java项目实战-超市管理系统（六）实体源码与分析
package duan.entity;
/**
* goods 商品实体类
* @author duan
*/
public final class Goods
{
//数据库Goods表主鍵
private static int count=0;
private int gid;
private String gname;
private double gprice;
private int gnum;
/**
* 添加商品信息
* @param gname,gprice,gum
*/
public Goods(String gname,double gprice,int gum)
{
this.gname = gname;
this.gprice = gprice;
this.gnum = gum;
count++;
gid = count;
}
/**
* 展示所有商品
* @param gid,gname,gprice,gum
*/
public Goods(int gid,String gname,double gprice,int gum)
{
this.gid = gid;
this.gname = gname;
this.gprice = gprice;
this.gnum = gum;
}
/**
* 根据编号更改商品信息
* @param gid,gum
*/
public Goods(int gid,int gnum)
{
this.gid = gid;
this.gnum = gnum;
}
/**
* 根据编号更改商品信息
* @param gid,gprice
*/
public Goods(int gid,double gprice)
{
this.gid = gid;
this.gprice = gprice;
}
/**
* 根据编号更改商品信息
* @param gid,gname
*/
public Goods(int gid,String gname)
{
this.gid = gid;
this.gname = gname;
}
//共有-get、set-方法。
public int getGid()
{
return gid;
}
public void setGid(int gid)
{
this.gid = gid;
}
public String getGname()
{
return gname;
}
public void setGname(String gname)
{
this.gname = gname;
}
public double getGprice()
{
return gprice;
}
public void setGprice(double gprice)
{
this.gprice = gprice;
}
public int getGnum()
{
return gnum;
}
public void setGnum(int gnum)
{
this.gnum = gnum;
}
}
package duan.entity;
/**
* Gsales g购物结算实体类
* @author duan
*/
public final class Gsales
{ private static int count;
private int gsid;
private int gId;
private int sId;
private int sNum;
private String gName;
private double gPrice;
private int gNum;
/**
* 购物结算
* @param gId,sId,sNum
*/
public Gsales(int gId,int sId, int sNum)
{
this.gId = gId;
this.sId = sId;
this.sNum = sNum;
count++;
setGsid(count);
}
/**
* 展现商品列表
* @param gName,gPrice,gNum,allSnum
*/
public Gsales(String gName,double gPrice,int gNum)
{
this.gName = gName;
this.gPrice = gPrice;
this.gNum = gNum;
}
//共有set、get
public int getGId()
{
return gId;
}
public void setGId(int id)
{
gId = id;
}
public int getSId()
{
return sId;
}
public void setSId(int id)
{
sId = id;
}
public int getSNum()
{
return sNum;
}
public void setSNum(int num)
{
sNum = num;
}
public String getGName()
{
return gName;
}
public void setGName(String name)
{
gName = name;
}
public double getGPrice()
{
return gPrice;
}
public void setGPrice(double price)
{
gPrice = price;
}
public int getGNum()
{
return gNum;
}
public void setGNum(int num)
{
gNum = num;
}
public int getGsid() {
return gsid;
}
public void setGsid(int gsid) {
this.gsid = gsid;
}
}
package duan.entity;
/**
* SalesMan 售货员实体类
* @author duan
*/
public final class SalesMan
{ private static int count;
private int sId;
private String sName;
private String sPassWord;
/**
* 验证用户登陆
* @param sId,spassWord
*/
public SalesMan(int sId,String spassWord)
{
this.sId = sId;
this.sPassWord = spassWord;
}
/**
* 查询用户、更改用户密码
* @param sId,sName,sPassWord
*/
public SalesMan(int sId,String sName,String sPassWord)
{
this.sId = sId;
this.sName = sName;
this.sPassWord = sPassWord;
}
/**
* 添加用户
* @param NsNameame,sPassWord
*/
public SalesMan(String NsNameame, String sPassWord)
{
this.sName = NsNameame;
this.sPassWord = sPassWord;
count++;
sId = count;
}
//共有get.set方法
public int getSId()
{
return sId;
}
public void setSId(int id)
{
sId = id;
}
public String getSName()
{
return sName;
}
public void setSName(String name)
{
sName = name;
}
public String getSPassWord()
{
return sPassWord;
}
public void setSPassWord(String passWord)
{
sPassWord = passWord;
}
}
1.所有实体中，域中的字段都是private的，然后又get和set方法获取和设置字段，体现了封装的思想。
2.每个实体都有一个static的count字段。构造方法里面都有count++，用来自动生成ID号，然后再将这个值赋予各自的ID，这样就能每新建一个实体都自动生成一个ID，缺点就是，如果程序不是第一次启动，数据库里面可能已经有值了，而这个count还默认从0开始，这时候加入数据库就会出错，因为所有ID值在数据库里面都是对应的主键。完善的方法是count的初始值从数据库里面读取。
3.每个实体的构造方法都有不同的重载方法，这样调用时就会更加灵活和方便。
4.为了源码完整性，补充tool包，后面就不分析啦。
package duan.tools;
import java.util.Scanner;
import duan.page.GoodsPage;
import duan.page.MainPage;
import duan.page.SalesManPage;
/**
* 1.各種完成操作后的 选择下一步
* 2.界面选择操作
* @author duan
*/
public class ScannerChoice
{
/**
* @return double 键盘获取商品价格,小数点后两位
*/
public static double ScannerInfo()
{
double num = 0.00;
do
{
Scanner sc = new Scanner(System.in);
System.out.print("保留小数点后两位,请输入：");
String info = sc.next();
String regex = "(([1-9][0-9]*)\\.([0-9]{2}))|[0]\\.([0-9]{2})";//保留小数点后2位小数
if (info.matches(regex))
{
num = Double.parseDouble(info);
}else
{
System.err.println("！输入有误！");
continue;
}
break;
} while (true);
return num;
}
/**
* @return int 键盘获取商品数量
*/
public static int ScannerNum()
{
int num = 0;
String regex = "([1-9])|([1-9][0-9]+)";//商品数量
do
{
Scanner sc = new Scanner(System.in);
System.out.print("请输入：");
String nums = sc.next();
if (nums.matches(regex))
{
num = Integer.parseInt(nums);
}else
{
System.err.println("！输入有误！");
continue;
}
break;
} while (true);
return num;
}
/**
* @return String 获取的键盘输入
*/
public static String ScannerInfoString()
{
Scanner scanner = new Scanner(System.in);
System.out.print("请输入：");
return scanner.next();
}
/**
* 获取用户-更改完商品-下一步
* 获取用户-删除完商品-下一步
* 获取用户-添加完商品-下一步
* @param 调用者
*/
public static void changedInfoNext(String oper)
{
do
{
System.out.println("是否继续进行-当前操作:(Y/N)");
String choice = ScannerChoice.ScannerInfoString();
//在JAVA中: Equals比较的是值,==比较的是地址
if ("y".equals(choice) || "Y".equals(choice))
{
//下面的嵌套if-else 是让用户选择继续操作当前步骤所跳转到指定页面。（因为不同函数调用，跳转的指定函数不同）
if ("upateGoodsPage".equals(oper))
{
GoodsPage.updateGoodsPage();
}else if ("deleteGoodsPage".equals(oper))
{
GoodsPage.deleteGoodsPage();
}else if ("addGoodsPage".equals(oper))
{
GoodsPage.addGoodsPage();
}
//上面的嵌套结束
}else if ("N".equals(choice) || "n".equals(choice))
{
MainPage.MaintenancePage();
}
System.out.println("\n输入有误！请重新输入.");
} while (true);
}
/**
* 获取用户-更改-完售货员-下一步
* 获取用户-添加-完售货员-下一步
* 获取用户-查询-完售货员-下一步
* 获取用户-删除-完售货员-下一步
* @param 调用者
*/
public static void choiceSalesManNext(String oper)
{
do
{
System.out.println("是否继续进行-当前操作:(Y/N)");
String choice = ScannerChoice.ScannerInfoString();
if ( "y".equals(choice) || "Y".equals(choice) )
{
//下面的嵌套if-else 是让用户选择继续操作当前步骤所跳转到指定页面。（因为不同函数调用，跳转的指定函数不同）
if ("updateSalesMan".equals(oper))
{
SalesManPage.updateSalesManPage();
}else if ("deleteSalesMan".equals(oper))
{
SalesManPage.deleteSalesManPage();
}else if ("addSalesMan".equals(oper))
{
SalesManPage.addSalesManPage();
}else if ("querySalesMan".equals(oper))
{
SalesManPage.querySalesManPage();
}
//上面的嵌套结束
}else if ("N".equals(choice) || "n".equals(choice))
{
MainPage.salesManManagementPage();
}
System.err.println("\t输入有误！");
} while (true);
}
}
package duan.tools;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import duan.dao.GoodsDao;
import duan.db.DbClose;
import duan.db.DbConn;
import duan.entity.Goods;
import duan.entity.SalesMan;
/**
* 查询&&打印 函数工具(后期优化可能会删)
*@author duan
*/
public final class QueryPrint
{
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
/**
* 模糊查询并陈列查询信息函数小工具
* @param oper 调用者
* @return 查询到的信息的gid,如果返回值等于-1，则代表查询异常。
*/
public static int query(String oper)
{
int gid = -1;
String shopping = ScannerChoice.ScannerInfoString(); //键盘获取商品名字
ArrayList goodsList = new QueryPrint().queryGoodsKey(-1,shopping); //根据键盘获取的商品名字調用 精确查询函数，確定用戶所要操作的数据
if (goodsList == null || goodsList.size() <= 0)
{
System.err.println("\t！！查无此商品 ！！");
//調用选择下一步函数
ScannerChoice.changedInfoNext(oper);
}else //查到有此商品，实现进行 更改商品 信息操作！
{
Goods goods = goodsList.get(0);
System.out.println("\t\t\t\t\t商品列表\n\n");
System.out.println("\t商品编号\t\t商品名称\t\t商品价格\t\t商品数量\t\t备注\n");
System.out.print("\t"+goods.getGid()+"\t\t"+goods.getGname()+"\t\t"+goods.getGprice()+"\t\t"+goods.getGnum());
if (goods.getGnum()==0)
{
System.out.println("\t\t该商品已售空");
}else if (goods.getGnum()<10)
{
System.out.println("\t\t该商品已不足10件");
}else
{
System.out.println("\t\t-");
}
gid = goods.getGid(); //将商品编号返回给调用者
}
return gid;
}
/**
* 模糊查询函数小工具
* @return int 当商品件数有且只有一件时返回商品gid号，商品已售空时返回 -1. >1件时返回-2 . 查无此商品时返回-3
*
*/
public static int querySettlement()
{
int gid = -1;
ArrayList goodsSettlement = new GoodsDao().queryGoods(3);//調用 关键字查询函数
if (goodsSettlement == null || goodsSettlement.size() <= 0)
{
System.err.println("\t！！查无此商品 ！！\n");
gid = -3;
}else //查到有此商品，实现进行 更改商品 信息操作！
{
System.out.println("\t\t\t\t\t商品列表\n\n");
System.out.println("\t商品编号\t\t商品名称\t\t商品价格\t\t商品数量\t\t备注\n");
for (int i = 0; i < goodsSettlement.size(); i++)
{
Goods goods = goodsSettlement.get(i);
if (goods.getGnum() > 0)
{
System.out.print("\t"+goods.getGid()+"\t\t"+goods.getGname()+"\t\t"+goods.getGprice()+"\t\t"+goods.getGnum());
if (goods.getGnum()==0)
{
System.out.println("\t\t该商品已售空");
}else if (goods.getGnum()<10)
{
System.out.println("\t\t该商品已不足10件");
}else
{
System.out.println("\t\t-");
}
if (goodsSettlement.size()==1)
{
gid = goods.getGid(); //将商品编号返回给调用者
}else
{
gid = -2;
}
}
}
}
return gid;
}
/**
* 根据商品 gid or gName查询商品
* @param 商品id,商品名称
* @return 商品信息
*/
public ArrayList queryGoodsKey(int gId,String gName)
{
ArrayList goodsList = new ArrayList();
conn = DbConn.getconn();
String sql = "SELECT * FROM GOODS WHERE GID=? OR GNAME=?";
try
{
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, gId);
pstmt.setString(2, gName);
rs = pstmt.executeQuery();
while (rs.next())
{
int gid = rs.getInt("gid");
String gname = rs.getString(2);
double gprice = rs.getDouble(3);
int gnum = rs.getInt(4);
Goods goods = new Goods(gid,gname,gprice,gnum);
goodsList.add(goods);
}
} catch (SQLException e)
{
e.printStackTrace();
}finally
{
DbClose.queryClose(pstmt, rs, conn);
}
return goodsList;
}
/**
* 精确查询售货员信息
* @param 售货员名字
* @return
*/
public ArrayList querySalesMan(String sName)
{
ArrayList SalesManList = new ArrayList();
conn = DbConn.getconn();
String sql = "SELECT * FROM SALESMAN WHERE SNAME=?";
try
{
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, sName);
rs = pstmt.executeQuery();
while (rs.next())
{
int sid = rs.getInt("sid");
String sname = rs.getString(2);
String sPassWord = rs.getString(3);
SalesMan salesMan = new SalesMan(sid,sname,sPassWord);
SalesManList.add(salesMan);
}
} catch (SQLException e)
{
e.printStackTrace();
}finally
{
DbClose.queryClose(pstmt, rs, conn);
}
return SalesManList;
}
}
package duan.tools;
import java.math.BigDecimal;
/**
* 由于Java的简单类型不能够精确的对浮点数进行运算，这个工具类提供精
* 确的浮点数运算，包括加减乘除和四舍五入.
*
* 注意：此代码将加减乘除四舍五入方法已实现，但本项目中并未全部使用.
* @author lyons(zhanglei)
*/
public class Arith
{
private static final int DEF_DIV_SCALE = 2; //默认除法运算精度
private Arith(){}
/**
* 提供精确的加法运算。
* @param v1 被加数
* @param v2 加数
* @return 两个参数的和
*/
public static double add(double v1,double v2)
{
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.add(b2).doubleValue();
}
/**
* 提供精确的减法运算。
* @param v1 被减数
* @param v2 减数
* @return 两个参数的差
*/
public static double sub(double v1,double v2)
{
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.subtract(b2).doubleValue();
}
/**
* 提供精确的乘法运算。
* @param v1 被乘数
* @param v2 乘数
* @return 两个参数的积
*/
public static double mul(double v1,double v2)
{
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.multiply(b2).doubleValue();
}
/**
* 提供（相对）精确的除法运算，当发生除不尽的情况时，精确到
* 小数点以后2位，以后的数字四舍五入。
* @param v1 被除数
* @param v2 除数
* @return 两个参数的商
*/
public static double div(double v1,double v2)
{
return div(v1,v2,DEF_DIV_SCALE);
}
/**
* 提供（相对）精确的除法运算。当发生除不尽的情况时，由scale参数指
* 定精度，以后的数字四舍五入。
* @param v1 被除数
* @param v2 除数
* @param scale 表示表示需要精确到小数点以后几位。
* @return 两个参数的商
*/
public static double div(double v1,double v2,int scale)
{
if(scale<0)
{
throw new IllegalArgumentException(
"The scale must be a positive integer or zero");
}
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.divide(b2,scale,BigDecimal.ROUND_HALF_UP).doubleValue(); //BigDecimal.ROUND_HALF_UP 向“最接近的”数字舍入，如果与两个相邻数字的距离相等，则为向上舍入的舍入模式。
}
/**
* 提供精确的小数位四舍五入处理。
* @param v 需要四舍五入的数字
* @param scale 小数点后保留几位
* @return 四舍五入后的结果
*/
public static double round(double v,int scale)
{
if(scale<0)
{
throw new IllegalArgumentException("The scale must be a positive integer or zero");
}
BigDecimal b = new BigDecimal(Double.toString(v));
BigDecimal one = new BigDecimal("1");
return b.divide(one,scale,BigDecimal.ROUND_HALF_UP).doubleValue();
}
}