下面是一个简单的登录示例：
代码复制展示：
public class ATMLogin {
public static void main(String[] args) {
// 设置用户名和密码
String username = "gqk"
String password = "520"
// 最多可以登录 3 次
for (int i = 0i <3i++) {
// 读取用户输入的用户名和密码
Scanner in = new Scanner(System.in)
System.out.print("请输入用户名：")
String inputUsername = in.nextLine()
System.out.print("请输入密码：")
String inputPassword = in.nextLine()
// 检查用户名和密码是否正确
if (inputUsername.equals(username) &&inputPassword.equals(password)) {
System.out.println("欢迎" + username + "登录！")
break// 登录成功，退出循环
} else {
System.out.println("用户名或密码错误，请重新输入！")
}
}
// 如果 3 次登录都失败，则提示用户
System.out.println("卡片已经被锁，请联系客服人员！")
}
}
回答不易望请采纳
import java.io.IOException
/**
* ATM机类
*
* 查看余额
*
* 取款
*
* 存款
*
* 退出系统
*
*
*
*/
public class ATM {
static double yue = 1200.00
public static void main(String[] arg) {
ATM localTest1 = new ATM()
localTest1.ATM_Operate()
}
/**
* ATM机的操作
*/
private void ATM_Operate() {
System.out.println("欢迎使用中国工商银行ATM取款机")
System.out.println("1、查看余额 2、取款")
System.out.println("3、存款0、退出")
System.out.print("请输入您需要的服务:")
byte[] buffer = new byte[512]
try {
int count = System.in.read(buffer)// 返回实际读取的字节数
System.out.print("您输入的是:")
for (int i = 0i <counti++) {
System.out.print("" + (char) buffer[i])
}
if ((char) buffer[0] == '1') {
// 查看余额
System.out.println("您的余额是：￥" + yue + "元")
System.out.println()
ATM_Operate()
} else if ((char) buffer[0] == '2') {
// 取款
withdrawal()
System.out.println()
ATM_Operate()
} else if ((char) buffer[0] == '3') {
// 存款
deposit()
System.out.println()
ATM_Operate()
} else if ((char) buffer[0] == '0') {
// 退出
System.out.println("您已经成功退出系统，谢谢你的使用")
System.exit(0)
} else {
System.out.println("输入不合法，请重新输入")
System.out.println()
ATM_Operate()
}
} catch (IOException e) {
e.printStackTrace()
}
}
/**
* 取款
*
* @throws IOException
*/
private void withdrawal() throws IOException {
byte[] buffer = new byte[512]
System.out.print("请输入您要取出的金额:￥")
int count2 = System.in.read(buffer)// 返回实际读取的字节数
System.out.print("您输入的金额是:")
for (int i = 0i <count2 - 1i++) {
System.out.print("" + (char) buffer[i])
}
System.out.println()
// 字符0 ~ 9对应ASCII值48 ~ 57
boolean flag = false
for (int i = 0i <count2 - 1i++) {
if ((char) buffer[i] >47 &&(char) buffer[i] <58) {
if (i == count2 - 2) {
flag = true
}
} else {
// 输入的字符不是数值
System.out.println("输入不合法，请重新输入")
withdrawal()
break
}
}
System.out.println()
if (flag) {
System.out.print("您已成功取出￥:")
String num = ""
for (int i = 0i <count2 - 1i++) {
System.out.print("" + (char) buffer[i])
num += (char) buffer[i]
}
yue -= Double.valueOf(num)
System.out.print("，现在余额￥:" + yue)
}
}
/**
* 存款
*
* @throws IOException
*/
private void deposit() throws IOException {
byte[] buffer = new byte[512]
System.out.print("请输入您要存入的金额:￥")
int count2 = System.in.read(buffer)// 返回实际读取的字节数
System.out.print("您输入的金额是:")
for (int i = 0i <count2 - 1i++) {
System.out.print("" + (char) buffer[i])
}
System.out.println()
// 字符0 ~ 9对应ASCII值48 ~ 57
boolean flag = false
for (int i = 0i <count2 - 1i++) {
if ((char) buffer[i] >47 &&(char) buffer[i] <58) {
if (i == count2 - 2) {
flag = true
}
} else {
// 输入的字符不是数值
System.out.println("输入不合法，请重新输入")
withdrawal()
break
}
}
System.out.println()
if (flag) {
System.out.print("您已成功存入￥:")
String num = ""
for (int i = 0i <count2 - 1i++) {
System.out.print("" + (char) buffer[i])
num += (char) buffer[i]
}
yue += Double.valueOf(num)
System.out.print("，现在余额￥:" + yue)
}
}
}
package arraylistimport java.util.Scanner
public class AtmDemo
{
public static void main(String[] args)
{
// TODO Auto-generated method stub
Scanner sc = new Scanner(System.in)
Boolean flag = true
int times = 0
while(flag){
times++
if(times == 4){
System.out.println("密码错误，请取卡")
break
}
System.out.println("请输入你的密码")
String password = sc.next()
if(password.equals("111111")){
Boolean moneyflag = true
while(moneyflag){
System.out.println("请输入金额")
int number = sc.nextInt()
if(number >= 0 &&number <= 1000 &&number % 100 == 0){
System.out.println("用户取了" + number + "元。交易完成")
moneyflag = false
}else{
System.out.println("请重新输入金额")
}
}
break
}else{
continue
}
}
}
}
