案例：
模拟实现ATM机的功能：
功能描述：
- 实现用户程登录及创建，实现查询余额，取出，存款，转账等
1、 测试 类：
public class Atm {
public static void main(String[] args) {
Method me =new Method();
me.start();
}
2、用户类：
public class Usr {
private String account ;//账户
private String cood;//密码
private long balance ;//余额
public Usr(String account,String cood,long balance) {
this.cood=cood;
this.account=account;
this.balance=balance;
}
public Usr() {
}
public void setCood(String cood) {
this.cood=cood;
}
public String getCood() {
return cood;
}
public void setAccount(String account) {
this.account=account;
}
public String getAccount() {
return account;
}
public void setBalance(long balance) {
this.balance=balance;
}
public long getBalance() {
return balance;
}
@Override
public boolean equals(Object obj) {
return super.equals(obj);
}
@Override
public String toString() {
return "Usr{" +
"account='" + account + ''' +
", cood='" + cood + ''' +
", balance=" + balance +
'}';
}
}
3、方法类:
import java.util.ArrayList;
import java.util.Random;
import java.util.Scanner;
public class Method {
Random ran = new Random();
ArrayList<Usr> list = new ArrayList<Usr>();
Scanner sc = new Scanner(System.in);
Usr usr = new Usr();
public void method() { //创建4个初始账户
Usr usr = new Usr("123456", "666666", 100000);
Usr usr = new Usr("888888", "666666", 200000);
Usr usr = new Usr("666666", "666666", 300000);
Usr usr = new Usr("999999", "666666", 400000);
list.add(usr);
list.add(usr);
list.add(usr);
list.add(usr);
}
public void start() {
method();
System.out.println("这里创建了个供测试的账户分别是：");
System.out.println(list.get());
System.out.println(list.get());
System.out.println(list.get());
System.out.println(list.get());
System.out.println("欢迎使用本公司ATM机，请选择您需要的服务");
method();
}
public void method() { // 选择服务编号
System.out.println(".登陆 2.创建账户 3.退出");
int a = shuRu(, 3);
switch (a) {
case:
// 有账户，直接登陆；
dl();
break ;
case:
// 无账户，创建账户
cj();
break;
case:
break;
}
}
public int shuRu(int min, int max) { //输入
int aa =;
while (true) {
String str = sc.nextLine();
try {
int a = Integer .valueOf(str);
if (a >= min && a <= max) {
aa = a;
break;
} else {
System.out.println("请输入正确的服务编号");
}
} catch (Exception e) {
System.out.println("输入不合法,请您输入正确的服务编号");
}
}
return aa;
}
public int shuRu(int min) { //输入
int aa =;
while (true) {
String str = sc.nextLine();
try {
int a = Integer.valueOf(str);
if (a >= min && a <= Integer.MAX_VALUE) {
aa = a;
break;
} else {
System.out.println("请输入合理的金额，您最小的操作金额为元");
}
} catch (Exception e) {
System.out.println("输入不合法");
}
}
return aa;
}
public void cj() { // 创建账户
System.out.println("请输入您的六位密码，您共有三次输入机会");
String str = method020101();
if (str == "") {
System.out.println("您的输入机会以用完，请重新选择服务");
method();
} else {
System.out.println("请确认您的六位密码，您共有三次确认机会");
String str = method020101();
if (str == "") {
System.out.println("您的输入机会以用完，请重新选择服务");
method();
} else {
boolean a = method(str1, str2); //比较两次输入
if (a) {
String str = sczh();
usr.setA cc ount(str3);
usr.setCood(str);
list.add(usr);
System.out.println("恭喜您，您的账户创建成功，账号为：" + str + "您的密码为：" + str1);
fw(str, str1);
} else {
System.out.println("您两次输入的密码不同，请选择您需要的服务");
method();
}
}
}
}
public String method() { // 输入密码
String str = "";
for (int a =; a >= 1; a--) {
String str = sc.nextLine();
try {
int aa = Integer.valueOf(str);
if (str.length() == 6) {
str = str;
a =;
} else {
if (a >) {
System.out.println("请您输入位密码,您还有" + (a - 1) + "次机会");
} else {
break;
}
}
} catch (Exception e) {
if (a >) {
System.out.println("输入格式不合法，请输入位数字，例如666666");
}
}
}
return str;
}
public boolean method(String str1, String str2) { //比较两次输入
boolean a;
if (str.equals(str2)) {
a = true;
} else {
a = false;
}
return a;
}
public String sczh() { //随机生成账户
String str = "";
for (int b =; b < 6; b++) {
int a = ran.nextInt();
str += a;
}
for (int a =; a < list.size(); a++) {
if (str.equals(list.get(a).getAccount())) {
System.out.println("该账户以存在，请重新选择服务编号");
method();
break;
}
}
return str;
}
public void dl() { //登录
System.out.println("尊敬的客户，您好，请输入您的账户,您共有三次输入机会");
String zz;
String str;
for (int a =; a >= 1; a--) {
str = sc.nextLine();
try {
int aa = Integer.valueOf(str);
if (str.length() ==) {
for (int cc =; cc < list.size(); cc++) {
if (str.equals(list.get(cc).getAccount())) {
System.out.println("请输入您的六位密码");
String str = method020101();
if (str.equals(list.get(cc).getCood())) {
zz = list.get(cc).getAccount();
System.out.println("登录成功，请选择您需要的服务");
fw(zz, str);
a =;
break;
} else {
System.out.println("密码输入错误，请重新选择服务编号");
method();
a =;
cc = list.size();
break;
}
} else if (!str.equals(list.get(cc).getAccount()) && cc == list.size() -) {
System.out.println("账户不存在，请重新输入");
}
}
} else {
if (a >) {
System.out.println("输入错误，请重新输入您的账户,您还有" + (a -) + "次机会");
} else {
System.out.println("您的输入机会以用完，请重新选择服务");
method();
a =;
break;
}
}
} catch (Exception e) {
if (a >) {
System.out.println("输入格式错误，请重新输入您的账户,您还有" + (a -) + "次机会");
} else {
System.out.println("您的输入机会以用完，请重新选择服务");
method();
a =;
break;
}
}
}
}
public void fw(String account, String cood) {
System.out.println("尊敬的客户，您好，请选择您需要的服务：.修改密码 2.存款 3.取款 4.查询余额 5.转账 0.退出");
int a = shuRu(, 5);
int b = czzh(account, cood, a);
switch (a) {
case:
fw(account, cood, b);
break;
case:
fw(account, cood, b);
break;
case:
fw(account, cood, b);
break;
case:
fw(account, cood, b);
break;
case:
fw(account, cood, b);
break;
case:
System.out.println("服务结束，欢迎您的下次使用");
}
}
public void fw(String account, String cood, int b) {
System.out.println("您确定要修改您的密码，、确定 2、返回");
int bb = shuRu(, 2);
switch (bb) {
case:
System.out.println("请输入您的原密码");
String str = method();
boolean aa = method(str, cood);
if (aa) {
System.out.println("请输入您的新密码");
String str = method020101();
System.out.println("请确认您的新密码");
String str = method020101();
boolean a = method(str1, str2);
if (a) {
list.get(b).setCood(str);
System.out.println("您的密码修改成功，您的新密码为：" + str);
fw(account, cood);
} else {
System.out.println("您两次输入的密码不同，请重新选择服务");
fw(account, cood);
}
} else {
System.out.println("您的密码输入错误，请重新选择服务");
fw(account, cood);
}
break;
case:
fw(account, cood);
break;
}
}
public void fw(String account, String cood, int b) {//不可能这个账户不存在，所以没有进行判断
System.out.println("请输入您要存入的金额");
int a = shuRu();
list.get(b).setBalance((list.get(b).getBalance()) + a);
System.out.println("存款成功，您的余额为：" + list.get(b).getBalance());
fw(account, cood);
}
public void fw(String account, String cood, int b) {
System.out.println("请输入你要取出的金额");
int a = shuRu();
if (a <= list.get(b).getBalance()) {
list.get(b).setBalance((list.get(b).getBalance()) - a);
System.out.println("取款成功，您的余额为：" + list.get(b).getBalance());
fw(account, cood);
} else {
System.out.println("您的余额不足，请确认余额");
fw(account, cood);
}
}
public void fw(String account, String cood, int b) {
System.out.println("您的余额为：" + list.get(b).getBalance());
fw(account, cood);
}
public void fw(String account, String cood, int b) {
System.out.println("请输入对方的账户");
String str = fw();
boolean a = fw(str);
if (a) {
System.out.println("请输入您要转账的金额");
int c = shuRu();
if (c <= list.get(b).getBalance()) {
list.get(b).setBalance(list.get(b).getBalance() - c);
System.out.println("转账成功，您的余额为：" + list.get(b).getBalance());
fw(account, cood);
} else {
System.out.println("您的余额不足，请确认您的余额后重试");
fw(account, cood);
}
} else {
System.out.println("账户不存在，请确认后再操作");
fw(account, cood);
}
}
public String fw() {
String str;
while (true) {
String str = sc.nextLine();
try {
int aa = Integer.valueOf(str);
if (str.length() == 6) {
str = str;
break;
} else {
System.out.println("请输入正确的六位账户");
}
} catch (Exception e) {
System.out.println("格式错误，请输入正整数");
}
}
return str;
}
public boolean fw(String str) {
boolean aa = false;
for (int a =; a < list.size(); a++) {
if (str.equals(list.get(a).getAccount())) {
aa = true;
}
}
return aa;
}
public int czzh(String account, String cood, int a) { //查找账户在集合中是第几号元素
int aa = -;
for (int b =; b < list.size(); b++) {
if (account.equals(list.get(b).getAccount())) {
aa = b;
}
}
return aa;
}
}
如有不同看法，欢迎留下您宝贵的意见！