
        scanner.nextLine();
        System.out.println("输入新增图书类型:");
        String type = scanner.nextLine();
        Book book = new Book(name, author, price, type);
        //获取存书位置
        int currentSize = bookList.getUsedsize();
        //把书放到书架（数组）
        bookList.setBooks(book, currentSize);
        //书的总数加1
        bookList.setUsedsize(currentSize+1);
        System.out.println("添加成功！");
    }
}

BorrowOperation类

package operations;
import book.Book;
import book.BookList;
import java.util.Scanner;
public class BorrowOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("借阅图书");
        System.out.println("输入要借阅图书的名称:");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedsize();
        for (int i = 0; i < currentSize; i++) {
            Book book = bookList.getBooks(i);
            if (name.equals(book.getName())){
                if(book.getBorrowed()){
                    System.out.println("该书已经被借出！");
                    return;
                }else {
                    book.setBorrowed(true);
                    System.out.println("借阅成功！");
                    return;
                }
            }
        }
        System.out.println("没有找到你要借阅的书");
    }
}

DelOperation类

package operations;
import book.Book;
import book.BookList;
import java.util.Scanner;
public class DelOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("删除图书");
        System.out.println("输入要删除图书的名称:");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedsize();
        //找到并记录要删除书的下标
        int index = -1;
        for (int i = 0; i < currentSize; i++) {
            Book book = bookList.getBooks(i);
            if (name.equals(book.getName())){
                index = i;
                break;
            }
        }
        if(-1 == index) {
            System.out.println("没有找到要删除的这本书！");
        }else {
            for (int i = index; i < currentSize-1; i++) {
                Book book = bookList.getBooks(i+1);
                bookList.setBooks(book, i);
            }
            //每次删除，都要将原来最后一本书位置的引用置空
            bookList.setBooks(null,currentSize-1);
            bookList.setUsedsize(currentSize-1);
            System.out.println("删除成功");
        }
    }
}

DisplayOperation类

package operations;
import book.Book;
import book.BookList;
import java.util.Scanner;
public class DisplayOperation implements IOperation{
    @Override
    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.getBooks(i);
            System.out.println(book);
        }
    }
}

ExitOperation类

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

FindOperation类

import book.Book;
import book.BookList;
import java.util.Scanner;
public class FindOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("查找图书");
        System.out.println("输入要查找图书的名称:");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedsize();
        for (int i = 0; i < currentSize; i++) {
            Book book = bookList.getBooks(i);
            if (name.equals(book.getName())){
                System.out.println("找到了，该书信息如下:");
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有找到这本书！");
    }
}

ReturnOperation类

package operations;
import book.Book;
import book.BookList;
import java.util.Scanner;
public class ReturnOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("归还图书");
        System.out.println("输入要归还图书的名称:");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedsize();
        for (int i = 0; i < currentSize; i++) {
            Book book = bookList.getBooks(i);
            if (name.equals(book.getName())){
                if(book.getBorrowed()){
                    book.setBorrowed(false);
                    System.out.println("归还成功！");
                    return;
                }else {
                    System.out.println("该书未借出！");
                    return;
                }
            }
        }
        System.out.println("没有找到你要归还的书");
    }
}

user包

User类

public abstract class User {
    protected String name;
    protected IOperation[] iOperation;
    public User(String name) {
        this.name = name;
    }
    public abstract int menu();
    public void doOperation(int choice, BookList bookList){
        iOperation[choice].work(bookList);
    }
}

AdminUser类

package user;
import operations.*;
import java.util.Scanner;
public class AdminUser extends User{
    public AdminUser(String name) {
        super(name);
        this.iOperation = new IOperation[]{
                new ExitOperation(),
                new FindOperation(),
                new AddOperation(),
                new DelOperation(),
                new DisplayOperation()
        };
    }
    @Override
    public int menu() {
        System.out.println("---------------------------------");
        System.out.println("Hello 管理员:>"+""+name+" 欢迎来到图书管理系统！");
        System.out.println("      1.查找图书  2.新增图书");
        System.out.println("      3.删除图书  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类

package user;
import operations.*;
import java.util.Scanner;
public class NormalUser extends User{
    public NormalUser(String name) {
        super(name);
        this.iOperation = new IOperation[]{
                new ExitOperation(),
                new FindOperation(),
                new BorrowOperation(),
                new ReturnOperation()
        };
    }
    @Override
    public int menu() {
        System.out.println("---------------------------------");
        System.out.println("Hello 用户:>"+name+" 欢迎来到图书管理系统！");
        System.out.println("      1.查找图书  2.借阅图书");
        System.out.println("      3.归还图书  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类

import book.BookList;
import user.AdminUser;
import user.NormalUser;
import user.User;
import java.util.Scanner;
public class Main {
    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("请确认你的身份:> |1->管理员|0->普通用户|");
        int choice = scanner.nextInt();
        if(1==choice){
            return new AdminUser(userName);
        }else{
            return new NormalUser(userName);
        }
    }
    public static void main(String[] args) {
        //准备数据
        BookList bookList = new BookList();
        //登录
        User user = login();
        while (true) {
            int choice = user.menu();
            user.doOperation(choice, bookList);
        }
    }
}

【Java】SE练习项目 —》图书管理系统

前言

1. 项目需求

2. 实现思路

3. 代码实现

包的设计

book包

Book类

BookList类

operations包

IOperation接口

AddOperation类

BorrowOperation类

DelOperation类

DisplayOperation类

ExitOperation类

FindOperation类

ReturnOperation类

user包

User类

AdminUser类

NormalUser类

Main类

4. 实现效果

管理员

普通用户

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【Java】SE练习项目 —》图书管理系统

前言

1. 项目需求

2. 实现思路

3. 代码实现

包的设计

book包

Book类

BookList类

operations包

IOperation接口

AddOperation类

BorrowOperation类

DelOperation类

DisplayOperation类

ExitOperation类

FindOperation类

ReturnOperation类

user包

User类

AdminUser类

NormalUser类

Main类

4. 实现效果

管理员

普通用户

热门文章

最新文章

相关课程

相关电子书

相关实验场景