Java中利用面向对象写个简单的图书管理系统

在图书管理系统中，我们有三个事务，一个是管理员事务，一个是购物者事务，另一个是存储图书事务，这三个事务可以写成三个class类。

导入我们需要的模块：

import java.util.*; import java.util.Scanner;

首先是我们的存储类。存储类需要四个变量：增加变量、减少变量、总变量和初始变量：

class kucun{     //增变量         int bok,shu,qbii;         //总变量         int bkzon,shuzon,qbzon;         //减变量         int bokj,shuj,qbj;         //名称         char bk = '书';         char sb = '包';         char qb = '铅';         ///初始变量         int book = 10;         int shubao = 10;         int qbi = 10; }

二是我们的管理员(需要继承我们的变量):

class guanli extends kucun {     public void yu() {         String tui;         Scanner sc=new Scanner(System.in);         System.out.println("成功进入管理员");         while (true){             System.out.println("继续请按5，退出请按4");             ///键盘接收数据             tui =sc.nextLine();             if (tui.equals("4")) {                 //如果是，提示退出输入                 System.out.println("退出系统！");                 break;             }else {                 System.out.println("请输入您需要选择的内容 1.增加库存 2.减少库存 3.查询库存 4.退出系统");                 Scanner oneo = new Scanner(System.in);                 int on1 = oneo.nextInt();                 switch (on1) {                     case 1:                         System.out.println("请输入您需要添加的库存1."   bk   " 2."   sb   " 3."   qb);                         Scanner nq = new Scanner(System.in);                         int nq1 = nq.nextInt();                         switch (nq1) {                             case 1:                                 System.out.println("输入您需要添加的库存：");                                 Scanner oneon = new Scanner(System.in);                                 bok = oneon.nextInt();                                 bkzon = book   bok;                                 System.out.println("添加了书"   bok   "本书的总库存为："   bkzon);                                 break;                             case 2:                                 System.out.println("输入您需要添加的库存：");                                 Scanner one = new Scanner(System.in);                                 shu = one.nextInt();                                 shuzon = shubao   shu;                                 System.out.println("添加了包"   shu   "本包总库存为："   shuzon);                                 break;                             case 3:                                 System.out.println("输入您需要添加的库存：");                                 Scanner on = new Scanner(System.in);                                 qbii = on.nextInt();                                 qbzon = qbi   qbii;                                 System.out.println("添加了书"   qbii   "本书的总库存为："   qbzon);                                 break;                         }                         break;                     case 2:                         System.out.println("请输入您需要减少的库存1."   bk   " 2."   sb   " 3."   qb);                         Scanner n = new Scanner(System.in);                         int n1 = n.nextInt();                         switch (n1) {                             case 1:                                 System.out.println("输入您需要减少的库存：");                                 Scanner oneon = new Scanner(System.in);                                 bokj = oneon.nextInt();                                 book = bkzon - bokj;                                 System.out.println("减少了书"   bok   "本书的总库存为："   book);                                 break;                             case 2:                                 System.out.println("输入您需要减少的库存：");                                 Scanner one = new Scanner(System.in);                                 shuj = one.nextInt();                                 shubao = shuzon - shuj;                                 System.out.println("减少了包"   shuj   "本包总库存为："   shubao);                                 break;                             case 3:                                 System.out.println("输入您需要减少的库存：");                                 Scanner on = new Scanner(System.in);                                 qbj = on.nextInt();                                 qbi = qbzon - qbj;                                 System.out.println("减少了书"   qbii   "本书的总库存为："   qbi);                                 break;                          }                         break;                     case 3:                         int chabk = book   bok - bokj;                         int chasz = shubao   shu - shuj;                         int chaqb = qbi   qbii - qbj;                         System.out.println("查询后的库存1."   bk   "剩余："   chabk   "2."   sb   "剩余："   chasz   "3."   qb   "剩余："   chaqb);                         break;                 }             }             }         }     } 

然后是我们的购物者:

class ygon extends kucun{
    public void yue(){
        String tui;
        Scanner sc=new Scanner(System.in);
        while (true){
            System.out.println("成功进入购物者系统");
            System.out.println("继续请按5，退出请按3");
            //键盘接收数据
            tui =sc.nextLine();
            if (tui.equals("3")) {
                //如果是，提示退出输入
                System.out.println("退出系统！");
                break;
            }else {
                System.out.println("请输入你需要选择的内容 1.购买商品 2.查询库存 3.退出系统");
                Scanner oneo = new Scanner(System.in);
                int on1 = oneo.nextInt();
                switch (on1) {
                    case 1:
                        System.out.println("请输入你需要购买什么的库存1." + bk + " 2." + sb + " 3." + qb);
                        Scanner n = new Scanner(System.in);
                        int n1 = n.nextInt();
                        switch (n1) {
                            case 1:
                                System.out.println("请输入你需要购买的数量:");
                                Scanner oneon = new Scanner(System.in);
                                bokj = oneon.nextInt();
                                bkzon = book - bokj;
                                System.out.println("减少了书" + bokj + "本书的总库存为：" + bkzon);
                                break;
                            case 2:
                                System.out.println("请输入你需要购买的数量:");
                                Scanner one = new Scanner(System.in);
                                shuj = one.nextInt();
                                shuzon = shubao - shuj;
                                System.out.println("减少了包" + shuj + "本包的总库存为：" + shuzon);
                                break;
                            case 3:
                                System.out.println("请输入你需要购买的数量:");
                                Scanner on = new Scanner(System.in);
                                qbj = on.nextInt();
                                qbzon = qbi - qbj;
                                System.out.println("减少了书" + qbj + "本书的总库存为：" + qbzon);
                                break;

                        }
                        break;
                    case 2:
                        int chabk = book - bokj;
                        int chasz = shubao - shuj;
                        int chaqb = qbi - qbj;
                        System.out.println("查询后的库存1." + bk + "剩余：" + chabk + "2." + sb + "剩余：" + chasz + "3." + qb + "剩余：" + chaqb);
                        break;
                }
            }
        }
    }
    }

这些类写完后，我们再加入我们的导语类：

class daoru{
    public void daoru(){
        System.out.println("欢迎进入管理系统");
        System.out.println("管理员进入请按1,购物者进入请按2");
    }
}

然后开始逐个调用我们的类：

public static void main(String[] arge){
        daoru dr = new daoru();
        dr.daoru();
        guanli gl = new guanli();
        ygon yg = new ygon();
        Scanner oneone=new Scanner(System.in);
        int one = oneone.nextInt();
        switch (one){
            case 1: gl.yu();
            break;
            case 2: yg.yue();
            break;
        }
    }

大功告成运行截图：

后续会更新对接数据库来进行数据存储，实现用户与管理员的交互，目前的此系统没有管理员和购物者的交互，只有个初始值交互，这个后续也会更新补上