前言
学习完java面向对象语法后，做一个图书系统来熟悉语法。
文章目录
🚀1.需求分析
通过上图可知图书管理系统的使用者分为图书管理员以及普通用户，并且管理员与普通用户对图书系统的使用权限有所差异。但是无论是图书管理员还是普通用户都是对书籍进行操作，为此需要一个书架来存储书籍，然后使书架具备CURD功能即可，最后可以给使用者使用了。
🚀2.具体实现
🚀3.项目文件划分
创建项目后，在scr下分别创建book包，booklist,operation以及user包对所需的类进行管理，book包下为书籍类，booklist下为书架,operation下为书架的具体功能实现，user下用户所在处。
🚀4.book类
给予书籍类一些基本属性如书名，作者，价格，类型，是否被借阅等属性。
package book; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 12:57 */ public class Book { private String name; private String author; private int price; private String type; private boolean borrow; public Book(String name, String author, int 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 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 isBorrow() { return borrow; } public void setBorrow(boolean borrow) { this.borrow = borrow; } @Override public String toString() { return "Book{" + "name='" + name + '\'' + ", author='" + author + '\'' + ", price=" + price + ", type='" + type + '\'' + ", borrow=" + borrow + '}'; } }
🚀5.BookList类
所谓的书架就是存放书籍的容器，再此使用数组来存储书籍，默认书架上四大名著且只容纳10本书。我们使用userSized变量记录书架上的已有的书籍
package booklist; import book.Book; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 13:00 */ public class BookList { private Book[] books=new Book[10]; private int userSized; public BookList() { books[0]=new Book("红楼梦","曹雪芹",90,"小说"); books[1]=new Book("三国演义","罗贯中",80,"小说"); books[2]=new Book("西游记","吴承恩",70,"小说"); books[3]=new Book("水浒传","施耐庵",60,"小说"); this.userSized = 4; } public Book getBook(int pos) {//通过pos在书架上获得图书 if(pos<0||pos>books.length){ return null; } return books[pos]; } public void setBooks(int pos,Book book) {//根据pos书架上设置图书 if(pos<0||pos>books.length){ return ; } books[pos]=book; } public int getUserSized() {//获得书架已使用的空间 return userSized; } public void setUserSized(int userSized) {//重置书架已使用的空间 this.userSized = userSized; } }
🚀6.IOperations接口
该接口是对图书操作的一个规范，
package operation; import booklist.BookList; public interface IOperations { void work(BookList list); }
🚀1.新增图书功能
package operation; import book.Book; import booklist.BookList; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 13:13 */ public class AddBook implements IOperations { @Override public void work(BookList list) { Scanner sc = new Scanner(System.in); System.out.println("请输入你要新增的书名："); String name = sc.next(); System.out.println("请输入你要新增图书的作者："); String author = sc.next(); System.out.println("请输入书的价格"); int price = sc.nextInt(); System.out.println("请输入你要新增图书的类型："); String type = sc.next(); Book book = new Book(name, author, price, type); int currentSize = list.getUserSized(); list.setBooks(currentSize, book); list.setUserSized(currentSize + 1); System.out.println("添加成功"); } }
🚀2.借阅图书功能
属性borrow默认为false即未接出，只需将其置为true就表示书籍已接出。
package operation; import book.Book; import booklist.BookList; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 20:20 */ public class BorrowBook implements IOperations { @Override public void work(BookList list) { Scanner sc = new Scanner(System.in); System.out.println("请输入你要借的书名："); String name = sc.next(); for(int i=0;i<list.getUserSized();i++){ Book book=list.getBook(i); if(name.equals(book.getName())){ book.setBorrow(true); System.out.println("已成功借书"); return ; } } } }
🚀3.删除图书功能
储存书籍的容器为数组，我们可以先根据书名在书架中查找书籍书否存在，若存在则在数组中将后面的书籍覆盖要删除的书籍即可。
package operation; import book.Book; import booklist.BookList; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 13:12 */ public class DeleteBook implements IOperations { @Override public void work(BookList list) { Scanner sc = new Scanner(System.in); System.out.println("删除图书！"); System.out.println("请输入你要删除的图书："); String name = sc.next(); int i=0; int index=0; for ( i = 0; i < list.getUserSized(); i++) { Book book = list.getBook(i); if (name.equals(book.getName())) { index = i; break; } } if (i>=list.getUserSized()) { System.out.println("没有找到此书"); return ; } for (int j = index; j < list.getUserSized(); j++) { Book book=list.getBook(j+1); list.setBooks(j,book); } list.setBooks(list.getUserSized()-1,null);//将没有书籍的位置置null，避免内存泄露 list.setUserSized(list.getUserSized()-1); System.out.println(name+"删除了"); } }
🚀4.退出系统功能
使用System的exit()方法终止JVM的运行，就是结束退出系统。exit中的参数非0表示异常终止。
package operation; import booklist.BookList; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 20:18 */ public class ExitOperation implements IOperations { @Override public void work(BookList list) { System.exit(0); System.out.println("退出成功！"); } }
🚀5.归还图书功能
将该图书的属性borrow置为false即可。
package operation; import book.Book; import booklist.BookList; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 20:12 */ public class ReturnBook implements IOperations { @Override public void work(BookList list) { System.out.println("归还图书"); Scanner sc = new Scanner(System.in); System.out.println("情书输入你要归还图书的书名："); String name = sc.next(); int currentSize= list.getUserSized(); for(int i=0;i<currentSize;i++){ Book book = list.getBook(i); if(name.equals(book.getName())){ book.setBorrow(false); System.out.println("归还成功"); return ; } } } }
🚀6.查找图书功能
根据书名在书籍查找图书即可。
package operation; import book.Book; import booklist.BookList; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 13:12 */ public class SearchBook implements IOperations { @Override public void work(BookList list) { Scanner sc = new Scanner(System.in); System.out.println("请输入你要查找的书名："); String name=sc.next(); for(int i=0;i<list.getUserSized();i++){ Book book=list.getBook(i); if(name.equals(book.getName())){ System.out.println("找到啦"); System.out.println(book); return ; } } System.out.println("很遗憾,没有找到！"); } }
🚀7.显示图书功能
因为图书类已经重写了toString()方法，只需遍历书架上的图书将 其打印出来就能得到图书的信息。
package operation; import booklist.BookList; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 13:15 */ public class ShowBook implements IOperations { @Override public void work(BookList list) { System.out.println("显示图书："); for(int i=0;i<list.getUserSized();i++){ System.out.println(list.getBook(i)); } } }
🚀8.User
图书管理员以及普通用户都是用户，故定义一个父类，在User中定义基本属性name，并提供构造器。由于图书管理员与普通用户的权限不同，也就是登录到系统时所遇到的菜单是不一致得到，所以定义一个抽象的menu()方法供子类具体实现。有因为图书管理员和普通用户的功能不一致，为此在父类中提供一个doOperation()方法，可以根据用户在菜单的选择去调用对应的方法。
package user; import booklist.BookList; import operation.IOperations; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 13:15 */ public abstract class User { protected String name; protected IOperations [] ip; public abstract int menu(); public User(String name){ this.name=name; } public void doOperation(int choice, BookList List){ this.ip[choice].work(List); } }
🚀8.1RootUser类
package user; import operation.*; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 12:57 */ public class RootUser extends User { public RootUser(String name) { super(name); this.ip = new IOperations[]{ new ExitOperation(), new SearchBook(), new AddBook(), new DeleteBook(), new ShowBook() }; } @Override public int menu() { System.out.println(this.name + "欢迎来到图书馆"); Scanner sc = new Scanner(System.in); 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.退出图书："); System.out.println("请输入你的选择："); int choice = sc.nextInt(); return choice; } }
🚀8.2NormalUser类
package user; import operation.*; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 12:56 */ public class NormalUser extends User{ public NormalUser(String name) { super(name); this.ip=new IOperations[]{ new ExitOperation(), new SearchBook(), new BorrowBook(), new ReturnBook(), }; } @Override public int menu() { Scanner sc = new Scanner(System.in); System.out.println(this.name+"欢迎来到图书馆"); 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.退出图书："); System.out.println("请输入你的选择："); int choice=sc.nextInt(); return choice; } }
🚀9.系统启动类
提供login方法根据id确定使用者的身份，最后将用户的选择和书架传入doOperation()方法即可。
import booklist.BookList; import user.NormalUser; import user.RootUser; import user.User; import java.util.Scanner; /** * truth:talk is cheap, show me the code * * @author KC萧寒 * @description * @createDate: 2022-05-19 20:50 */ public class Start { public static void main(String[] args) { User use=login(); BookList list=new BookList(); while (true){ int chiose=use.menu();//利用多态对书架操作 use.doOperation(chiose,list); } } private static User login() {//根据id判断用户对象 Scanner sc = new Scanner(System.in); System.out.println("请输入你的姓名："); String name = sc.next(); System.out.println("请输入你的身份：1-》管理员,0-》普通用户"); int id = sc.nextInt(); if (id == 1) { return new RootUser(name); } else { return new NormalUser(name); } } }
最后的话
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