具体内容如下

思路：所有包都在book_manage包里

利用面向对象的多态特性去除了很多if-else的判断，不同的子类在父类所对应的方法不同。

1.首先建立一个book包

包里面有2个类，一个是Book,这个类里面包含一本书的全部信息另外一个类是BookList，这个类是用来管理每一个书，通过这个类来寻找每一本书。private Book[] books = new Book[100];Book数组里面存放所有的书。

2.再建立一个包Operation 这个类里面有一个OI接口，通过对接口里面的Work方法重写，来实现管理员身份和普通用户身份的不同操作。

3.最后建立一个User包，里面有三个类，User，Admin,NormalUser

Admin和NormalUser都继承自User.User里秒你有一个数组protected IO[] operation;这个数组里面包含了用户或者管理员所具备的操作。通过对数组的索引来确定具体需要调用的操作方法。

下面来看看代码吧：

book包

Book类

package book_manager.book;public class Book { private String name; private String id; private String author; private int price; private String type; private boolean isBorrow; public Book(String name, String id, String author, int price,  String type, boolean isBorrow) { this.name = name; this.id = id; this.author = author; this.price = price; this.type = type; this.isBorrow = isBorrow; } @Override //Object中内置的类，用来格式化打印book的信息 public String toString() { return "Book{" +  "name='" + name + '\'' +  ", id='" + id + '\'' +  ", author='" + author + '\'' +  ", price=" + price +  ", type='" + type + '\'' +  ", isBorrow=" + isBorrow +  '}'; } public String getName(){ return name; } public boolean isBorrow(){ return isBorrow; } public void setBorrow(boolean bool){ this.isBorrow=bool; } public String getId(){ return id; }}

BookList类

package book_manager.book;import java.util.Arrays;public class BookList {  private Book[] books = new Book[100];  private int size;  public BookList(){  books[0] = new Book("金瓶梅",    "001", "兰陵笑笑生", 100,    "古典名著", false);  books[1] = new Book("水浒传",    "002", "施耐庵", 100,    "古典名著", false);  books[2] = new Book("西游记",    "003", "吴承恩", 100,    "古典名著", false);  size = 3; } public int getSize(){   return size; } public void setBooks(int index,Book book){   books[index]=book; } public void setSize(int size){   this.size=size; } public Book getBook(int index){   return books[index]; }}

Operation包：

ADD类

package book_manager.Operation;import book_manager.book.*;import java.util.Scanner;public class ADD implements IO{ @Override public void work(BookList bookList) {  Scanner scanner = new Scanner(System.in);  System.out.println("请输入书名");  String name =scanner.next();  System.out.println("请输入序号");  String id = scanner.next();  System.out.println("请输入作者");  String author =scanner.next();  System.out.println("请输入价格");  int price = scanner.nextInt();  System.out.println("请输入类型");  String type = scanner.next();  Book book = new Book(name, id,    author, price, type, false);  bookList.setBooks(bookList.getSize(),book);  bookList.setSize(bookList.getSize()+1);  System.out.println("添加成功"); }}

Borrow类

package book_manager.Operation;import book_manager.book.Book;import book_manager.book.BookList;import java.util.Scanner;public class Borrow implements IO{ @Override public void work(BookList bookList) {  int i=0;  int flag=0;  Scanner scan = new Scanner(System.in);  System.out.println("请输入需要借阅的书名");  String name = scan.next();  for(;i

Delete类

package book_manager.Operation;import book_manager.book.BookList;import java.util.Scanner;public class Delete implements IO{ public void work(BookList bookList){  Scanner scanner = new Scanner(System.in);  System.out.println("请输入想要删除的编号");  String id = scanner.next();  for(int i=0;i

Exit类

package book_manager.Operation;import book_manager.book.BookList;public class Exit implements IO{ @Override public void work(BookList bookList) {  System.out.println("退出成功");  System.exit(0); }}

Find类

package book_manager.Operation;import book_manager.book.BookList;import java.util.Scanner;public class Find implements IO{ @Override public void work(BookList bookList) {  int i=0;  int count=0;  Scanner scan = new Scanner(System.in);  System.out.println("请输入需要查找的书名");  String name = scan.next();  for(;i

IO接口

package book_manager.Operation;import book_manager.book.BookList;public interface IO { abstract public void work(BookList bookList);}

PrintAll类

package book_manager.Operation;import book_manager.book.BookList;public class PrintAll implements IO{ @Override public void work(BookList bookList) {  for(int i=0;i

Return类

package book_manager.Operation;import book_manager.book.BookList;import java.util.Scanner;public class Return implements IO{ @Override public void work(BookList bookList) {  int i=0;  int flag=0;  Scanner scan = new Scanner(System.in);  System.out.println("请输入需要归还的ID");  String id = scan.next();  for(;i

user包:

User类

package book_manager.user;import book_manager.Operation.*;import book_manager.Operation.IO;import book_manager.book.BookList;abstract public class User { String name; protected IO[] operation; public User(String name){  this.name=name; } abstract public int menu();//该方法被重写 public void doOperation(int choice, BookList bookList) {  operation[choice].work(bookList); }}

Admin类

package book_manager.user;import book_manager.Operation.*;import java.util.Scanner;public class Admin extends User{ public Admin(String name){  super(name);  operation=new IO[]{    new Exit(),    new Find(),    new ADD(),    new Delete(),    new PrintAll(),  }; } public int menu() {  System.out.println("============");  System.out.println("hello " + name);  System.out.println("1. 查找书籍");  System.out.println("2. 增加书籍");  System.out.println("3. 删除书籍");  System.out.println("4. 打印所有信息");  System.out.println("0. 退出");  System.out.println("============");  System.out.println("请输入您的选择: ");  Scanner scanner = new Scanner(System.in);  int choice = scanner.nextInt();  return choice; } }

NormalUser

package book_manager.user;import book_manager.Operation.*;import java.util.Scanner;public class NormalUser extends User{ public NormalUser(String name){  super(name);  operation=new IO[]{    new Exit(),    new Find(),    new Borrow(),    new Return(),    new PrintAll()  }; } public int menu() {  System.out.println("============");  System.out.println("hello " + name);  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("4. 查看全部书籍");  System.out.println("0. 退出");  System.out.println("============");  System.out.println("请输入您的选择: ");  Scanner scanner = new Scanner(System.in);  int choice = scanner.nextInt();  // close 本质上是在关闭 System.in  // 由于后面还需要用到 System.in, 此处不能盲目关闭.  // scanner.close();  return choice; }}

最后还有一个Test类，里面放了main函数

package book_manager;import book_manager.book.BookList;import book_manager.user.Admin;import book_manager.user.NormalUser;import book_manager.user.User;import java.util.Scanner;public class Test { public static void main(String[] args) {  BookList list = new BookList();  User user = login();  //通过不同的choice和身份调用不同的Operation方法   while(true){   int choice = user.menu();   user.doOperation(choice, list);  } } public static User login(){  Scanner scanner = new Scanner(System.in);  System.out.println("请输入你的姓名");  String name = scanner.next();  System.out.println("请输入你的身份");  System.out.println("1.普通用户 2.管理员");  int role= scanner.nextInt();  if(role==1){   return new NormalUser(name);  }  else{   return new Admin(name);  } }}