我只提供思路,代码就不用了吧:先通过设备id找到模组,遍历模组,通过模组id删除中间表关系,再删除模组,最后删除设备(你应该用的是JDBC吧,用hibernate就简单多啦)
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public class Cart {
public StringBuilder data;
public float total;
public Cart(){
data=new StringBuilder();
}
public void buy(Goods g){
g.gtotal=g.gnum*g.gprice;
total=total+g.gtotal;
data.append("[");
data.append(g.gname+"|");
data.append(g.gprice+"|");
data.append(g.gnum+"|"); //还是竖线看着方便
data.append(g.gtotal);
data.append("]");
}
public void delete(Goods g){
int s=data.indexOf(g.gname);
int e=data.indexOf("]", s);
data.delete(s-1, e+1);
total=total-g.gtotal; //删除商品 ,需要修改总额
}
public void update(Goods g){
data.replace(3, 10, "["+g.gname+"|"+g.gprice+"|"+g.gnum+"|"+g.gtotal);
}
public void show(){
System.out.print("总计金额:" + total + " ") ;
System.out.println(data);
}
}
//Excute类里有点小错误,
//总觉得update方法 不对头,你想怎么做?
建一个静态的Map集合 做购物车的集合
key值 放商品的ID value 放 商品对象.
对map 增删改查就好了.. 结算完了 清空map
项目:完成一个电商系统的商品模块功能,商品类包含以下属性:商品ID, 商品名,类别名,单价,库存量,产地,计量单位等信息,要求实现商品管理功能以及管理员功能,具体如下:
1.管路员登录(账号密码固定admin/admin)
2.修改管理员密码
3.商品添加
4.商品列表
5.查询指定id商品
6.根据商品id删除商品
7.根据id修改商品价格
8.根据id修改指定商品库存
9.根据商品类别查询所有商品
10.查询指定价格区间的商品信息
根据项目要求,我们首先分析题目,知道此项目至少四个类:管理员类、商品类、系统类、测试类。
由于我们决定对此系统进行优化,要求能够对数据进行保存,所以我们用流的相关知识,将数据写入已经创建好的文档中,使其自动读写,以便管理,三个文档分别用于保存商品信息、id、user。
import java.util.Scanner;
import java.util.Vector;
/*
*只写了1,2,5功能,其他不想写了
*/
public class GoodsArrays {
private static VectorGoods vec = new VectorGoods();
public static void main(String[] args) {
GoodsArrays ga=new GoodsArrays();
ga.run();
}
public void run() {
info();
}
public void info() {
System.out.println("**********商品管理**********");
while (true) {
System.out.println("请选择你要操作的业务");
System.out.println("1.进货");
System.out.println("2.查询商品信息");
System.out.println("3.修改商品信息");
System.out.println("4.删除商品信息");
System.out.println("5.退出");
Scanner sc=new Scanner(System.in);
System.out.println("请输入操作:");
int op=sc.nextInt();
switch (op) {
case 1:
inGoods();
break;
case 2:
searchGoods();
break;
case 5:
System.out.println("退出系统");
System.exit(0);
break;
default:
break;
}
}
}
// 进货
public void inGoods() {
try {
Scanner sc = new Scanner(System.in);
System.out.println("请输入条码:");
int gid = sc.nextInt();
System.out.println("请输入商品类型:");
String cname = sc.next();
System.out.println("请输入商品名称:");
String gname = sc.next();
System.out.println("请输入报警数:");
int minNumber = sc.nextInt();
System.out.println("请输入市场价:");
double salePrice = sc.nextDouble();
System.out.println("请输入会员价:");
double vipPrice = sc.nextDouble();
System.out.println("请输入库存量:");
int amount = sc.nextInt();
vec.add(new Goods(gid, cname, gname, minNumber, salePrice, vipPrice, amount));
} catch (Exception e) {
e.printStackTrace();
}
}
// 查询
public void searchGoods() {
Scanner sc = new Scanner(System.in);
System.out.println("------查询商品------");
System.out.println("请选择查询类型");
System.out.println("a.查询所有商品:");
System.out.println("b.查询单个商品:");
String op = sc.next();
if (op.equalsIgnoreCase("a")) {
for (Goods goods : vec) {
System.out.println(goods);
}
} else if (op.equalsIgnoreCase("b")) {
System.out.println("请输入商品编号:");
int gid = sc.nextInt();
boolean findIndex = true;
for (Goods goods : vec) {
int id = goods.getGid();
if (id == gid) {
System.out.println(goods);
break;
} else {
findIndex = false;
}
}
if (findIndex == false) {
System.out.println("查询的商品不存在");
}
}
}
}
//实体类Goods
public class Goods {
private int gid;
private String cname;
private String gname;
private int minNumber;
private double salePrice;
private double vipPrice;
private int amount;
//重写Goods toString()方法,用于显示信息
@Override
public String toString() {
System.out.println("商品信息如下:");
return "[条码:" + gid + ",商品类型:" + cname + ",商品名称:" + gname + ",报警数:" + minNumber
+ ",市场价:" + salePrice + ",会员价:" + vipPrice + ",库存量:" + amount + "]";
}
//Goods构造函数,
public Goods(int gid, String cname, String gname, int minNumber, double salePrice, double vipPrice, int amount) {
super();
this.gid = gid;
this.cname = cname;
this.gname = gname;
this.minNumber = minNumber;
this.salePrice = salePrice;
this.vipPrice = vipPrice;
this.amount = amount;
}
public int getGid() {
return gid;
}
public void setGid(int gid) {
this.gid = gid;
}
public String getCname() {
return cname;
}
public void setCname(String cname) {
this.cname = cname;
}
public String getGname() {
return gname;
}
public void setGname(String gname) {
this.gname = gname;
}
public int getMinNumber() {
return minNumber;
}
public void setMinNumber(int minNumber) {
this.minNumber = minNumber;
}
public double getSalePrice() {
return salePrice;
}
public void setSalePrice(double salePrice) {
this.salePrice = salePrice;
}
public double getVipPrice() {
return vipPrice;
}
public void setVipPrice(double vipPrice) {
this.vipPrice = vipPrice;
}
public int getAmount() {
return amount;
}
public void setAmount(int amount) {
this.amount = amount;
}
}