Java学习（11）：Java实现图书馆书库管理系统

接上次博客：Java学习（10）多接口、接口的继承、抽象类和接口的区别、Object类【toString 、equals、hashcode】、接口实例【compareTo、clone 】、浅拷贝和深拷贝、内部类_di-Dora的博客-CSDN博客

我们要想完成这个书库管理系统，首先应该理清楚它的底层逻辑。

我们一共写了三个包：

包1：book，它里面放了两个源文件，一个是Book，它代表了“Book”这个类，定义了相关的成员，代表了每本书的具体属性；一个是BookList，它可以被看作是一个书架，存放了我们拥有的图书的相关信息，可以对图书的信息进行查阅，还可以保存当前图书的数量。

包2：operation，它里面放了多个源文件，代表了可以对图书进行的一些相关操作，这些对象又都继承了一个接口IOPeration。

包3：user，针对不同的使用对象，该系统呈现的功能也会有所差异，所以这个包里面先实现了一个 User 作为父类，又实现了两个子类 NormalUser 和 AdminUser ，分别代表普通用户和管理员。

综上，整个系统的结构如下图：

下面是这个系统的基础代码，我会通过注释在相关地方说明一些需要注意的知识点：

1、TestBook/src/Main.java

import book.BookList;
import user.AdminUser;
import user.NormalUser;
import user.User;import java.util.Scanner;public class Main {//可以利用返回值，的向上转型达到返回值的一致性public static User login() {Scanner scanner = new Scanner(System.in);System.out.println("请输入你的姓名：");String name = scanner.nextLine();System.out.println("请输入你的身份：1---》管理员  0---》普通用户");int choice = scanner.nextInt();if(choice == 1) {/*AdminUser adminUser = new AdminUser(name);return adminUser;*/return new AdminUser(name);}else {/*NormalUser normalUser = new NormalUser(name);return normalUser;*/return new NormalUser(name);}}public static void main(String[] args) {BookList bookList = new BookList();User user = login();while (true) {int choice = user.menu();//user是哪个对象？ choice是几？ ---》 这些能够确定：我能够操作哪个对象的哪个方法。//通过这两个变量可以确定之后，怎么联系起来/** 1. 先让AdminUser和NormalUser存好各自对应的操作* 2. 我们就可以通过不同对象的menu调用对象对应的操作了！*/user.doOperation(choice, bookList);}}
}

2、TestBook/src/book

（1）、TestBook/src/book/Book.java

package book;public class Book {private String name;//书名private String author;//作者private int price;//价格private String type;//类型private boolean isBorrowed;//是否被借出 默认是falsepublic Book(String name, String author, int price, String type) {this.name = name;this.author = author;this.price = price;this.type = type;//因为boolean isBorrowed 默认是false ，所以我们不需要在构造函数里面再写一遍}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;}//实现我们自己的打印方法@Overridepublic String toString() {return "Book{" +"name='" + name + '\'' +", author='" + author + '\'' +", price=" + price +", type='" + type + '\'' +((isBorrowed == true) ? "  该图书已经被借出":"  该图书未被借出")+/*", isBorrowed=" + isBorrowed +*/'}';}
}

（2）、TestBook/src/book/BookList.java

package book;public class BookList {private Book[] books = new Book[10];private int usedSize;//这是一共计数器用来记录当前实际放的书的书目！public BookList() {//构造方法 来初始化成员this.books[0] = new Book("三国演义","罗贯中",50," 中国古典名著 ");this.books[1] = new Book("西游记","吴承恩",38," 中国古典名著 ");;this.books[2] = new Book("红楼梦","曹雪芹",45," 中国古典名著 ");;this.usedSize = 3;}//传入想要取得的图书的下标，得到图书public Book getBook(int pos) {return books[pos];}//传入想要放入的图书和放置的位置public void setBooks(int pos,Book book) {books[pos] = book;}public int getUsedSize() {return usedSize;}public void setUsedSize(int usedSize) {this.usedSize = usedSize;}
}

3、TestBook/src/operation

（1）、TestBook/src/operation/AddOperation.java

package operation;import book.Book;
import book.BookList;import java.util.Scanner;public class AddOperation implements IOPeration {@Overridepublic void work(BookList bookList){System.out.println("新增图书！");Scanner scanner = new Scanner(System.in);System.out.println("请输入想要添加的书的书名：");String name = scanner.nextLine();//遍历整个书架，查看是否已经添加相同书籍for(int n =0;n<bookList.getUsedSize();n++){Book book2=bookList.getBook(n);if(book2.getName().equals(name)){System.out.println("书库中已包含本书，不可以重复添加！");return;}}System.out.println("请输入想要添加的书的作者：");String author = scanner.nextLine();System.out.println("请输入想要添加的书的价格：");int price = scanner.nextInt();//记得要把回车符读取一下scanner.nextLine();System.out.println("请输入想要添加的书的类型：");String type = scanner.nextLine();Book book = new Book(name, author, price, type);int usedSize = bookList.getUsedSize() + 1;//我们需要增加一下目前拥有的书的数量bookList.setBooks(bookList.getUsedSize(), book);bookList.setUsedSize(usedSize);System.out.println("添加成功！");}
}

（2）、TestBook/src/operation/BorrowedOperation.java

package operation;import book.Book;
import book.BookList;import java.util.Scanner;public class BorrowedOperation implements IOPeration {@Overridepublic void work(BookList bookList) {Scanner scanner = new Scanner(System.in);int currentSize = bookList.getUsedSize();System.out.println("这是本书库所有藏书");for (int k = 0; k < currentSize; k++) {Book book = bookList.getBook(k);System.out.println(book);}System.out.println("请输入想要借阅的书的书名：");String nameborrow = scanner.nextLine();for (int i = 0; i < currentSize; i++) {Book book = bookList.getBook(i);if (book.getName().equals(nameborrow)) {if(!book.isBorrowed()){book.setBorrowed(true);System.out.println("借阅成功！");return;}else{System.out.println("该图书已被借出，请重新选择！");}}}System.out.println("没有你想要借阅的书！");}
}

（3）、TestBook/src/operation/DelOperation.java

package operation;import book.Book;
import book.BookList;import java.util.Scanner;public class DelOperation implements IOPeration{@Overridepublic void work(BookList bookList) {System.out.println("这是本书库现有藏书");int currentSize = bookList.getUsedSize();for (int k = 0; k < currentSize; k++) {Book book = bookList.getBook(k);System.out.println(book);}System.out.println("请输入你想要删除的书的名字:");Scanner scanner = new Scanner(System.in);/*现在遍历书架，比对是否存在与输入字符串相同的书名* 如果有，那么就把后一本数的信息前移，覆盖掉需要删除的书的信息* */String namedel = scanner.nextLine();for (int i = 0; i < currentSize; i++) {Book book = bookList.getBook(i);if (book.getName().equals(namedel)) {for(int j=i+1;j<currentSize;j++){Book booklatter = bookList.getBook(j);bookList.setBooks(j,booklatter);}//记得还要减少库存bookList.setUsedSize(bookList.getUsedSize()-1);System.out.println("删除图书成功！");return;}}}
}

我们可以再丰富一下这个代码：

public class DelOperation implements IOPeration{@Overridepublic void work(BookList bookList) {int currentSize = bookList.getUsedSize();if(currentSize==0){System.out.println("书架上现在没有书，无法删除书籍！");return;}System.out.println("这是本书库现有藏书");for (int k = 0; k < currentSize; k++) {Book book = bookList.getBook(k);System.out.println(book);}System.out.println("请输入你想要删除的书的名字:");Scanner scanner = new Scanner(System.in);String namedel = scanner.nextLine();//如果有这本书 就不能添加了int index=-1;for (int i = 0; i < currentSize; i++) {Book book = bookList.getBook(i);if (book.getName().equals(namedel)) {index=i;break;}}if(index==-1){System.out.println("本书库没有这本书，无法删除！");return;}for(int j=index;j<currentSize-1;j++){Book booklatter = bookList.getBook(j+1);bookList.setBooks(j,booklatter);}//记得还要减少库存bookList.setUsedSize(bookList.getUsedSize()-1);System.out.println("删除图书成功！");return;}
}

（4）、TestBook/src/operation/ExitOperation.java

package operation;import book.Book;
import book.BookList;public class ExitOperation implements IOPeration {@Overridepublic void work(BookList bookList) {System.out.println("退出系统！");int currentSize = bookList.getUsedSize();for (int i = 0; i < currentSize; i++) {bookList.setBooks(i,null);}bookList.setUsedSize(0);System.exit(0);}
}

（5）、TestBook/src/operation/FindOperation.java

package operation;import book.Book;
import book.BookList;import java.util.Scanner;public class FindOperation implements IOPeration{public void work(BookList bookList){Scanner scanner = new Scanner(System.in);System.out.println("请输入你要查找的图书的书名：");String name = scanner.nextLine();int currentSize = bookList.getUsedSize();for (int i = 0; i < currentSize; i++) {Book book = bookList.getBook(i);/*一定不可以这么写！* Book book = books[i];* 记住！我们现在是在面向对象！* */if(book.getName().equals(name)) {System.out.println("找到了你查找的书：");System.out.println(book);return;}}System.out.println("不好意思，本书库目前还未收藏该书！");}
}

（6）、TestBook/src/operation/IOPeration.java

package operation;import book.BookList;public interface IOPeration {void work(BookList bookList);//每个子类都要实现这个抽象的方法
}

（7）、TestBook/src/operation/ReturnOperation.java

package operation;import book.Book;
import book.BookList;import java.util.Scanner;public class ReturnOperation implements IOPeration{@Overridepublic void work(BookList bookList) {int currentSize = bookList.getUsedSize();System.out.println("请输入你想要归还的图书的书名：");Scanner scanner = new Scanner(System.in);String nameborrow = scanner.nextLine();for (int i = 0; i < currentSize; i++) {Book book = bookList.getBook(i);if (book.getName().equals(nameborrow)) {book.setBorrowed(false);System.out.println("归还图书成功！");return;}}System.out.println("没有你应该归还的书。");}
}

（8）、TestBook/src/operation/ShowOperation.java

package operation;import book.Book;
import book.BookList;public class ShowOperation implements IOPeration{@Overridepublic void work(BookList bookList) {System.out.println("这是本书库所有藏书");int currentSize = bookList.getUsedSize();for (int i = 0; i < currentSize; i++) {Book book = bookList.getBook(i);//同样的，这里也不可以这样写：//Book book = books[i];System.out.println(book);}}
}

3、TestBook/src/user

（1）、TestBook/src/user/User.java

package user;import book.BookList;
import operation.IOPeration;public abstract class User {protected String name;//姓名public IOPeration[] ioPerations;//这里我们采取的是先定义，后初始化的方式public User(String name) {this.name = name;}public abstract int menu();public void doOperation(int choice, BookList bookList) {ioPerations[choice].work(bookList);}
}

（2）、TestBook/src/user/NormalUser.java

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 BorrowedOperation(),new ReturnOperation()};}public int menu() {System.out.println("************************");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 scanner = new Scanner(System.in);int choice = scanner.nextInt();return choice;}}

（3）、TestBook/src/user/AdminUser.java

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 ShowOperation()};/*this.ioPerations = {new ExitOperation(),new FindOperation(),new AddOperation(),new DelOperation(),new ShowOperation()};*/}public int menu() {System.out.println("************************");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 scanner = new Scanner(System.in);int choice = scanner.nextInt();return choice;}}

好了，写到这里，我们的书库管理系统就大功告成了（当然了，你也可以自己加一些新的功能）！

最后我们可以来看看这个系统的运行结果：

作为管理员：