一.设计思路

首先这个系统可以由俩种用户使用，分别为管理者用户和普通者用户，根据不同的用户有不同的界面，每个界面有不同的功能。

二.代码实现

创建三个包和一个类

book包：包括Book类和Booklist类

Book类：

package book;
public class Book {private String name;  private String author;private int price;private String type;private boolean isborrow;
//构造方法public Book(String name, String author, int price, String type) {  //初始化this.name = name;this.author = author;this.price = price;this.type = type;}
//重写toString方法，利于后续对象的打印@Overridepublic String toString() {return "Book{" +"name='" + name + '\'' +", author='" + author + '\'' +", price=" + price +", type='" + type + '\'' +", " + ((isborrow==true)?"已借出":"未借出") +'}';}
//public boolean isIsborrow() {      //来判断是否借出return isborrow;}public void setIsborrow(boolean isborrow) { //来设置是否借出this.isborrow = isborrow;}
}

Booklist类：

package book;public class Booklist {private int brrownum;private Book[] books=new Book[10]; //表示可以放11本书
//构造方法public Booklist() {                //初始化this.books[0]=new Book("三国演义","罗贯中",20,"小说");this.books[1]=new Book("红楼梦","曹雪芹",20,"小说");this.books[2]=new Book("西游记","吴承恩",20,"小说");this.brrownum=3;         //表示已借出的书}
//封装成员的访问方法public int getBrrownum() {   //返回已借出的书的数量return brrownum;}public void setBrrownum(int brrownum) {    //调整删除或增加时已借出的书的数量this.brrownum = brrownum;}public Book getBook(int pos) {    //得到某本书的位置return books[pos];}public void setBook(Book books,int currentNum) {   //用于新增书this.books[currentNum] = books;}
}

user包：User类、AdminUser类、Normaluser类

User类：

package user;import Opeartion.Operation;
import book.Booklist;public abstract class User {public Operation[] operation;     public abstract int meau();   public void doOpearation(int choice, Booklist booklist){this.operation[choice].work(booklist);}
}

AdminUser类：

public class AdminUser extends User{public AdminUser(){               //每个数组成员代表了不同的功能this.operation=new Operation[]{new ExitSystem(),new FindBook(),new AddBook(), new DelBook(),new ShowBook()};}@Override         //重写了抽象父类User的方法public int meau(){System.out.println("***********************");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("其输入你的选择：");Scanner scanner=new Scanner(System.in);int choice=scanner.nextInt();return choice;}
}

Normaluser类：

import Opeartion.*;import java.util.Scanner;public class Normaluser extends User {public Normaluser(){this.operation=new Operation[]{new ExitSystem(),new FindBook(),new BorrowBook(),new ReturnBook(),};}@Overridepublic int meau(){System.out.println("***********************");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("其输入你的选择：");Scanner scanner=new Scanner(System.in);int choice=scanner.nextInt();return choice;}
}

Operation包：包括了各种功能的类和一个接口

Operation接口：

package Opeartion;import book.Booklist;public interface Operation {  void work(Booklist booklist);
}

ReturnBook类：

package Opeartion;import book.Booklist;import java.util.Scanner;public class ReturnBook implements Operation{@Overridepublic void work(Booklist booklist) {System.out.println("归还图书....");Scanner scanner =new Scanner(System.in);System.out.println("请输入归还书的名字：");String name=scanner.nextLine();int currentSize=booklist.getBrrownum();   //利用改变量进行数组遍历for (int i = 0; i < currentSize; i++) {if (booklist.getBook(i).getName().equals(name)){booklist.getBook(i).setIsborrow(false);System.out.println("归还成功！");return;}}System.out.println("没有你要归还的书.....");}
}

AddBook类：

package Opeartion;import book.Book;
import book.Booklist;import java.util.Scanner;public class AddBook implements Operation {@Overridepublic void work(Booklist booklist) {System.out.println("新增图书......");Scanner scanner =new Scanner(System.in);System.out.println("请输入新增书的名字：");String name=scanner.nextLine();System.out.println("请输入新增书的作者：");String author=scanner.nextLine();System.out.println("请输入新增书的价格：");int price =scanner.nextInt();    scanner.nextLine();            //清除换行符System.out.println("请输入新增书的类型：");String type =scanner.nextLine();int currentSize=booklist.getBrrownum();for (int i = 0; i < currentSize; i++) {if (booklist.getBook(i).getName().equals(name)){System.out.println("已有这本书了，不能插入！");return;}}Book newbook =new Book(name,author,price,type);  //创建新书booklist.setBook(newbook,currentSize);booklist.setBrrownum(currentSize+1);System.out.println("新增成功！");}
}

BorrowBook类：

package Opeartion;import book.Booklist;import java.util.Scanner;public class BorrowBook implements Operation{@Overridepublic void work(Booklist booklist) {System.out.println("借阅图书");Scanner scanner =new Scanner(System.in);System.out.println("请输入借阅书的名字：");String name=scanner.nextLine();int currentSize=booklist.getBrrownum();for (int i = 0; i < currentSize; i++) {if (booklist.getBook(i).getName().equals(name)){if(booklist.getBook(i).isIsborrow()){System.out.println("该书已被借出了");return;}else {booklist.getBook(i).setIsborrow(true);System.out.println("借阅成功！");return;}}}System.out.println("没有你要找的书，借阅失败！");}
}

ExitSystem类：

package Opeartion;import book.Booklist;public class ExitSystem implements Operation{@Overridepublic void work(Booklist booklist) {System.out.println("退出系统...");System.exit(0);  //退出系统}
}

ShowBook类：

package Opeartion;import book.Booklist;import java.util.Scanner;public class ShowBook implements Operation{@Overridepublic void work(Booklist booklist) {System.out.println("显示图书....");Scanner scanner =new Scanner(System.in);int currentSize=booklist.getBrrownum();for (int i = 0; i < currentSize; i++) {System.out.println(booklist.getBook(i));}}}

DelBook类：

package Opeartion;import book.Book;
import book.Booklist;import java.util.Scanner;public class DelBook implements Operation{@Overridepublic void work(Booklist booklist) {System.out.println("删除图书...");Scanner scanner =new Scanner(System.in);System.out.println("请输入删除书的名字：");String name=scanner.nextLine();int currentSize=booklist.getBrrownum();int pos =1;int i=0;for (i = 0; i < currentSize; i++) {if (booklist.getBook(i).getName().equals(name)){pos=i;break;}}if (i==currentSize){System.out.println("没有你删除的书！");return;}for (int j = i; j < currentSize-1; j++) {   //currentSize-1 是防止指针越界booklist.setBook(booklist.getBook(j+1),j);}booklist.setBook(null,currentSize-1);   //为空指针后其对象会被收回booklist.setBrrownum(currentSize-1);System.out.println("删除成功！");}
}

FindBook类：

package Opeartion;import book.Booklist;import java.util.Scanner;public class FindBook implements Operation{@Overridepublic void work(Booklist booklist) {System.out.println("查找图书....");Scanner scanner =new Scanner(System.in);System.out.println("请输入查找书的名字：");String name=scanner.nextLine();int currentSize=booklist.getBrrownum();for (int i = 0; i < currentSize; i++) {if (booklist.getBook(i).getName().equals(name)){System.out.println("找到了！");System.out.println(booklist.getBook(i));return;}}System.out.println("没有你要找的书.....");}
}

Main类：

import book.Booklist;
import user.AdminUser;
import user.Normaluser;
import user.User;import java.util.Scanner;public class Main {public static User login(){System.out.println("其输入你的名字：");Scanner scanner =new Scanner(System.in);String name =scanner.nextLine();while (true){System.out.println("请输入你的身份：1.管理员  2.用户");int choice =scanner.nextInt();if(choice==1){return new AdminUser();}else if (choice==2){return new Normaluser();}else {System.out.println("输入错误请重新输入");}}}public static void main(String[] args) {Booklist booklist=new Booklist();User user =login();   //打印界面while (true){int choice=user.meau();  //打印对应的菜单user.doOpearation(choice,booklist);}}
}