java--demo之图书馆管理系统

思路：创建三各类  books 相当于书类 记录着书的属性和获取书的方法      mannagerbooks 管理图书 里面创建的一个books类型的数组  相当于书架   里面实现增删改查的方法     TestBooks 测试类记录着调各个类的方法实现菜单。

package com.hainiu.book;

import java.util.Scanner;

//书的属性类
class Books{
    
    private String name;
    private double price;
    private int number;
    
    public Books(){        
    }
    public Books(String name, double price, int number) {
        this.name = name;
        this.price = price;
        this.number = number;
    
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public int getNumber() {
        return number;
    }
    public void setNumber(int number) {
        this.number = number;
    }
    public String show(){
        return name +","+ price + "," + number;
    }
}
class ManagerBooks{
    //创建一个数组 相当于书架存放book
    private Books [] books = new Books[100];
    //添加
    public void add(Books book){
        //循环查看书架  如果没有这本书 那么增加 如果有那么提示已经有这本书了        
        for (int i = 0; i < books.length; i++) {
            if(books[i]==null){
                books[i]=book;
                System.out.println("添加成功");
                break;
            }else{
                System.out.println("该书已存在");
            }        
        }
        }
    //修改
    public void update(int number,double price){
        //循环查看书架  如果有这本书 那么修改 如果没有提示没有这本书
        for (int i = 0; i < books.length; i++) {
            if(books[i].getNumber()==number){
                //如果有这个编号 那么改他的价格
                books[i].setPrice(price);
                System.out.println("修改成功");
            }else{
                System.out.println("该书不存在");
            }
            break;
        }
    }
    //删除 
    public void delete(int number){
        for (int i = 0; i < books.length; i++) {
            if(books[i].getNumber()==number){
                //数组删除用后一个覆盖前一个
                for (int j = i; j < books.length-1; j++) {
                    books[j]=books[j+1];
                }
                if(books[books.length-1]!=null){
                    books[books.length-1]=null;
                }
                System.out.println("删除成功");
                break;
            }
        }
    }
    //查询
    public void query(){
        System.out.println("图书编号\t图书名称 \t图书价格");
        for (Books b : books) {
            if(b == null){
                break;
            }
            System.out.println(b.show());
        }        
    }
    //退出
    
    }
public class TestBooks {
    public void startsystem(){
        Scanner sc = new Scanner(System.in);
        ManagerBooks mgb = new ManagerBooks();
        System.out.println("-----欢迎来到菜单-----");
        System.out.println("1、添加    2、修改     3、删除     4、查询   5、退出");
        int number;
        String name;
        double price;
        while(true){
            System.out.println("请选择菜单");
            //录入数字的
            int n =sc.nextInt();            
            switch(n){
            //如果是1 那么就是添加   name +","+ price + "," + number;
                case 1:
                    System.out.println("欢迎来到添加页面");
                    System.out.println("请输入编号");
                     number = sc.nextInt();
                    System.out.println("请输入书名");
                     name = sc.next();
                    System.out.println("请输入价格");
                     price = sc.nextDouble();
                    Books books = new Books( name,  price,  number);
                    mgb.add(books);
                    break;
            //如果是2那么就是修改页面
                case 2:
                    System.out.println("欢迎来到修改页面");
                    System.out.println("输入要修改的编号");
                    number = sc.nextInt();
                    System.out.println("输入改的价格");
                    price = sc.nextDouble();
                    mgb.update(number, price);
                    break;
                case 3:
                    System.out.println("欢迎来到删除页面");
                    System.out.println("输入要删除的编号");
                    number = sc.nextInt();
                    mgb.delete(number);
                    break;
                case 4:
                    System.out.println("欢迎来到查询页面");
                    mgb.query();
                    break;
                case 5:
                    System.out.println("退出页面");
                    System.exit(0);
                    
            }
            }
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        new TestBooks().startsystem();
    }

}