分层情况

实体类Book代码 

//实体类
public class Book {private int id;private String name;private int bsum;public Book() {}public Book(int id, String name, int bsum) {this.id = id;this.name = name;this.bsum = bsum;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getBsum() {return bsum;}public void setBsum(int bsum) {this.bsum = bsum;}@Overridepublic String toString() {return "Book{" +"id=" + id +", name='" + name + '\'' +", bsum=" + bsum +'}';}
}

控制层BookController代码

import com.xszx.beans.Book;
import com.xszx.service.BookService;
import com.xszx.service.impl.BookServiceImpl;import java.util.List;
import java.util.Scanner;//控制层  控制请求转发
public class BookController {Scanner sc=new Scanner(System.in);BookService bookService = new BookServiceImpl();//主方法public void menu(){System.out.println();System.out.println("                     ---小张图书管理系统---                          ");System.out.println("***【1】查看图书列表 【2】添加图书 【3】修改图书 【4】删除图书 【0】退出系统***");System.out.println("请选择您要进行的操作：");int n = sc.nextInt();if(n==1){checkBook();menu();}else if (n==2){addBook();menu();}else if(n==3){alterBook();menu();}else if (n==4){deleteBook();menu();}else if(n==0){System.out.println("系统已退出，欢迎下次使用！！！");System.exit(0);}}//删除图书private void deleteBook() {Book book = new Book();System.out.println("请输入您要删除的图书名称:");book.setName(sc.next());//判断名字是否存在 存在则删除 不存在则提示不存在boolean b=bookService.getbookname(book);if(b){bookService.deleteBook(book);System.out.println("删除成功！");} else{System.out.println("您要删除的图书不存在！");menu();}}//修改图书private void alterBook() {Book book = new Book();System.out.println("请输入您要修改的图书名称:");book.setName(sc.next());//判断名字是否存在 存在则继续修改 不存在则提示不存在boolean b=bookService.getbookname(book);if(b){Book book1 = new Book();System.out.println("请输入修改后的图书名称:");book1.setName(sc.next());System.out.println("请输入修改后的图书库存:");book1.setBsum(sc.nextInt());bookService.alterBook(book,book1);System.out.println("修改成功！");} else{System.out.println("您要修改的图书不存在！");menu();}}//增加图书private void addBook() {Book book = new Book();System.out.println("请输入您要添加的图书名称:");book.setName(sc.next());//判断名字是否存在 存在则提示名字冲突 不存在则继续执行boolean b=bookService.getbookname(book);if(b){System.out.println("添加的图书名字冲突");menu();}else{System.out.println("请输入您要添加的图书库存:");book.setBsum(sc.nextInt());//后台添加完成，是否成功int i = bookService.addbook(book);if (i==1){System.out.println("添加成功！！！");menu();}else{System.out.println("添加失败！！！");menu();}}}//查看图书private void checkBook() {List<Book> list = bookService.getbook();for (Book book : list){System.out.println(book);}menu();}
}

数据层BookDao代码

import com.xszx.beans.Book;import java.util.ArrayList;
import java.util.List;//数据层   连接数据库  处理数据  写sql   后期为接口
public class BookDao {static List<Book> blist=new ArrayList<>();static{blist.add(new Book(1,"三国",666));blist.add(new Book(2,"水浒",888));blist.add(new Book(3,"红楼梦",999));blist.add(new Book(4,"西游记",222));blist.add(new Book(5,"宝莲灯",333));}public List<Book> getbooks() {return blist;}public int addbook(Book book) {int id = blist.get(0).getId();//查找最大值for (Book bk : blist){if (id<bk.getId()){id=bk.getId();}}book.setId(id+1);blist.add(book);return 1;}//判断名字是否存在public boolean getbookname(Book book) {for (Book bk : blist){if(bk.getName().equals(book.getName())){return true;}}return false;}public void alterBook(Book book, Book book1) {for (Book bk : blist){//修改参数if(bk.getName().equals(book.getName())){bk.setName(book1.getName());bk.setBsum(book1.getBsum());}}}public void deleteBook(Book book) {for (Book bk : blist){//删除元素if(bk.getName().equals(book.getName())){blist.remove(bk);break;}}}
}

 业务层接口BookService代码

import com.xszx.beans.Book;import java.util.List;//业务层  处理业务
public interface BookService {List<Book> getbook();int addbook(Book book);boolean getbookname(Book book);void alterBook(Book book, Book book1);void deleteBook(Book book);
}

 业务层实现类BookServiceImpl代码

import com.xszx.beans.Book;
import com.xszx.dao.BookDao;
import com.xszx.service.BookService;import java.util.List;public class BookServiceImpl implements BookService {BookDao bookDao = new BookDao();@Overridepublic List<Book> getbook() {return bookDao.getbooks();}@Overridepublic int addbook(Book book) {return bookDao.addbook(book);}@Overridepublic boolean getbookname(Book book) {return bookDao.getbookname(book);}@Overridepublic void alterBook(Book book, Book book1) {bookDao.alterBook(book, book1);}@Overridepublic void deleteBook(Book book) {bookDao.deleteBook(book);}
}

测试类Test代码 

import com.xszx.controller.UserController;//测试类
public class Test {public static void main(String[] args) {System.out.println("欢迎来到小张图书管理系统！！！");new UserController().menu();}
}