快來看看你學校的圖書管理系統的底層代碼吧

2.系統使用效果

2.1管理員系統

查找圖書

新增圖書和顯示圖書

2.2普通用戶使用系統

查找圖書

借閱圖書的歸還圖書

3.圖書存盤類

1.創建一個book包，用來表示存盤書的檔案

在book包里創建Book類，作為一本書

package book;

public class Book {
    private String name;//書名
    private String author;//作者
    private double price;//價格
    private String type;//型別
    private boolean isBorrowed;//是否借出

    public Book(String name, String author, double 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 double getPrice() {
        return price;
    }

    public void setPrice(double 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;
    }

    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ((isBorrowed == true) ? " 已經被借出 " : " 未被借出 ")+
                '}';
    }
}

在book包里創建BookList 類，用來存盤書

package book;

public class BookList {
    private Book[] books = new Book[10];
    private int usedSize;
    public BookList() {
        books[0] = new Book("平凡的世界","路遙",34.0,"小說");
        books[1] = new Book("百萬英鎊","馬克.吐溫",20.0,"小說");
        books[2] = new Book("追風箏的人","胡塞尼",30.0,"小說");
        this.usedSize = 3;
    }

    public int getUsedSize() {
        return usedSize;
    }

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

    /**
     * 獲取到pos 位置的一本書
     * @param pos
     * @return
     */

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

    /**
     * 設定下標為一本書
     * @param pos
     * @param book
     */

    public void setBooks(int pos,Book book) {
        this.books[pos] = book;
    }

}

4.創建用戶相關的類

創建一個user包

4.1在user包里面先創建一個User 類，這是一個抽象類

package user;

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 doWork(int choice, BookList bookList) {
        iOperations[choice].work(bookList);
    }

}

4.2創建管理員類 AdmiUser，是User 的子類

package user;

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() {
        System.out.println("-----------------管理員選單-----------------");
        System.out.println("hello "+ this.name +" 歡迎來到圖書管理系統");
        System.out.println("1.查找圖書");
        System.out.println("2.新增圖書");
        System.out.println("3.洗掉圖書");
        System.out.println("4.顯示圖書");
        System.out.println("0.退出系統");
        System.out.println("------------------------------------------");

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

4.3創建普通用戶使用類 NormalUser ,是User 的子類

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 ReturnOperation(),
        };
    }

    public int menu() {
        System.out.println("-----------------普通用戶選單-----------------");
        System.out.println("hello "+ this.name +" 歡迎來到圖書使用系統");
        System.out.println("1.查找圖書");
        System.out.println("2.借閱圖書");
        System.out.println("3.歸還圖書");
        System.out.println("0.退出系統");
        System.out.println("------------------------------------------");

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

5.創建操作相關的類

先創建一個operation包，然后在包里面創建操作類

5.1各個類的介面 IOperation

package operation;

import book.BookList;

import java.util.Scanner;

public interface IOperation {

    Scanner scanner = new Scanner(System.in);
    void work(BookList bookList);
}

5.2新增圖書類AddOperation

package operation;

import book.Book;
import book.BookList;

public class AddOperation implements IOperation{

    public void work(BookList bookList) {
        System.out.println("新增圖書！");
        System.out.println("請輸入圖書的名字： ");
        String name = scanner.nextLine();
        System.out.println("請輸入圖書的作者：");
        String author = scanner.nextLine();
        System.out.println("請輸入圖書的型別：");
        String type = scanner.nextLine();
        System.out.println("請輸入圖書的價格：");
        double price = scanner.nextDouble();

        Book book = new Book(name,author,price,type);
        int size = bookList.getUsedSize();
        bookList.setBooks(size,book);
        bookList.setUsedSize(size+1);
        System.out.println("新增圖書成功");

    }

}

5.3借閱圖書類BorrowOperation

package operation;

import book.Book;
import book.BookList;

public class BorrowOperation implements IOperation{

    public void work(BookList bookList) {

        System.out.println("借閱圖書");
        System.out.println("請輸入你要借閱的圖書名：");
        String name = scanner.nextLine();
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            if (name.equals(book.getName())) {
                book.setBorrowed(true);
                System.out.println("借閱成功");
                System.out.println(book);
                return;
            }
        }
        System.out.println("查無此書，請重新查找");
    }

}

5.4洗掉圖書類DelOperation

package operation;

import book.Book;
import book.BookList;

public class DelOperation implements IOperation{

    public void work(BookList bookList) {
        System.out.println("洗掉圖書！");
        //根據書名找到書的位置 index
        System.out.println("請輸入你要洗掉的圖書名");
        String name = scanner.nextLine();
        int currentSize = bookList.getUsedSize();
        int index = 0;//存盤找到的下標
        int i = 0;
         for (;i < currentSize; i++) {
             Book book = bookList.getPos(i);
             if (book.getName().equals(name)) {
                 index = i;
                 break;
             }
         }
         if (i >= currentSize) {
             System.out.println("沒有你要洗掉的書");
             return;
         }
         //2.進行洗掉
        for (int j = index; j < currentSize - 1; j++) {
            Book book = bookList.getPos(j+1);
            bookList.setBooks(j,book);//把書往前移一步
        }
        bookList.setBooks(currentSize,null);
        bookList.setUsedSize(currentSize-1);
        System.out.println("洗掉成功！");

    }
}

5.5列印圖書類DisplayOperation

package operation;

import book.Book;
import book.BookList;

public class DisplayOperation implements IOperation{

    public void work(BookList bookList) {
        System.out.println("列印圖書！");
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            System.out.println(book);
        }

    }

}

5.6查找圖書類FindOperation

package operation;

import book.Book;
import book.BookList;
import com.sun.media.jfxmediaimpl.HostUtils;

public class FindOperation implements IOperation{

    public void work(BookList bookList) {
        System.out.println("查找圖書！");
        System.out.println("請輸入你要查找的書名");
        String name = scanner.nextLine();
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            if (book.getName().equals(name)) {
                System.out.println("找到的書資訊如下");
                System.out.println(book);
                return;
            }
        }
        System.out.println("查無此書");

    }
}

5.7歸還圖書類ReturnOperation

package operation;

import book.Book;
import book.BookList;

public class ReturnOperation implements IOperation{

    public void work(BookList bookList) {
        System.out.println("歸還圖書！");
        System.out.println("請輸入你要歸還的圖書名：");
        String name = scanner.nextLine();
        int size = bookList.getUsedSize();
        for (int i = 0; i < size; i++) {
            Book book = bookList.getPos(i);
            if (name.equals(book.getName())) {
                book.setBorrowed(false);
                System.out.println("歸還成功！");
                System.out.println(book);
                return;
            }
        }
        System.out.println("你要歸還的圖書不屬于改系統");

    }
}

5.8退出系統類ExitOperation

package operation;

import book.BookList;

public class ExitOperation implements IOperation{

    public void work(BookList bookList) {
        System.out.println("退出系統！");
        System.exit(0);

    }
}

6.Main 類和main 方法

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

import java.util.Scanner;

/**
 * 整個程式的入口
 */
public class Main {

    public static User login() {
        System.out.println("請輸入你的姓名");
        Scanner scanner = new Scanner(System.in);
        String name = scanner.nextLine();
        System.out.println("請輸入你的身份：1.管理員    0.普通用戶");
        int choice = scanner.nextInt();
        if(choice == 1) {
            return new AdminUser(name);
        }else {
            return new NormalUser(name);
        }

    }

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

        while (true) {
            int choice = user.menu();//發生了動態系結--多型
            user.doWork(choice,bookList);

        }

    }
}