实现的样子 首先让我们来看一下系统实现以后大致的样子
如果说要做一个大致这样子的图书管理系统,那么我们要有大致的思路:
首先我们要创建三个包,user,operation,book
大致思路 要有书对吧,所以创建Book类存放每本书的基本信息 图书馆有很多书对吧,所以创建Books类存放好几本书,里面放了一个Book类型的数组和一个usedSize表示总共书的数目 有两种不同的人,管理员和用户,总共有7个功能,也就是要写7个功能类
然后我们发现,这7个功能类都要定义这么一个work方法,而且都是对BookList进行操作的,因此我们可以设置一个接口IOperation,让这些功能类实现这个接口
然后我们再看User这个包,这里面有两种用户,一个是管理员,一个是普通用户,注意到他们都有各自的菜单,同时他们都有姓名等一些公共的属性,所以这里我们可以定义一个User父类,让AdminUser和 NormalUser去继承这个类。
注意到这里的菜单不一样,可以分别再AdminUser和NormalUser里面都定义一个menu方法,但是这样不灵活,所以我们可以在User类里面定义一个空的menu方法,然后让另外两个类去实现,以后还可以方便进行多态(动态绑定),更加灵活,注意到menu是空的,所以可以设置成abstract方法,同时User类也要改为abstract类。 注意这里menu显示了以后要输入一个数字代表你要使用的功能,所以需要返回一个数字代表你所使用的功能,这里可以把menu方法定义为返回值为int型的方法 现在我们在最外面新建一个Main类,里面写main方法,在main方法之前我们写一个login方法,用来读入用户的名称以及他的用户类型,如果是管理员,返回一个AdminUser对象,如果是普通用户,返回一个NormalUser对象,这里注意把login()方法的返回值设置为User对象,然后再main方法中User user = login;然后user.menu();显示出菜单,这里就使用了多态,通过返回值让父类引用引用了子类的对象,同时父类的引用调用了子类重写过的同名方法。 最巧妙的一步,我们现在的user已经完成了动态绑定,相当于已经知道了他是管理员还是普通用户,接下来要做的就是根据choice的值来调用相应的操作类。
现在你只有一个user,所以根据choice调用不同的操作这个方法自然也应该在user这个类中。首先在User内部定义一个成员变量,操作接口的数组,用于存放不同的操作类
然后在AdminUser和NormalUser按顺序初始化这些操作类,这里相当于IOperation接口发生了向上转型
在User里面定义doOperation方法,根据choice调用不同操作类的work方法对booklist数组进行操作
10.由于选择功能使用一次以后,不能直接退出,需要再次显示菜单,所以我们将选择菜单和调用相应方法这两个语句写到死循环中
11.接下来就只需要写那几个功能类就可以了
12.ExitOperation,System.exit(0);即可
13.AddOperation,很简单,让用户输入图书相应的信息,然后新建一个book类,初始化放到bookList的usedSize位置即可,之后别忘了更新usedSize
14.FindOperationn,fori遍历即可,每一次遍历可以先定义一个book对象,然后比较该对象的名称与输入的名称是否一样,如果找到了,提示并打印,然后直接return;这样就不用设置flag了,如果走出了for循环还没有return,那么就说明没找到,提示没找到即可。
15.DisplayOperation,fori遍历即可
16.BorrowOperation,ReturnOperation,对相应isBorrowed变量进行相应操作即可
代码 (按照这个目录创建包) 代码亲测能正常运行,如果不想自己慢慢新建类的话,可以点击下面链接自取。不过其实新建类也挺快的,要注意不要把类的名字建错。有什么不会弄的都可以评论问我。
Library.rar-Java文档类资源-CSDN下载
、
首先是book包下,有两个类
book类 package Library.book;
public class Book { private String name; private String author; private int price; private String type; private boolean isBorowed; //默认是flase,默认没有被借,所以可以不用初始化 public Book(String name, String author, int price, String type) { this.name = name; this.author = author; this.price = price; this.type = type; //默认是flase,默认没有被借,所以可以不用初始化 }
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 isBorowed() {
return isBorowed;
}
public void setBorowed(boolean borowed) {
isBorowed = borowed;
}
@Override
public String toString() {
return "book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type + '\'' +
", isBorowed=" + isBorowed +
'}';
}
}
bookList类 package Library.book;
public class BookList { private Book[] books = new Book[10]; private int usedSize = 0; public BookList(){ books[0] = new Book("游戏人生","榎宫祐",12,"轻小说"); books[1] = new Book("见面5秒开始战斗","肠才藏",20,"漫画"); books[2] = new Book("碧蓝之海","井上竖二",25,"漫画"); this.usedSize = 3; }
public Book getBook(int pos) { //取pos位置的那本书
return this.books[pos];
}
public void setBook(int pos, Book book) { //将pos位置的书置为book
this.books[pos] = book;
}
public int getUsedSize() {
return usedSize;
}
public void setUsedSize(int usedSize) {
this.usedSize = usedSize;
}
}
然后是operation包下,有7个类和1个接口
AddOperation类 package Library.operation;
import Library.book.Book; import Library.book.BookList;
import java.util.Scanner;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/18
- Time: 22:43
- Description:新增图书 */ public class AddOperation implements IOperation { public void work(BookList bookList){ Scanner scanner = new Scanner(System.in); System.out.println("新增图书"); //只需要放到当前数组的usedSize位置 System.out.println("请输入图书的名字:"); String name = scanner.next(); System.out.println("请输入图书的作者:"); String author = scanner.next(); System.out.println("请输入图书的价格:"); int price = scanner.nextInt(); System.out.println("请输入图书的类型:"); String type = scanner.next(); Book book = new Book(name,author,price,type); int curSize = bookList.getUsedSize(); bookList.setBook(curSize,book); bookList.setUsedSize(curSize+1); System.out.println("图书添加成功!"); }
}
BorrowOperation类 package Library.operation;
import Library.book.Book; import Library.book.BookList;
import java.util.Scanner;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:02
- Description: 借阅书籍 */ public class BorrowOperation implements IOperation { public void work(BookList bookList){ System.out.println("借阅书籍"); Scanner scanner = new Scanner(System.in); System.out.println("请输入需要借阅的图书名称:"); String name = scanner.next(); for (int i = 0; i < bookList.getUsedSize(); i++) { Book book = bookList.getBook(i); if (book.getName().equals(name)){ if (!book.isBorowed()){ book.setBorowed(true); //如果找到该书,且该书没有被借阅,那就借阅成功 System.out.println("图书借阅成功!"); }else { System.out.println("该图书已被借阅!"); } return; } } System.out.println("该图书不存在!"); //走到这里说明这本书不存在 } }
DelOperation类 package Library.operation;
import Library.book.Book; import Library.book.BookList;
import java.util.Scanner;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:03
- Description: 删除图书 */ public class DelOperation implements IOperation{ public void work(BookList bookList){ Scanner scanner = new Scanner(System.in); System.out.println("删除图书"); System.out.println("请输入要删除的图书名称:"); String name = scanner.next(); int n = bookList.getUsedSize(); for (int i = 0; i < n; i++) { Book book = bookList.getBook(i); if (book.getName().equals(name)){ for (int j = i; j < n-1; j++) { bookList.setBook(j,bookList.getBook(j+1)); } bookList.setUsedSize(n-1); System.out.println("图书删除成功!"); return; //如果找到了并且删除成功,就return } } System.out.println("对不起,没有找到您需要删除的书!"); //如果没有for循环中没有return,那就是没有找到 } }
DisplayOperation类 package Library.operation;
import Library.book.BookList;
/**
-
Created with IntelliJ IDEA.
-
User: 13498
-
Date: 2021/11/22
-
Time: 14:03
-
Description: 显示书籍 */ public class DisplayOperation implements IOperation { public void work(BookList bookList){ System.out.println("显示书籍"); for (int i = 0; i < bookList.getUsedSize(); i++) { System.out.println(bookList.getBook(i)); }
} }
ExitOperation类 package Library.operation;
import Library.book.BookList;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:04
- Description: 退出系统 */ public class ExitOperation implements IOperation { public void work(BookList bookList){ System.out.println("退出系统"); System.exit(0); //退出系统 } }
FindOperation类 package Library.operation;
import Library.book.Book; import Library.book.BookList;
import java.util.Scanner;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:04
- Description: 查找图书 */ public class FindOperation implements IOperation{ public void work(BookList bookList){ Scanner scanner = new Scanner(System.in); System.out.println("查找图书"); System.out.println("请输入图书的名称:"); String name = scanner.next(); for (int i = 0; i < bookList.getUsedSize(); i++) { Book book = bookList.getBook(i); if (book.getName().equals(name)){ System.out.println("找到该图书!"); System.out.println(book); return; //如果找到了,就直接return出去 } } System.out.println("对不起,没有找到此书!"); //如果走到这一步,那么说明没有在for循环return出去,那就显示没找到 } }
ReturnOperation类 package Library.operation;
import Library.book.Book; import Library.book.BookList;
import java.util.Scanner;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:04
- Description: 归还图书 */ public class ReturnOperation implements IOperation{ public void work(BookList bookList){ System.out.println("归还图书"); Scanner scanner = new Scanner(System.in); System.out.println("请输入需要归还的图书名称:"); String name = scanner.next(); for (int i = 0; i < bookList.getUsedSize(); i++) { Book book = bookList.getBook(i); if (book.getName().equals(name)){ if (book.isBorowed()){ book.setBorowed(false); //如果找到该书,且该书已被借阅,那就归还成功 System.out.println("图书归还成功!"); }else { System.out.println("该图书未被借阅!"); } return; } } System.out.println("该图书不存在!"); //走到这里说明这本书不存在 } }
IOperation接口 package Library.operation;
import Library.book.BookList;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:06
- Description: No Description */ public interface IOperation { void work(BookList bookList); } 最后是user包下,有3个类
AdminUser类 package Library.user;
import Library.operation.*;
import java.util.Scanner;
/**
-
Created with IntelliJ IDEA.
-
User: 13498
-
Date: 2021/11/22
-
Time: 14:19
-
Description: No Description */ 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("========================================"); System.out.println("尊贵的管理员-"+this.name+",欢迎使用本图书管理系统"); 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.显示所有图书"); System.out.println("0.退出系统"); System.out.println("========================================"); System.out.print("请输入数字以使用相应的功能:"); Scanner scanner = new Scanner(System.in); int n = scanner.nextInt(); return n; }
}
NormalUser类 package Library.user;
import Library.operation.*;
import java.util.Scanner;
/**
-
Created with IntelliJ IDEA.
-
User: 13498
-
Date: 2021/11/22
-
Time: 14:19
-
Description: No Description */ 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("========================================"); System.out.println("尊贵的用户-"+this.name+",欢迎使用本图书管理系统"); 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.print("请输入数字以使用相应的功能:"); Scanner scanner = new Scanner(System.in); int n = scanner.nextInt(); return n; }
}
User类 package Library.user;
import Library.book.BookList; import Library.operation.IOperation;
/**
-
Created with IntelliJ IDEA.
-
User: 13498
-
Date: 2021/11/22
-
Time: 14:18
-
Description: No Description */ public abstract class User { protected String name; IOperation[] IOperations;
public User(String name) { this.name = name; }
public abstract int menu(); public void doOperations(int choice, BookList bookList){ IOperations[choice].work(bookList); } }
还有一个外边的Main类
Main类 package Library;
import Library.book.BookList; import Library.user.AdminUser; import Library.user.NormalUser; import Library.user.User;
import java.util.Scanner;
/**
- Created with IntelliJ IDEA.
- User: 13498
- Date: 2021/11/22
- Time: 14:44
- Description: No Description */ public class Main { public static User login(){ System.out.println("请输入您的姓名"); Scanner scanner = new Scanner(System.in); String name = scanner.nextLine(); System.out.println("请输入您的身份:1 -> 管理员 0 -> 普通用户"); int n = scanner.nextInt(); if (n == 1){ return new AdminUser(name); }else { return new NormalUser(name); } } public static void main(String[] args) { BookList bookList = new BookList(); //准备了书籍 User user = login(); //向上转型 while(true){ //写成死循环,这样就会不断的调用菜单,直到选择退出系统 int choice = user.menu(); //动态绑定调用menu方法,choice表示你的选择 user.doOperations(choice,bookList); } } } OK,就这些了,代码能运行无bug,如果有什么地方出错了或者有什么不懂都可以评论问我。