简介

哈喽哈喽大家好啊，之前作者也是讲了Java不少的知识点了，为了巩固之前的知识点再为了让我们深入Java面向对象这一基本特性，就让我们完成一个图书管理系统的小项目吧。

项目简介：通过管理员和普通用户的两种操作界面，利用其中的方法以及对象之间的交互，来实现对图书的管理。

源码

book包

主要包含book对象和book List对象以及Main方法

Book类

描述书的有关信息，构造方法和各种getter，setter方法

public class Book {
    //书的属性：名字，作者，价格，类型，借出情况
    private String name;
    private String author;
    private int price;
    private String type;
    private boolean borrowed;

    public Book(){

    }

    public Book(String name, String author, int price, String type) {
        this.name = name;
        this.author = author;
        this.price = price;
        this.type = type;
    }

    /**
     * 获取
     * @return name
     */
    public String getName() {
        return name;
    }

    /**
     * 设置
     * @param name
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * 获取
     * @return author
     */
    public String getAuthor() {
        return author;
    }

    /**
     * 设置
     * @param author
     */
    public void setAuthor(String author) {
        this.author = author;
    }

    /**
     * 获取
     * @return price
     */
    public int getPrice() {
        return price;
    }

    /**
     * 设置
     * @param price
     */
    public void setPrice(int price) {
        this.price = price;
    }

    /**
     * 获取
     * @return type
     */
    public String getType() {
        return type;
    }

    /**
     * 设置
     * @param type
     */
    public void setType(String type) {
        this.type = type;
    }

    /**
     * 获取
     * @return borrowed
     */
    public boolean isBorrowed() {
        return borrowed;
    }

    /**
     * 设置
     * @param borrowed
     */
    public void setBorrowed(boolean borrowed) {
        this.borrowed = borrowed;
    }

    public String toString() {
        return "Book{name = " + name + ", author = " + author + ", price = " + price + ", type = " + type + "," +/*", borrowed = " + borrowed*/
                ((isBorrowed() == true) ? " 已被借出" : " 未被借出")+ "}";
    }
}

BookList

作为书架，利用数组存放书籍.

public class BookList {
    //定义数组成员表示存放书的数组
    public Book[] books;
    //表示书架上存放书的数量
    private int useSize;
    //设置最大容量
    private static final int DEFAULT_CAPACITY = 10;

    public BookList() {
        this.books = new Book[DEFAULT_CAPACITY];
        //先提前放好三本书
        this.books[0] = new Book("三国演义", "罗贯中", 10, "小说");
        this.books[1] = new Book("西游记", "吴承恩", 9, "小说");
        this.books[2] = new Book("红楼梦", "曹雪芹", 19, "小说");

        this.useSize = 3;
    }

    //书架上书的数量的getter和setter方法
    public int getUseSize() {
        return useSize;
    }

    public void setUseSize(int useSize) {
        this.useSize = useSize;
    }

    //通过下标获取对应书籍的getter方法
    public Book getBook(int pos) {
        return books[pos];
    }

    //通过下标和传入的书对象设置对应书籍的setter方法
    public void setBooks(int pos, Book book) {
        books[pos] = book;
    }

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

Main方法

主要的操作逻辑

import user.AdminUser;
import user.NormalUser;
import user.User;

import java.util.Scanner;

public class Main {
    //可以利用返回值的向上转型 达到发挥的一致性
    public static User Login() {
        System.out.println("请输入你的姓名：");
        Scanner sc = new Scanner(System.in);
        String name = sc.nextLine();
        System.out.println("请输入你的身份：1.管理员 2.普通用户 ->");
        int choice = sc.nextInt();
        if (choice == 1) {
            //管理员
            return new AdminUser(name);
        } else if (choice == 2) {
            //普通用户
            return new NormalUser(name);
        }
        return null;
    }

    public static void main(String[] args) {
        BookList booklist = new BookList();
        //user指向哪个对象 就看返回值
        User user = Login();
        while(true) {
            int choice = user.menu();
            //System.out.println("choice:" + choice);

            //根据choice来决定调用哪个方法
            user.doOperation(choice, booklist);
        }
    }
}

user包

主要包含user以及相关对象

父类User

包含基本属性：姓名，menu（菜单）方法的声明，doOperation（执行方法操作）方法的声明。

import book.BookList;
import operation.IOPeration;

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) {
        ioperations[choice].work(booklist);bao
    }
}

子类AdminUser

包含管理员使用方法的数组和管理员菜单。

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 ShowOperation()};
    }

    //管理员专用菜单
    public int menu() {
        System.out.println("*************管理员界面*************");
        System.out.println("hello " + this.name +"欢迎来到管理员菜单！");
        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 sc = new Scanner(System.in);
        int choice = sc.nextInt();
        return choice;
    }
}

子类NormalUser

包含普通用户使用方法的数组和普通用户菜单。

package user;
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 ReturnOperatoin(),
        };
    }

    //普通用户用菜单
    public int menu() {
        System.out.println("*************普通用户界面*************");
        System.out.println("hello " + this.name +"欢迎来到普通用户菜单！");
        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 sc = new Scanner(System.in);
        int choice = sc.nextInt();
        return choice;
    }
}

Operation包

主要包含各种操作方法

IOPeration接口

后续使用所有方法继承这个接口，对bookList对象进行相关工作。

package operation;

import book.BookList;

public interface IOPeration {
    void work(BookList booklist);
}

AddOperation方法

添加图书的方法

package operation;

import book.BookList;
import book.Book;

import java.util.Scanner;

public class AddOperation implements IOPeration{
    @Override
    public void work(BookList booklist) {
        System.out.println("增加书籍");
        Scanner sc = new Scanner(System.in);
        int currentSize = booklist.getUseSize();
        //用户输入书籍信息
        System.out.println("请输入书籍的名称：");
        String name =sc.nextLine();
        System.out.println("请输入书籍的作者：");
        String author = sc.nextLine();
        System.out.println("请输入书籍的类型：");
        String type = sc.nextLine();
        //注意：这里将回车放到最后，如果放在前面，下一个nextLine()会读入回车
        System.out.println("请输入书籍的价格：");
        int price = sc.nextInt();

        //创建一个新的book对象导入刚才的信息
        Book book = new Book(name, author, price, type);
        //检查书架当中是否有这本书
        for (int i = 0; i < currentSize; i++) {
            Book book1 = booklist.getBook(i);
            //判断书架中的书与新导入书的引用是否相等
            if(book1 == book) {
                System.out.println("书架上有这本书，添加失败");
                return;
            }
        }
        //判断添入书是否超出书架最大容量，未超出则添入书籍
        if(currentSize == booklist.getBooks().length) {
            System.out.println("书架已满，添加失败");
        } else {
            //在书架中添入书籍
            booklist.setBooks(currentSize, book);
            //存放书的数量+1
            booklist.setUseSize(currentSize + 1);
            System.out.println("添加成功");
        }
    }

}

FindOperation方法

寻找图书的方法

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("寻找书籍");
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入您要寻找的书籍");
        String name = sc.nextLine();
        int currentSize = booklist.getUseSize();
        for (int i = 0; i < currentSize; i++) {
            Book book = booklist.getBook(i);
            if(book.getName().equals(name)) {
                System.out.println("找到了，是这本书：");
                System.out.println(book);
                return;
            }
        }
        System.out.println("没有找到这本书");
    }
}

DelOperation方法

删除图书所使用的方法

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");
        //1.找到有没有这本书
        System.out.println("请输入要删除书的名字");
        Scanner sc = new Scanner(System.in);
        String name = sc.nextLine();
        int currentSize = bookList.getUseSize();
        for (int i = 0; i < currentSize; i++) {
            Book book = bookList.getBook(i);
            if (book.getName().equals(name)) {
                //2.如果有，从这本书后面开始，从前往后向前覆盖
                for (; i < currentSize; i++) {
                    Book book1 = bookList.getBook(i + 1);
                    bookList.setBooks(i, book1);
                }
                //3.将最后一本书置为空
                bookList.setBooks(currentSize - 1, null);
                //数组最大容量减少
                bookList.setUseSize(currentSize - 1);
                System.out.println("删除成功！");
                return;
            }
        }
        //未删除成功的情况
        System.out.println("该书不存在，删除失败");
        return;
    }
}

ShowOperation方法

显示所有图书的方法

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");
        //1.找到有没有这本书
        System.out.println("请输入要删除书的名字");
        Scanner sc = new Scanner(System.in);
        String name = sc.nextLine();
        int currentSize = bookList.getUseSize();
        for (int i = 0; i < currentSize; i++) {
            Book book = bookList.getBook(i);
            if (book.getName().equals(name)) {
                //2.如果有，从这本书后面开始，从前往后向前覆盖
                for (; i < currentSize; i++) {
                    Book book1 = bookList.getBook(i + 1);
                    bookList.setBooks(i, book1);
                }
                //3.将最后一本书置为空
                bookList.setBooks(currentSize - 1, null);
                //数组最大容量减少
                bookList.setUseSize(currentSize - 1);
                System.out.println("删除成功！");
                return;
            }
        }
        //未删除成功的情况
        System.out.println("该书不存在，删除失败");
        return;
    }
}

BorrowOperation方法

借入图书的方法

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("借出书籍");
        /*
        * 1.你要借阅什么书
        * 2.你要借阅的书存不存在
        * 3.如何完成借阅过程 isBorrowed->true 已借出 isBorrowed->false 未借出
        * */
        System.out.println("请输入你要借阅的图书名字");
        Scanner sc = new Scanner(System.in);
        String name = sc.nextLine();
        int currentSize = booklist.getUseSize();
        for (int i = 0; i < currentSize; i++) {
            Book book = booklist.getBook(i);
            //该图书存在的情况
            if(book.getName().equals(name) && book.isBorrowed() == false) {
                book.setBorrowed(true);
                System.out.println("借出成功");
                System.out.println(book);
                return;
            }
        }

        //未被借出的情况
        System.out.println("该图书已被借出或者不存在，借阅失败");
        return;
    }
}

ReturnOperation方法

归还图书的方法

package operation;

import book.Book;
import book.BookList;

import java.util.Scanner;

public class ReturnOperatoin implements IOPeration{
    @Override
    public void work(BookList booklist) {
        System.out.println("归还书籍");
        System.out.println("请输入你要归还的图书");
        Scanner sc = new Scanner(System.in);
        String name = sc.nextLine();
        int currentSize = booklist.getUseSize();
        for (int i = 0; i < currentSize; i++) {
            Book book = booklist.getBook(i);
            //该图书存在的情况
            if(book.getName().equals(name) && book.isBorrowed() == true) {
                book.setBorrowed(false);
                System.out.println("归还成功");
                System.out.println(book);
                return;
            }
        }

        //未被借出的情况
        System.out.println("该图书已被归还或者不存在，归还失败");
        return;
    }
}

ExitOperation方法

退出系统所使用的方法。

package operation;

import book.BookList;

public class ExitOperation implements IOPeration{
    @Override
    public void work(BookList booklist) {
        System.out.println("退出系统");
        //退出系统指令
        System.exit(0);
    }
}