用java语言编写一个小型的银行系统代码

private int balance = 0

private  String username = "A"

private  String password = "B"

public void bank() {

    Scanner scan = new Scanner(System.in)

    String  temp

    while (true) {

        System.out.println("输入账号：")

        if (scan.hasNext()) {

            temp = scan.next()

            if (temp.equals(username)) {

                break

            } else {

                System.out.println("输入错误")

            }

        }

    }

    while (true) {

        System.out.println("输入密码：")

        if (scan.hasNext()) {

            temp = scan.next()

            if (temp.equals(password)) {

                break

            } else {

                System.out.println("输入错误")

            }

        }

    }

    System.out.println("登录成功")

    while (true) {

        System.out.println("输入 *** 作：")

        if (scan.hasNext()) {

            temp = scan.next()

            switch (temp) {

                case "存款":

                    int x = 0

                    while (true) {

                        System.out.println("输袜伍入存款金额：")

            镇备            if (scan.hasNextInt()) {

                            x = scan.nextInt()

                            break

                        } else {

                            System.out.println("输入错误")

                            scan.next()

                        }

                    }

                    balance += x

                    break

                case "取款":

                    int y = 0

                    while (true) {

                        System.out.println("输入取款金额：")

                告旅或        if (scan.hasNextInt()) {

                            y = scan.nextInt()

                            if (balance < y) {

                                System.out.println("余额不足")

                                continue

                            }

                            break

                        } else {

                            System.out.println("输入错误")

                            scan.next()

                        }

                    }

                    balance -= y

                    break

                case "余额":

                    System.out.println("余额：" + balance)

                    break

                case "终止":

                    System.exit(0)

                default:

                    System.out.println("未知 *** 作")

            }

        }

    }

package pack.money.persistentimport java.sql.Connection

import java.sql.PreparedStatement

import java.sql.ResultSet

import java.util.ArrayListimport pack.money.entity.Client

import pack.money.entity.ClientMessage

public class ClientPersistent {

//private static int a=0

private static String t,b//t是password b是clinetname

private static ClientPersistent sp

public static ClientPersistent getClientPersistent() {

if (sp == null) {

sp = new ClientPersistent()

}

return sp

}

private ClientMessage getClientMessage(ResultSet rs) throws Exception{

ClientMessage student=new ClientMessage()

student.setMoney(rs.getFloat("money"))

student.setType(rs.getString("type"))

student.setClientName(rs.getString("ClientName"))

student.setTransactionID(rs.getInt("TransactionID"))

return student

}

public Client login(Connection con,String ClientName,String password) throws Exception{

String sql="select balance,password,ClientName from Client where ClientName=? and password=?"

PreparedStatement ps=con.prepareStatement(sql)

ps.setString(1, ClientName)

ps.setString(2, password)

ResultSet rs=ps.executeQuery()

t=password

b=ClientName

System.out.println(t)

System.out.println(b)

if(rs.next()){

Client client=new Client()

client.setClientName(rs.getString("ClientName"))

client.setPassword(rs.getString("password"))

return client }

throw new Exception("Can not login, the accountID or password has error. ")

} public void save(Connection con ,String money)throws Exception

{ // a++

String s="save"

float g=Float.parseFloat(money)

String sql="update Client set balance=balance+? where ClientName=?"

String sql1="insert into ATMTransaction(ClientName,Type,money) values(?,?,?) "

PreparedStatement ps=con.prepareStatement(sql)

PreparedStatement ps1=con.prepareStatement(sql1)

ps.setFloat(1, g)

ps.setString(2,b)

//ps1.setInt(1,a)

ps1.setString(1,b)

ps1.setString(2,s)

ps1.setFloat(3,g)

ps.executeUpdate()

ps1.executeUpdate()

}

public void withDraw (Connection con ,String money)throws Exception

{ //a++

String s="WithDraw"

float x=Float.parseFloat(money)

String sql="update Client set balance=balance-? where ClientName=?"

String sql1="insert into ATMTransaction(ClientName,Type,money) values(?,?,?)"

PreparedStatement ps=con.prepareStatement(sql)

PreparedStatement ps1=con.prepareStatement(sql1)

ps.setFloat(1, x)

ps.setString(2,b)

//ps1.setInt(1,a)

ps1.setString(1,b)

ps1.setString(2,s)

ps1.setFloat(3,x)

ps.executeUpdate()

ps1.executeUpdate()

}

public String changePassword(Connection con, String OldPassWord,String newPassWord1,String newPassWord2)

throws Exception

{

if(t.equals(OldPassWord))

{

if(newPassWord1.equals(newPassWord2))

{

String sql="update Client set password=? where ClientName=?"

PreparedStatement ps=con.prepareStatement(sql)

ps.setString(1, newPassWord1)

ps.setString(2,b)

ps.executeUpdate()

String j="dsfasdf"

return j

}

else

{System.out.print("确认密码错误！")<br> return null}

}

else

{ return null

}

}

public ArrayList<ClientMessage>disPlayAll(Connection con ) throws Exception

{

String sql="select * from ATMTransaction where ClientName=? "

PreparedStatement ps=con.prepareStatement(sql)

ps.setString(1,b)

System.out.println(b+"****b****")

ResultSet rs=ps.executeQuery()

ArrayList<ClientMessage>message=new ArrayList<ClientMessage>()

while(rs.next()){

message.add(this.getClientMessage(rs))

}

return message

}

public float showBalance(Connection con ) throws Exception

{

String sql="select balance from Client where ClientName=?"

PreparedStatement ps=con.prepareStatement(sql)

ps.setString(1, b)

ResultSet rs=ps.executeQuery()

if(rs.next())

{

float s

s=rs.getFloat("balance")

return s

}

else return 0

}

}

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