1.简介
通过前面知识:类,抽象类,封装,继承,多态,接口的学习,这篇文章将会通过对学习的知识点的整合运用,写一个小项目——图书管理系统,来帮助大家更好的掌握前面学习的知识点。
2.设计需求
-
根据用户信息进行登录(选择身份)
-
管理员身份
- 查找图书
- 新增图书
- 删除图书
- 显示图书
- 退出系统
- 普通用户身份
- 查找图书
- 借阅图书
- 归还图书
- 退出系统
3.相关类的设计
根据设计需求,我们分析所需要的类.
-
首先是图书类 -> 先创建 package book包 -> 创建 Book 类, 表示一本书,创建 BookList 类, 用来保存 N 本书.
-
接着是操作类 ->先创建 package operation包 -> 根据功能创建操作类
AddOperation -> 新增图书 BrowOperation -> 借阅图书 DelOperation -> 删除图书 ExitOperation -> 退出系统 FindOperation -> 查找图书 ReturnOperation -> 归还图书 ShowOperation -> 显示图书
根据操作类来设计一个接口IOPeration。
-
然后创建用户类 -> 先创建 package user包 -> 创建 User 类, 这是一个抽象类,创建普通用户类, 是 User 的子类创建管理员用户类。
-
最后创建测试类Main 来测试下代码的基本框架是否存在问题。
4.图书类
1.Book类
package book;
/**
* Created with IntelliJ IDEA.
* Description:书籍信息
* User: 28144
* Date: 2022-11-27
* Time: 18:59
*/
public class Book {
private String name;//名字
private String author;//作者
private int price;//价格
private String type;//类型
private boolean isBorrowed;//是否被借出
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 double 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 isBorrowed() {
return isBorrowed;
}
public void setBorrowed(boolean borrowed) {
isBorrowed = borrowed;
}
@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
", type='" + type +
(isBorrowed == true ? " 已近被借出" : " 未被借出")
+ '}';
}
}
2. BookList类
package book;
/**
* Created with IntelliJ IDEA.
* Description:书架
* User: 28144
* Date: 2022-11-27
* Time: 19:06
*/
public class BookList {
private Book[] books = new Book[10];
private int usedSize;//来记录当前books数组当中有多少本书
public BookList() {
books[0] = new Book("三国演义","罗贯中",89,"小说");
books[1] = new Book("西游记","吴承恩",59,"小说");
books[2] = new Book("红楼梦","曹雪芹",189,"小说");
this.usedSize = 3;
}
public Book getBook(int pos) {
return this.books[pos];
}
public void setBook(Book book) {
this.books[usedSize] = book;
}
public void setBook(int pos,Book book) {
this.books[pos] = book;
}
public int getUsedSize() {
return usedSize;
}
public void setUsedSize(int usedSize) {
this.usedSize = usedSize;
}
}
5.操作类
操作的接口:
package opera;
import book.BookList;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:16
*/
public interface IOPeration {
void work(BookList bookList);
}
1.新增图书
package opera;
import book.Book;
import book.BookList;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:18
*/
public class AddOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("新增图书!");
Scanner scanner = new Scanner(System.in);
System.out.println("输入书名:");
String name = scanner.nextLine();
System.out.println("输入作者:");
String author = scanner.nextLine();
System.out.println("请输入类型:");
String type = scanner.nextLine();
System.out.println("输入价格:");
int price = scanner.nextInt();
Book book = new Book(name,author,price,type);
int currentSize = bookList.getUsedSize();
for (int i = 0; i < currentSize; i++) {
Book tmp = bookList.getBook(i);
if(tmp.getName().equals(name)) {
System.out.println("这本书已经存在,不能再放入!");
return;
}
}
bookList.setBook(book);
//修改usedSize
bookList.setUsedSize(currentSize + 1);
}
}
2.借阅图书
package opera;
import book.Book;
import book.BookList;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:25
*/
public class BrowOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("借阅图书!");
System.out.println("输入你要借阅的图书:");
Scanner scanner = new Scanner(System.in);
String name = scanner.nextLine();
int currentSize = bookList.getUsedSize();
for (int i = 0; i < currentSize; i++) {
Book book = bookList.getBook(i);
if(book.getName().equals(name) && !book.isBorrowed()) {
book.setBorrowed(true);
System.out.println("借阅成功!");
return;
}
}
System.out.println("借阅失败!");
}
}
3.删除图书
package opera;
import book.Book;
import book.BookList;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:21
*/
public class DelOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("删除图书!");
System.out.println("请输入你要删除图书的名字:");
Scanner scanner = new Scanner(System.in);
String name = scanner.nextLine();
int currentSize = bookList.getUsedSize();
int index = -1;
for (int i = 0; i < currentSize; i++) {
Book tmp = bookList.getBook(i);
if(tmp.getName().equals(name)) {
index = i;
break;
}
}
//挪动数据
for (int j = index; j < currentSize - 1; j++) {
Book book = bookList.getBook(j + 1);
bookList.setBook(j,book);
}
//修改Size
bookList.setUsedSize(currentSize - 1);
//因为删除的是对象,所以把最后一个置为null
bookList.setBook(currentSize - 1,null);
System.out.println("删除成功!");
}
}
4.查找图书
package opera;
import book.Book;
import book.BookList;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:20
*/
public class FindOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("查找图书!");
System.out.println("请输入你要查找的图书的名字:");
Scanner sc = new Scanner(System.in);
String name = sc.nextLine();
int currentSize = bookList.getUsedSize();
for (int i = 0; i < currentSize; i++) {
Book book = bookList.getBook(i);
if(book.getName().equals(name)) {
System.out.println("找到了这本书");
System.out.println(book);
return;
}
}
System.out.println("没有这本书!");
}
}
5.归还图书
package opera;
import book.Book;
import book.BookList;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:25
*/
public class ReturnOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("归还图书!");
System.out.println("输入你要归还的图书:");
Scanner scanner = new Scanner(System.in);
String name = scanner.nextLine();
int currentSize = bookList.getUsedSize();
for (int i = 0; i < currentSize; i++) {
Book book = bookList.getBook(i);
if (book.getName().equals(name) && book.isBorrowed()) {
book.setBorrowed(false);
System.out.println("归还成功!");
return;
}
}
System.out.println("归还失败!");
}
}
6.显示图书
package opera;
import book.Book;
import book.BookList;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:22
*/
public class ShowOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("打印所有图书!");
int currentSize = bookList.getUsedSize();
for (int i = 0; i < currentSize; i++) {
Book book = bookList.getBook(i);
System.out.println(book);
}
}
}
7.退出系统
package opera;
import book.BookList;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:24
*/
public class ExitOperation implements IOPeration{
@Override
public void work(BookList bookList) {
System.out.println("退出系统!");
System.exit(0);
}
}
6.用户类
1.User类
创建 User类, 这是一个抽象类
package user;
import book.BookList;
import opera.IOPeration;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:12
*/
public abstract class User {
protected String name;
protected IOPeration[] ioPerations;
public User(String name) {
this.name = name;
}
public abstract int menu();
public void dowork(int choice, BookList bookList) {
this.ioPerations[choice].work(bookList);
}
}
2.普通用户类
创建普通用户类, 是 User 的子类.
package user;
import opera.*;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:14
*/
public class NormalUser extends User{
public NormalUser(String name) {
super(name);
this.ioPerations = new IOPeration[] {
new ExitOperation(),
new FindOperation(),
new BrowOperation(),
new ReturnOperation(),
};
}
public int menu() {
System.out.println("********************************");
System.out.println("hello " + name + " 欢迎来到图书小练习");
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("请输入你的操作:");
Scanner scanner = new Scanner(System.in);
int choice = scanner.nextInt();
return choice;
}
}
3.管理员类
创建管理员用户类.
package user;
import opera.*;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:13
*/
public class AdminUser extends User {
public AdminUser(String name) {
super(name);
this.ioPerations = new IOPeration[] {
new ExitOperation(),
new FindOperation(),
new AddOperation(),
new DelOperation(),
new ShowOperation(),
};
}
public int menu() {
System.out.println("********************************");
System.out.println("hello " + name + " 欢迎来到图书小练习");
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("请输入你的操作:");
Scanner scanner = new Scanner(System.in);
int choice = scanner.nextInt();
return choice;
}
}
7.测试类
import book.Book;
import book.BookList;
import user.AdminUser;
import user.NormalUser;
import user.User;
import java.util.Scanner;
/**
* Created with IntelliJ IDEA.
* Description:
* User: 28144
* Date: 2022-11-27
* Time: 19:32
*/
public class Main {
public static User login() {
System.out.println("请输入你的姓名:");
Scanner scanner = new Scanner(System.in);
String name = scanner.nextLine();
System.out.println("请输入你的身份:1->管理员 0->普通用户");
int choice = scanner.nextInt();
if(choice == 1) {
return new AdminUser(name);
}else {
return new NormalUser(name);
}
}
public static void main(String[] args) {
BookList bookList = new BookList();
User user = login();
while (true) {
int choice = user.menu();
//根据choice和user来确定调用那个对象的那个操作。
user.dowork(choice, bookList);
}
}
}