Java 期末課設再也不用擔心啦！詳解實現簡易的圖書館裏系統

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【數據結構輕鬆學】系列 Github ：https://github.com/hairrrrr/EasyJava

本文的代碼已上傳至 Github

快期末了，如果各位對自己的課設沒有頭緒，不妨借鑑一下這個簡易的圖書管理系統。

如果你有問題，歡迎與我交流！

圖解實現難點

實現

book 包

Book.java

package book;

/*
 *  Description: 圖書類
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 18:52
 */

public class Book{
    private String name;
    private String author;
    private String type;
    private boolean isBorrowed;

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

    // 注：alt + insert 建可以快速生成
    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 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 + '\'' +
                ", type='" + type + '\'' +
                ", isBorrowed=" + isBorrowed +
                '}';
    }
}

BookList.java

package book;

/*
 *  Description: 書單
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 18:57
 */

public class BookList {
    private Book[] books = new Book[100];
    private int usedSize = 0;

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

    public void setBooks(Book[] books) {
        this.books = books;
    }

    public int getUsedSize() {
        return usedSize;
    }

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

    // 初始化三本書
    public BookList(){
        books[0] = new Book("挪威的森林", "村上春樹", "小說");
        books[1] = new Book("海邊的卡夫卡", "村上春樹", "小說");
        books[2] = new Book("不能承受的生命之輕", "米蘭·昆德拉", "小說");
        this.usedSize = 3;
    }
}

operation 包

AddBook.java

package operation;

/*
 *  Description: 新增圖書
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:15
 */

import book.Book;
import book.BookList;

import java.util.Scanner;

public class AddBook implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("=========  新增圖書  =========");

        Scanner scan = new Scanner(System.in);

        System.out.println("請輸入：書名");
        String name = scan.nextLine();
        System.out.println("請輸入：作者");
        String author = scan.nextLine();
        System.out.println("請輸入：書籍類型");
        String type = scan.nextLine();
        // 書單是否借出就不用單獨的初始化了，不初始化默認爲 false

        int size = bookList.getUsedSize();

        bookList.getBooks()[size] = new Book(name, author, type);
        bookList.setUsedSize(size + 1); // 不能寫 size++ ！

        System.out.println("=========  成功！  =========");
    }
}

BorrowBook.java

package operation;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:15
 */

import book.Book;
import book.BookList;

import java.util.Scanner;

public class BorrowBook implements IOperation {
    @Override
    public void work(BookList bookList) {
        System.out.println("=========  借閱圖書  =========");
        System.out.println("請輸入：書名");
        Scanner scan = new Scanner(System.in);
        String name = scan.nextLine();

        int i;
        Book book = null;
        for(i = 0; i < bookList.getUsedSize(); i++){
            book = bookList.getBooks()[i];
            if(book.getName().equals(name)){
               break;
            }
        }

        if(i == bookList.getUsedSize()) {
            System.out.println("抱歉，未能找到 " + "《" + name + "》");
            return;
        }

        if(book.isBorrowed()){
            System.out.println("抱歉，" + "《" + name + "》" + "已經借出，過兩天再來看看吧");
        }
        else {
            book.setBorrowed(true);
            System.out.println("=========  借書成功！ =========");
        }
    }
}

DeleteBook.java

package operation;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:15
 */

import book.Book;
import book.BookList;

import java.util.Scanner;

public class DeleteBook implements IOperation {
    @Override
    public void work(BookList bookList) {
        System.out.println("=========  刪除圖書  =========");
        System.out.println("請輸入：書名");
        Scanner scan = new Scanner(System.in);
        String name = scan.nextLine();

        int i;
        Book book = null;
        int usedSize = bookList.getUsedSize();

        for(i = 0; i < usedSize; i++){
            book = bookList.getBooks()[i];
            if(book.getName().equals(name)){
                break;
            }
        }

        if(i == usedSize) {
            System.out.println("抱歉，未能找到 " + "《" + name + "》");
            return;
        }

        for(; i < usedSize - 1; i++){
            bookList.getBooks()[i] = bookList.getBooks()[i + 1];
        }
        // 如果是尾刪，我們只是簡單的將數組已經使用的大小減一；對象依然被數組引用，會造成內存泄漏
        bookList.getBooks()[usedSize - 1] = null;
        bookList.setUsedSize(usedSize - 1);

        System.out.println("=========  刪除成功  =========");
    }
}

DisplayBooks.java

package operation;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:16
 */

import book.Book;
import book.BookList;

public class DisplayBooks implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("=========  展示圖書  =========");

        for(int i = 0; i < bookList.getUsedSize(); i++){
            System.out.println(bookList.getBooks()[i].toString());
            /*上面的語句等價於下面的：
            Book[] books = bookList.getBooks();
            Book book = books[i];
            System.out.println(book.toString());*/
        }
    }
}

Exit.java

package operation;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:17
 */

import book.BookList;

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

FindBook.java

package operation;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:16
 */

import book.Book;
import book.BookList;

import java.util.Scanner;

public class FindBook implements IOperation {
    @Override
    public void work(BookList bookList) {
        System.out.println("=========  查詢圖書  =========");

        System.out.println("請輸入：書名");
        Scanner scan = new Scanner(System.in);
        String name = scan.nextLine();

        for(int i = 0; i < bookList.getUsedSize(); i++){
            Book book = bookList.getBooks()[i];
            if(book.getName().equals(name)){
                System.out.println(book.toString());
                return;
            }
        }
        System.out.println("抱歉，未能找到 " + "《" + name + "》");
    }
}

ReturnBook.java

package operation;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:16
 */

import book.Book;
import book.BookList;

import java.util.Scanner;

public class ReturnBook implements IOperation {
    @Override
    public void work(BookList bookList) {
        System.out.println("=========  歸還圖書  =========");
        System.out.println("請輸入：書名");
        Scanner scan = new Scanner(System.in);
        String name = scan.nextLine();

        for(int i = 0; i < bookList.getUsedSize(); i++){
            Book book = bookList.getBooks()[i];
            if(book.getName().equals(name)){
                bookList.getBooks()[i].setBorrowed(false);
                System.out.println("=========  歸還歸還  =========");
                return;
            }
        }
        System.out.println("抱歉，未能找到 " + "《" + name + "》");
    }
}

IOperation.java

package operation;
import book.BookList;

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:17
 */


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

user 包

Admin.java

package user;

/*
 *  Description: 管理員
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:18
 */

import book.BookList;
import operation.*;

import java.util.Scanner;

public class Admin extends User {

    public Admin(String name){
        super(name);
        this.operations = new IOperation[]{
            null,
            new FindBook(),
            new AddBook(),
            new DeleteBook(),
            new DisplayBooks(),
            new Exit(),
        };
    }

    @Override
    public int menu() {
        System.out.println("Hello, " + this.name);
        System.out.println("***********************************");
        System.out.println("**********  1. 查找圖書  ************");
        System.out.println("**********  2. 新增圖書  ************");
        System.out.println("**********  3. 刪除圖書  ************");
        System.out.println("**********  4. 打印圖書  ************");
        System.out.println("**********  5.   退出    ************");
        System.out.println("***********************************");
        Scanner scan = new Scanner(System.in);
        int choice = scan.nextInt();

        return choice;
    }

    @Override
    public void doOperation(BookList bookList, int choice) {
        this.operations[choice].work(bookList);
    }
}

NormalUser.java

package user;

/*
 *  Description: 普通用戶
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:19
 */

import book.BookList;
import operation.*;

import java.util.Scanner;

public class NormalUser extends User{

    public NormalUser(String name){
        super(name);
        this.operations = new IOperation[]{
                null,
                new FindBook(),
                new BorrowBook(),
                new ReturnBook(),
                new DisplayBooks(),
                new Exit(),
        };
    }

    @Override
    public int menu() {
        System.out.println("Hello, " + this.name);
        System.out.println("***********************************");
        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("**********  4. 打印圖書  ************");
        System.out.println("**********  5.   退出    ************");
        System.out.println("***********************************");
        Scanner scan = new Scanner(System.in);
        int choice = scan.nextInt();

        return choice;
    }

    @Override
    public void doOperation(BookList bookList, int choice) {
        this.operations[choice].work(bookList);
    }
}

User.java

package user;

/*
 *  Description: 用戶的父類
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:28
 */

import book.BookList;
import operation.IOperation;

public abstract class User {
    protected String name;

    protected IOperation[] operations;

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

    public abstract int menu();

    public abstract void doOperation(BookList bookList, int choice);
}

Main.java

/*
 *  Description:
 *  User: Shepard Wang
 *  Date: 2020 -06 -10
 *  Time: 19:19
 */

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

import java.util.Scanner;

public class Main {
    public static User login(){
        Scanner scan = new Scanner(System.in);
        System.out.println("請輸入用戶姓名");
        String name = scan.nextLine();
        System.out.println("請輸入選擇：0 -> 管理員 1 -> 用戶");
        int choice = scan.nextInt();

        if(choice == 0){
            // 向上轉型
            return new Admin(name);
        }else{
            return new NormalUser(name);
        }
    }

    public static void main(String[] args) {
        // 書單
        BookList bookList = new BookList();
        while(true) {
            // 用戶：
            User user = login();
            // 應用運行時綁定，父類引用會使用子類的 menu 方法
            int choice = user.menu();

            user.doOperation(bookList, choice);
        }

    }
}

---

查看【0 基礎學 Java】更詳細的目錄： https://github.com/hairrrrr/EasyJava

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