要求：
要实现开户、取款、存款、转账的功能；
分析：
①用户对象-User：身份证号，姓名，性别，年龄；
②账户对象-Account：账号，密码，余额；
方法：
①根据身份证找到用户对象
②自动生成账号
规则自己定义：比如随机数
③开户方法
要求：
首先根据身份证，看看用户是否存在；
如果不存在，注册用户（添加到用户数组），然后生成账户信息，执行开户；
如果存在，直接生成账户信息，执行开户；
开户：创建账户对象，放到用户的账户数组中；
开户成功后，输出所有用户和用户的账户信息；
④登录
根据账号和密码登录；
登录成功后，可以执行取款、存款、转账操作
⑤取款方法
⑥存款方法
⑦转账方法
在Myeclipse中完成，新建4个类
User
package ebank;
public class User {
private String cardId;
private String name;
private String gender;
private int age;
private Account[] acts = new Account[5];
private int count = 0;
public User() {
super();
}
public User(String cardId, String name, String gender, int age) {
super();
this.cardId = cardId;
this.name = name;
this.gender = gender;
this.age = age;
}
public String getCardId() {
return cardId;
}
public void setCardId(String cardId) {
this.cardId = cardId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Account[] getActs() {
return acts;
}
public void setActs(Account[] acts) {
this.acts = acts;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
public void addAct(Account act){
if(count<acts.length){
acts[count] = act;
count++;
}else{
System.out.println("账户已满！");
}
}
}
Account
package ebank;
public class Account {
private String actNo;
private String passwd;
private double balance;
public Account() {
super();
}
public Account(String actNo, String passwd, double balance) {
super();
this.actNo = actNo;
this.passwd = passwd;
this.balance = balance;
}
public String getActNo() {
return actNo;
}
public void setActNo(String actNo) {
this.actNo = actNo;
}
public String getPasswd() {
return passwd;
}
public void setPasswd(String passwd) {
this.passwd = passwd;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
}
AccountService
package ebank;
import java.util.Scanner;
import java.util.UUID;
public class AccountService {
private User[] users;
private int size;
private int count = 0;
public AccountService() {
size = 10;
users = new User[size];
}
public AccountService(int size) {
this.size = size;
users = new User[size];
}
public User getUserById(String cardId){
User user = null;
for(int i=0;i<users.length;i++){
User u = users[i];
if(u!=null){
if(u.getCardId().equals(cardId)){
user = u;
}
}else{
break;
}
}
return user;
}
public void printInfo(){
System.out.println("身份证\t姓名\t性别\t年龄");
for(int i=0;i<users.length;i++){
User u = users[i];
if(u!=null){
System.out.println(u.getCardId()+"\t"+u.getName()+"\t"+u.getGender()+"\t"+u.getAge());
Account[] acts = u.getActs();
if(acts!=null){
for(int j=0;j<acts.length;j++){
Account a = acts[j];
if(a!=null){
System.out.println("\t\t账户："+a.getActNo()+","+a.getPasswd()+","+a.getBalance());
}else{
break;
}
}
}
}else{
break;
}
}
}
public String generateActNo(){
String uuidStr = UUID.randomUUID().toString();
String actNo = uuidStr.substring(0, 8);
return actNo;
}
public void registUser(User user){
if(count<users.length){
users[count] = user;
count++;
System.out.println("开户成功！");
}else{
System.out.println("开户数量已满！");
}
}
public Account getActByNo(String actNo){
Account act = null;
for(int i=0;i<users.length;i++){
User u = users[i];
if(u!=null){
Account[] acts = u.getActs();
if(acts!=null){
for(int j=0;j<acts.length;j++){
Account a = acts[j];
if(a!=null){
if(a.getActNo().equals(actNo)){
act = a;
break;
}
}else{
break;
}
}
}
}else{
break;
}
}
return act;
}
public Account login(String actNo,String passwd){
Account act = null;
for(int i=0;i<users.length;i++){
User u = users[i];
if(u!=null){
Account[] acts = u.getActs();
if(acts!=null){
for(int j=0;j<acts.length;j++){
Account a = acts[j];
if(a!=null){
if(a.getActNo().equals(actNo)&&a.getPasswd().equals(passwd)){
act = a;
break;
}
}else{
break;
}
}
}
}else{
break;
}
}
return act;
}
public void getMoney(Account act,double money){
double balance = act.getBalance();
if(balance>=money){
act.setBalance(act.getBalance()-money);
System.out.println(act.getActNo()+"成功取出"+money+"元!");
}else{
System.out.println("账户余额不足！");
}
}
public void saveMoney(Account act,double money){
act.setBalance(act.getBalance()+money);
System.out.println(act.getActNo()+"成功存入"+money+"元!");
}
public void transfer(Account outAct,Account inAct,double money){
double balance = outAct.getBalance();
if(balance>=money){
outAct.setBalance(outAct.getBalance()-money);
inAct.setBalance(inAct.getBalance()+money);
System.out.println(outAct.getActNo()+"成功转出"+money+"元到"+inAct.getActNo()+"!");
}else{
System.out.println("账户余额不足！");
}
}
public void run(){
System.out.println("欢迎来到风云银行！");
Scanner sc = new Scanner(System.in);
Account loginAct = null;
while(true){
System.out.println("请输入你的操作：(1.开户,2.登录,3.退出)");
String comd = sc.next();
if(comd.equals("1")||comd.equals("开户")){
System.out.println("请输入身份证号码：");
String cardId = sc.next();
User user = getUserById(cardId);
if(user!=null){
String actNo = generateActNo();
Account act = new Account(actNo, "000000", 0.0);
user.addAct(act);
printInfo();
}else{
System.out.println("请依次输入用户信息(姓名，性别，年龄)");
String name = sc.next();
String gender = sc.next();
int age = sc.nextInt();
user = new User(cardId, name, gender, age);
String actNo = generateActNo();
Account act = new Account(actNo, "000000", 0.0);
user.addAct(act);
registUser(user);
printInfo();
}
}else if(comd.equals("2")||comd.equals("登录")){
System.out.println("请依次输入账号和密码：");
String actNo = sc.next();
String passwd = sc.next();
loginAct = login(actNo, passwd);
if(loginAct!=null){
while(true){
System.out.println("1.存款,2.取款,3.转账,4.余额,5.back");
String oper = sc.next();
if(oper.equals("1")||oper.equals("存款")){
System.out.println("请输入存款金额：");
double money = sc.nextDouble();
saveMoney(loginAct, money);
}else if(oper.equals("2")||oper.equals("取款")){
System.out.println("请输入取款金额：");
double money = sc.nextDouble();
getMoney(loginAct, money);
}else if(oper.equals("3")||oper.equals("转账")){
System.out.println("请输入转入账号：");
String inActNo = sc.next();
Account inAct = getActByNo(inActNo);
if(inAct!=null){
System.out.println("请输入转账金额：");
double money = sc.nextDouble();
transfer(loginAct, inAct, money);
}else{
System.out.println("转入账号不存在！");
}
}else if(oper.equals("4")||oper.equals("余额")){
System.out.println(loginAct.getActNo()+"账户余额为："+loginAct.getBalance()+"元！");
}else if(oper.equals("5")||oper.equals("back")){
break;
}else{
System.out.println("命令不合法！");
}
}
}else{
System.out.println("登录失败，请检查账号和密码后，重新登录！");
}
}else if(comd.equals("3")||comd.equals("退出")){
System.out.println("谢谢使用，系统退出！");
System.exit(0);
}else{
System.out.println("命令不合法！");
}
}
}
}
App
package ebank;
public class App {
public static void main(String[] args){
AccountService as = new AccountService();
as.run();
}
}
原文：http://www.cnblogs.com/Triste-qifei/p/4674939.html