用java完成一个简单的ATM项目

       首先要了解的是，这个ATM项目本身是一个轻量级的项目，只为了完成一些ATM具备的一些方法，并非是真正完成一个ATM的全部功能和需求

       那么在这个轻量级的ATM项目中，我将完成添加储蓄账号，添加信用账户，提款，取款等基本功能。

       适合新手查看，需要掌握java的继承，多态，封装等基本技术能力

      那么，首先创建如下的对象类：Account（账户类），Bank（银行类），CreditAccount（信用账户），SavingAccount（储蓄账户类）；

大家首先应该搞清楚，这些类文件中之间的关系，每个类之间需要用到什么样的方法；

那么我们先填写Account类

package com.atm.entity;/** * 银行账户类 */public abstract class Account {/** * 账户帐号 */private String accountId;/** * 账户姓名 */private String accountName;/** * 账户密码 */private String accountPwd;/** * 账户余额 */private double accountBalance;/** * 账户身份证号 */private String accountPersonId;/** * 账户邮箱 */private String accountEmail;/** * 账户联系电话 */private long accountTelno;public Account() {}public Account(String accountName, String accountPwd, String accountPersonId, long accountTelno,String accountEmail) {this.accountName = accountName;this.accountPwd = accountPwd;this.accountPersonId = accountPersonId;this.accountTelno = accountTelno;this.accountEmail = accountEmail;}public String getAccountId() {return accountId;}public void setAccountId(String accountId) {this.accountId = accountId;}public String getAccountName() {return accountName;}public void setAccountName(String accountName) {this.accountName = accountName;}public String getAccountPwd() {return accountPwd;}public void setAccountPwd(String accountPwd) {this.accountPwd = accountPwd;}public double getAccountBalance() {return accountBalance;}public void setAccountBalance(double accountBalance) {this.accountBalance = accountBalance;}public String getAccountPersonId() {return accountPersonId;}public void setAccountPersonId(String accountPersonId) {this.accountPersonId = accountPersonId;}public String getAccountEmail() {return accountEmail;}public void setAccountEmail(String accountEmail) {this.accountEmail = accountEmail;}public long getAccountTelno() {return accountTelno;}public void setAccountTelno(long accountTelno) {this.accountTelno = accountTelno;}/** * 存款 *  * @param money *            存款金额 * @return 返回账户余额 */public double depoist(double money) {// money 形式参数if (money > 0)this.accountBalance += money;return this.accountBalance;}/** * 取款 *  * @param money *            取款金额 * @return 返回账户余额 */public abstract double withdraw(double money);/** * 转账 *  * @param anotherAccount *            转账的对方账户 * @param money *            转账金额 * @return 返回当前账户的余额 */public double tranferAccount(Account anotherAccount, double money) {// 形参anotherAccount.accountBalance += money;this.accountBalance -= money;return this.accountBalance;}}

之后填写信用账户类CreditAccount；我们应该明白，他是继承Account类的，但是，他又需要拥有自身独立的属性，我们可以添加一个最高透支额度的属性

这样来实现代码

/** * 信用账户 *  * */public class CreditAccount extends Account  {//成员变量private double maxOverdraw;//最高透支额度//构造函数public CreditAccount(String accountName,String accountPwd,String accountPersonId,long accountTelno,String accountEmail,double maxOverdraw){super( accountName, accountPwd, accountPersonId, accountTelno, accountEmail);this.maxOverdraw  =  maxOverdraw;}//set,getpublic void setMaxOverdraw(double maxOverdraw ){this.maxOverdraw = maxOverdraw;}public double getMaxOverdraw(){return this.maxOverdraw;}@Overridepublic double withdraw(double money) {// TODO Auto-generated method stubreturn 0;}}

同理  填写储蓄账户（SavingAccount）类文件

package com.atm.entity;/** * 储蓄账户 *  * */public class SavingAccount extends Account {public SavingAccount(String accountName,String accountPwd,String accountPersonId,long accountTelno,String accountEmail){super( accountName, accountPwd, accountPersonId, accountTelno, accountEmail);}@Overridepublic double withdraw(double money) {// TODO Auto-generated method stubif(money <= getAccountBalance()){}elseSystem.out.println("账户余额不足");return getAccountBalance();}}

最重要的是填写Bank类的内容，在这个类中，我们要完成注册，产生银行账户，统计所有信用账户的最高透支额度的总和，统计所有账户的总余额， 查询出所有信用账户中透支额度最高的账户， 查询出所有储蓄账户中余额最高的账户等功能

我们这样填写

       

package com.atm.entity;import java.text.SimpleDateFormat;import java.util.Date;/** * 银行类 *  * @author qianghj *  *         银行开户 ----> 银行账户 Account account = bank.开户(...) * */public class Bank {public Account[] accArray = new Account[2000];public int count = 0;// 表示银行账户的个数/** * 银行账户开户 *  * @param accName *            用户名称 * @param accPwd *            用户密码 * @param accPersonId *            用户身份证 * @param accTelno *            用户手机号码 * @param accEmail *            用户邮箱 * @param accountType *            账户类型 0： 储蓄账户 1 ： 信用账户 * @param maxOverdraw *            信用账户的最高透支额度 * @return 返回有效的银行账户 */public Account registAccount(String accName, String accPwd, String accPersonId, long accTelno, String accEmail,int accountType, double maxOverdraw) {Account account = null;if (accountType == 0)account = new SavingAccount(accName, accPwd, accPersonId, accTelno, accEmail);elseaccount = new CreditAccount(accName, accPwd, accPersonId, accTelno, accEmail, maxOverdraw);account.setAccountId(generateNextAccountId());accArray[count++] = account;return account;}/** * 产生银行账户帐号 *  * @return 返回下一个账户的帐号 1，2，3，，4 */public String generateNextAccountId() {return "62223421" + new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date());}// 统计所有信用账户的最高透支额度的总和 （1050 ） 2000 , 1050public double statisticsCreditAccountMaxoverdrawSum() {double sum = 0;for (int i = 0; i < count; i++) {// 判断账户 是不是 CreditAccount类型if (accArray[i] instanceof CreditAccount) {CreditAccount creditAcc = (CreditAccount) accArray[i];sum += creditAcc.getMaxOverdraw();}}return sum;}// 统计所有账户的总余额public double aggregateAamount() {double sum = 0;for (int i = 0; i < count; i++) {if (accArray[i] instanceof SavingAccount) {SavingAccount savingAccount = (SavingAccount) accArray[i];sum += savingAccount.getAccountBalance();}}return sum;}// 查询出所有信用账户中透支额度最高的账户public double maxLimit() {double tem = 0;for (int i = 0; i < count; i++) {if (accArray[i] instanceof CreditAccount) {CreditAccount creditAccount = (CreditAccount) accArray[i];if (creditAccount.getMaxOverdraw() > tem) {tem = creditAccount.getMaxOverdraw();}}}return tem;}// 查询出所有储蓄账户中余额最高的账户public double maxBalance() {double tem = 0;for (int i = 0; i < count; i++) {if (accArray[i] instanceof SavingAccount) {SavingAccount savingAccount = (SavingAccount) accArray[i];if (savingAccount.getAccountBalance() > tem) {tem = savingAccount.getAccountBalance();}}}return tem;}}

最后测试类

package test;import org.junit.Test;import com.atm.entity.Account;import com.atm.entity.Bank;import com.atm.entity.CreditAccount;public class TestAccount {@Testpublic void testRegist() {Bank bank = new Bank();for (int i = 0; i < 1000; i++) {// 0： 储蓄账户 1 ： 信用账户Account acc = bank.registAccount("tom" + i, "abc123", "2729382932", 183923302L, "tom" + i + "@163.com",i % 2, (i % 2 == 0) ? 0 : 3000);if (i % 2 != 0) {CreditAccount creditAcc = (CreditAccount) acc;System.out.println("所有信用账户的名字：" + creditAcc.getAccountName() + "和透支额度:" + creditAcc.getMaxOverdraw());}}// 1000个银行账户开户，500是信用账户，最高透支额度随机数赋值，再测试// double sum = bank.统计所有信用账户的最高透支额度的总和 ();double sum = bank.statisticsCreditAccountMaxoverdrawSum();System.out.println("所有信用账户的最高透支额度的总和 :" + sum);double sum1 = bank.aggregateAamount();System.out.println("总余额为" + sum1);}}

测试类的内容不多写，大家有兴趣可以自行测试。这样，我们就完成了一个比较简单的ATM项目。希望对新学者有所帮助