java模拟ATM功能的详细解析

package ATM;
 
import java.util.Scanner;
 
public class ATMSystem 
{
 CustomerDAO dao=new CustomerDAO();
 Scanner input=new Scanner(System.in);
 private int id;
 public ATMSystem()
 {
 
 }
 public void Regist()
 {
 System.out.println("注册卡号：");
 int myid=input.nextInt();
 System.out.println("注册用户名：");
 String myname=input.next();
 System.out.println("注册密码：");
 String mypwd=input.next();
 System.out.println("输入存入金额：");
 int mymoney=input.nextInt();
 dao.Regist(myid, mypwd, myname, mymoney);
 }
 public boolean login()
 {
 System.out.println("请输入密码：");
 String mypwd=input.next();
 id=dao.login(mypwd);
 if(id==-1)
 {
  System.out.println("登录失败！");
  return false;
 }
 else
 {
  System.out.println("登陆成功！");
  return true;
 }
 }
 public void query(int id)
 {
 Customer cust=dao.query(id);
 System.out.println("********************");
 System.out.println("卡号："+cust.getid());
 System.out.println("余额："+cust.getmoney());
 System.out.println("用户名："+cust.getname());
 System.out.println("********************");
 }
 public void save()
 {
 System.out.println("输入存款金额：");
 int money=input.nextInt();
 dao.update_save(id, money);
 }
 public void get()
 {
 System.out.println("********************");
 System.out.println("输入取款金额：");
 int money=input.nextInt();
 dao.update_get(id, money);
 System.out.println("********************");
 }
 public void change()
 {
 System.out.println("请输入转账卡号：");
 int inid=input.nextInt();
 System.out.println("请输入转账金额：");
 int money=input.nextInt();
 dao.change(id, inid, money);
 }
 public void begin()
 {
 int num=-1;
 int Num=0;
 System.out.println("请选择功能：");
 System.out.println("1.注册      2.登录");
 Num=input.nextInt();
 switch(Num)
 {
 case 1:
  Regist();
  break;
 case 2:
  if(login())
  {
  while(num!=0)
  {
   System.out.println("********************");
   System.out.println("欢迎欢迎，热烈欢迎");
   System.out.println("请选择功能：");
   System.out.println("1.存款     2.取款   3.查询   4.转账  0.退出");
   System.out.println("********************");
   num=input.nextInt();
   switch(num)
   {
   case 1:
   save();
   break;
   case 2:
   get();
   break;
   case 3:
   query(id);
   break;
   case 4:
   change();
   break;
   case 0:
   System.out.println("谢谢使用！");
   break;
   }
  }
  }
  else
  {
  System.out.println("登录失败，账号、密码错误！");
  }
 break;
 default:
  break;
 }
 }
}

package ATM;
 
public class Customer 
{
 private int id;
 private String pwd;
 private int money;
 private String name;
 public int getid()
 {
 return id;
 }
 public void setid(int newid)
 {
 id=newid;
 }
 public String getpwd()
 {
 return pwd;
 }
 public void setpwd(String newpwd)
 {
 pwd=newpwd;
 }
 public String getname()
 {
 return name;
 }
 public void setname(String newname)
 {
 name=newname;
 }
 public int getmoney()
 {
 return money;
 }
 public void setmoney(int newmoney)
 {
 money=newmoney;
 }
}

package ATM;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
 
 
public class CustomerDAO
{
 private Connection conn=null;
 private java.sql.PreparedStatement p=null;
 public CustomerDAO()
 {
 try {
  Class.forName("org.gjt.mm.MySQL.Driver");
 } catch (ClassNotFoundException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 try {
  conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql", "root", "");
 } catch (SQLException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 }
 public int login(String mypwd)
 {
 String sql="select * from mysql where pwd = ?";
 try 
 {
  p=conn.prepareStatement(sql);
  p.setString(1, mypwd);
  ResultSet rs=p.executeQuery();
  if(rs.next())
  {
  return rs.getInt("id");
  }
  rs.close();
  p.close();
  conn.close();
 } 
 catch (SQLException e) 
 {
  e.printStackTrace();
 }
 return -1;
 }
 public Customer query(int id)
 {
 Customer cust=new Customer();
 try
 {
  String sql="select * from mysql where id = ?";
  p=conn.prepareStatement(sql);
  p.setInt(1, id);
  ResultSet rs=p.executeQuery();
  if(rs.next())
  {
  cust.setid(rs.getInt("id"));
  cust.setmoney(rs.getInt("money"));
  cust.setname(rs.getString("name"));
  cust.setpwd(rs.getString("pwd"));
  }
 }
 catch (Exception e) {
  // TODO: handle exception
 }
 return cust;
 
 }
 public void update_get(int id,int money) 
 {
 String sql="select * from mysql where id = ?";
 try 
 {
  p=conn.prepareStatement(sql);
  p.setInt(1, id);
  ResultSet rs=p.executeQuery();
  if(rs.next())
  {
  if(rs.getInt("money")

package ATM;
 
public class Test 
{
 public static void main(String[] args) 
 {
 // TODO Auto-generated method stub
 ATMSystem ATM=new ATMSystem();
 while(true)
 {
  ATM.begin();
 }
 }
 
}