五分钟”手撕“图书管理系统

前言：

图书馆管理系统需要结合JavaSE的绝大部分知识，是一个很好的训练项目。

为了让大家更加方便的查阅与学习，我把代码放开头，供大家查询。

还有对代码的分析，我将以类为单位分开讲解。

目录

全部代码 

Main类 

User类 

BookList类 

Book类 

NormalUser类 

---

 

全部代码 

/*一共有三个包*///User包
//User.java
package user;
import Book.BookList;
import Operation.IOparetion;public abstract class User {protected String name;protected IOparetion[] iOparetions;public User(String name) {this.name = name;}public abstract int menu();public void doIOparetion(int chioce, BookList bookList){this.iOparetions[chioce].work(bookList);}
}//User包
//NormalUser.java
package user;
import Operation.*;
import java.util.Scanner;public class NormalUser extends User{public NormalUser(String name) {super(name);this.iOparetions= new IOparetion[] {new ExitOparetion(),new FindOparetion(),new BorrowedOparetion(),new ReturnOparetion()};}@Overridepublic int menu() {System.out.println("******管理员用户******");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("请输入数字：");Scanner scanner=new Scanner(System.in);int choice= scanner.nextInt();return choice;}
}//User包
//Administrators.java
package user;
import Operation.*;
import java.util.Scanner;public class Administrators extends User {public Administrators(String name) {super(name);this.iOparetions = new IOparetion[]{new ExitOparetion(),new FindOparetion(),new AddOparetion(),new DelOparetion(),new ShowOparetion()};}public int menu() {System.out.println("******普通用户******");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("请输入数字：");Scanner scanner = new Scanner(System.in);int choice = scanner.nextInt();return choice;}
}//Book包
//Book.java
package Book;public class Book {private String name;private String author;private int price;private String type;private boolean isLend;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 isLend() {return isLend;}public void setLend(boolean lend) {isLend = lend;}@Overridepublic String toString() {return "Book{" +"name='" + name + '\'' +", author='" + author + '\'' +", price=" + price +", type='" + type + '\'' +(isLend==true?"已借出":"未借出")+'}';}
}//Book包
//BookList.java
package Book;public class BookList {private Book[] book=new Book[10];private int usedSize;public Book getBook(int pos) {return book[pos];}public void setBook(int pos,Book book) {this.book[pos] = book;}public int getUsedSize() {return usedSize;}public void setUsedSize(int usedSize) {this.usedSize = usedSize;}public BookList() {book[0]=new Book("西游记","吴承恩",19,"小说");book[1]=new Book("三国演义","罗贯中",36,"小说");book[2]=new Book("红楼梦","曹雪芹",13,"小说");this.usedSize=3;}public boolean isFull(){if(usedSize==book.length){return true;}return false;}
}//Oparetion包
//Ioparetion.java
package Operation;import Book.BookList;public interface IOparetion {void work(BookList bookList);
}//Oparetion包
//AddOparetion.java
package Operation;import Book.Book;
import Book.BookList;
import java.util.Scanner;public class AddOparetion implements IOparetion {@Overridepublic void work(BookList bookList) {Scanner scanner=new Scanner(System.in);System.out.println("请输入你要添加的书籍名字");String name=scanner.nextLine();System.out.println("请输入作者的名字");String author=scanner.nextLine();System.out.println("请输入书的种类");String type=scanner.nextLine();System.out.println("请输入书的价格");int price=scanner.nextInt();Book book=new Book(name,author,price,type);if(bookList.isFull()){System.out.println("书架满了，借阅失败");return;}bookList.setBook(bookList.getUsedSize(), book);bookList.setUsedSize(bookList.getUsedSize()+1);System.out.println("添加成功");}
}//Oparetion包
//BorrowedOparetion.java
package Operation;import Book.BookList;
import java.util.Scanner;public class BorrowedOparetion implements IOparetion{@Overridepublic void work(BookList bookList) {System.out.println("请输入你要找的书名");Scanner scanner=new Scanner(System.in);String name=scanner.nextLine();for(int i=0;i<bookList.getUsedSize();i++){if(name.equals(bookList.getBook(i).getName())){bookList.getBook(i).setLend(true);System.out.println("借阅成功");return;}}System.out.println("借阅失败");}}//Oparetion包
//DelOparetion.java
package Operation;import Book.BookList;
import java.util.Scanner;public class DelOparetion implements IOparetion{@Overridepublic void work(BookList bookList) {System.out.println("请输入你要删除的书籍名字");Scanner scanner=new Scanner(System.in);String s=scanner.nextLine();int pos=-1;int i=0;for (;i<bookList.getUsedSize();i++){if(s.equals(bookList.getBook(i))){pos=i;}if(i>=bookList.getUsedSize()){System.out.println("没有你要找的书");return;}}for(int j=i;i<bookList.getUsedSize()-1;i++){bookList.setBook(j,bookList.getBook(j+1));}bookList.setBook(bookList.getUsedSize(), null);bookList.setUsedSize(bookList.getUsedSize()-1);System.out.println("删除成功");}
}//Oparetion包
//ExitOparetion.java
package Operation;
import Book.BookList;public class ExitOparetion implements IOparetion {@Overridepublic void work(BookList bookList) {System.out.println("退出系统中....");for(int i=0;i<bookList.getUsedSize()-1;i++){bookList.setBook(i,null);}System.exit(0);}
}//Oparetion包
//FindOparetion.java
package Operation;import Book.BookList;
import java.util.Scanner;public class FindOparetion implements IOparetion{@Overridepublic void work(BookList bookList) {System.out.println("请输入你要找的书名");Scanner scanner=new Scanner(System.in);String name=scanner.nextLine();for(int i=0;i<bookList.getUsedSize();i++){if(name.equals(bookList.getBook(i).getName())){System.out.println("找到了，下标为："+i);System.out.println(bookList.getBook(i));return;}}System.out.println("没找到");}
}//Oparetion包
//ReturnOparetion.java
package Operation;import Book.BookList;
import java.util.Scanner;public class ReturnOparetion implements IOparetion{@Overridepublic void work(BookList bookList) {Scanner scanner=new Scanner(System.in);System.out.println("请输入你要归还的书名");String s=scanner.nextLine();for (int i = 0; i < bookList.getUsedSize()-1; i++) {if(s.equals(bookList.getBook(i).getName())){bookList.getBook(i).setLend(false);System.out.println("归还成功");return;}}System.out.println("归还失败，没有你要归还的书");}
}//Oparetion包
//ShowOparetion.java
package Operation;
import Book.BookList;public class ShowOparetion implements IOparetion{@Overridepublic void work(BookList bookList) {for(int i=0;i<bookList.getUsedSize();i++){System.out.println(bookList.getBook(i));}}}

 首先，我们需要打个框架出来，由于java是一门面向对象的编程，所以我们应该要多考虑对象，而不是过程。

我将它分为三个包：User、Book、operation包，其实对象有：书架、书、用户、管理员。

总体请看下图：

 

这里我主要讲解大致结构和细微的细节 ，因为方法的思路在数据结构讲解更加清晰

Main类 

public class Main {public static User login(){Scanner scanner=new Scanner(System.in);System.out.println("请输入你的名字");String name=scanner.nextLine();System.out.println("请输入你的身份：1.普通用户  2.管理员用户");int choice =scanner.nextInt();if(choice==1){NormalUser normalUser=new NormalUser(name);return normalUser;}else{Administrators administrators=new Administrators(name);return administrators;}}public static void main(String[] args) {BookList bookList=new BookList();User user=login();while (true){int ret=user.menu();user.doIOparetion(ret,bookList);}}
}

 上述代码中：

Scanner来new一个对象来输入，int一个choice来接收选1还是2，选择是管理人还是普通用户。

由于要返回一个对象，所以login的返回值是user类型的，user与管理员和普通用户是父子关系，在main中用user类型接收，属于向上转型（好处就是发生多态）。

User类 

package user;
import Book.BookList;
import Operation.IOparetion;public abstract class User {protected String name;protected IOparetion[] iOparetions;public User(String name) {this.name = name;}public abstract int menu();public void doIOparetion(int chioce, BookList bookList){this.iOparetions[chioce].work(bookList);}
}

 上述代码中：

User作为父类，被管理员和普通用户继承，被abstract修饰主要是为了menu这个方法被继承，实现多态。

IOparetion是一个接口，是为了被那些add和del等等方法实现的，还是实现多态，

它现在作为一个数组来接收，是为了存放这些方法，这样就不用一个个在用户或者管理员里面书写了，可以直接定义为一个类（这也是为什么方法可以另外书写的原因），这体现了面向对象的特点，大大缩短了工程量和分模块的简洁性（即使下次有人需要用，不需要再写，直接调用就好了）。

BookList类 

package Book;public class BookList {private Book[] book=new Book[10];private int usedSize;public Book getBook(int pos) {return book[pos];}public void setBook(int pos,Book book) {this.book[pos] = book;}public int getUsedSize() {return usedSize;}public void setUsedSize(int usedSize) {this.usedSize = usedSize;}public BookList() {book[0]=new Book("西游记","吴承恩",19,"小说");book[1]=new Book("三国演义","罗贯中",36,"小说");book[2]=new Book("红楼梦","曹雪芹",13,"小说");this.usedSize=3;}public boolean isFull(){if(usedSize==book.length){return true;}return false;}
}

 对于上述代码：

由于java是面向对象编程，所以对于一些信息不需要用户来知道内部是怎么实现的，所以用private修饰，这样的话需要set和get方法来获取，这样之后的代码都需要调用set和get来获取或者是赋值。

BookList是书架，所以里面是摆书的，所以用Book类型作为数组，来收取book。可以放很多本。

usedsize是有效书籍数，就是记录里面有多少本。

Book类 

package Book;public class Book {private String name;private String author;private int price;private String type;private boolean isLend;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 isLend() {return isLend;}public void setLend(boolean lend) {isLend = lend;}@Overridepublic String toString() {return "Book{" +"name='" + name + '\'' +", author='" + author + '\'' +", price=" + price +", type='" + type + '\'' +(isLend==true?"已借出":"未借出")+'}';}
}

对于上述代码：

Book是类，它代表的是一本书，所以你需要定义名字作者价格什么什么的。

也是利用封装，只把必要的信息给用户，所以用privat密封起来，更加安全一点，所以需要set和get方法。

这里的toString方法里面有个三目操作符，如果isLend被借出的话，就是true，就会打印已借出，否则为借出。 

NormalUser类 

package user;
import Operation.*;
import java.util.Scanner;public class NormalUser extends User{public NormalUser(String name) {super(name);this.iOparetions= new IOparetion[] {new ExitOparetion(),new FindOparetion(),new BorrowedOparetion(),new ReturnOparetion()};}@Overridepublic int menu() {System.out.println("******管理员用户******");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("请输入数字：");Scanner scanner=new Scanner(System.in);int choice= scanner.nextInt();return choice;}
}

对于上述代码：

如果继承了父类，使用构造方法时候需要先把父类的构造方法实现。

因为IOparetion是user里面的，user被普通用户继承，所以可以直接访问，把他变成一个数组，这样就可以存方法了，不用在这普通用户这个类里一个一个方法写，直接脱离出来，非常充分体现了面向对象的特点！