Java 银行计划。如何让客户拥有多个账户？
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Java Bank program. How to let customer have multiple accounts?
提问by user2939293
I'm making a bank program in java and have 5 classes: Account, SavingsAccount (inherits Account), CreditAccount (inherits Account), Bank, Customer.
我正在用 java 制作一个银行程序，有 5 个类：帐户、储蓄帐户（继承帐户）、信用帐户（继承帐户）、银行、客户。
The program is working as it is, but I can't figure out how to make a customer have two or more accounts. Lets say that one customer wants both a credit account AND a savings account, or maybe two savings accounts.
该程序按原样运行，但我不知道如何让客户拥有两个或多个帐户。假设一个客户想要一个信用账户和一个储蓄账户，或者可能是两个储蓄账户。
Can anyone give me some suggestions? Thank you
谁能给我一些建议？谢谢
Bank class:
银行类：
public class Bank {
String bankName;
private Customer[] customers = new Customer[100];
Bank(String bankName) {
this.bankName = bankName;
}
public Customer[] getCustomer() {
return customers;
}
public String getBankname() {
return bankName;
}
}
Account class:
账户类：
public abstract class Account {
protected double balance = 0;
protected String accountId;
public Account() {} //Defaultkonstruktor
public Account(double bal, String id) { //Konstruktor
if (balance >= 0) {
balance = bal;
}
else {
balance = 0;
}
accountId = id;
}
public abstract void deposit(double amount);
public abstract void withdraw(double amount);
public abstract double getBalance();
public abstract String getAccountId();
public abstract void transfer(double amount, Account account);
}
SavingsAccount class: (CreditAccount class is similar)
SavingsAccount 类：（CreditAccount 类类似）
public class SavingsAccount extends Account{
private double interest = 2.9;
public SavingsAccount() { //Konstruktor
super();
}
public SavingsAccount(double balance, String id) { //Konstruktor
super(bal,id);
}
public void setInterest(Customer customer) {
//code
}
public void setBalance(double balance) {
//code
}
@Override
public void deposit(double amount) {
//code
}
@Override
public void withdraw(double amount) {
//code
}
@Override
public double getBalance(){
//code
}
@Override
public String getAccountId(){
//code
}
@Override
public void transfer(double amount, Account account) {
//code
}
public void setInterest(double interest){
//code
}
public double getInterest(){
//code
}
}
Customer class:
客户类别：
public class Customer {
private String firstName;
private String lastName;
private String number;
private SavingsAccount account = new SavingsAccount();
private CreditAccount cAccount = new CreditAccount();
Customer(String firstName, String lastName, String number, SavingsAccount account) {
this.firstName = firstName;
this.lastName = lastName;
this.number = number;
this.account = account;
}
Customer(String firstName, String lastName, String number, CreditAccount cAccount) {
this.firstName = firstName;
this.lastName = lastName;
this.number = number;
this.cAccount = cAccount;
}
public SavingsAccount getAccount() {
return account;
}
public CreditAccount getCreditAccount() {
return cAccount;
}
}
Main:
主要的：
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int choice;
int numberOfCustomers = 0;
boolean endProgram = false;
String bankName;
System.out.print("Name of bank: ");
bankName = input.next();
Bank bank = new Bank(bankName);
String accountId;
SavingsAccount acc = new SavingsAccount();
Customer[] customer = bank.getCustomer();
do {
System.out.println(" " + bank.getBankname() + "\n");
System.out.println(" 1. See balance ");
System.out.println(" 2. Withdraw ");
System.out.println(" 3. Deposit ");
System.out.println(" 4. Transfer ");
System.out.println(" 5. Add interest ");
System.out.println(" 6. Add new customer ");
System.out.println(" 7. Show customers ");
System.out.println(" 8. Change interest ");
System.out.println(" 0. Exit ");
choice = input.nextInt();
switch(choice) {
case 1:
//code
break;
case 2:
//code
break;
case 3:
//code
break;
case 4:
//code
break;
case 5:
//code
break;
case 6: //Add customer
System.out.println("Choose account: ");
System.out.println("1. Savings account");
System.out.println("2. Credit account");
choice = input.nextInt();
switch(choice) {
case 1: //Create savings account
System.out.print("Enter amount to deposit: ");
double amount = input.nextDouble();
System.out.println("Account number is: " + numberOfCustomers);
SavingsAccount savingsAccount = new SavingsAccount(amount, String.valueOf(numberOfCustomers));
System.out.print("First name: ");
String firstName = input.next();
System.out.print("Last name: ");
String lastName = input.next();
System.out.print("Customer number: ");
String pnumber = input.next();
Customer newCustomer = new Customer(firstName, lastName, pnumber, savingsAccount);
customer[numberOfCustomers] = newCustomer;
numberOfCustomers++;
break;
case 2: //Create credit account
System.out.print("Enter amount to deposit: ");
double amount = input.nextDouble();
System.out.println("Account number is: " + numberOfCustomers);
CreditAccount creditAccount = new CreditAccount(amount, String.valueOf(numberOfCustomers));
System.out.print("First name: ");
String firstName = input.next();
System.out.print("Last name: ");
String lastName = input.next();
System.out.print("Customer number: ");
String pnumber = input.next();
Customer newCustomer = new Customer(firstName, lastName, pnumber, creditAccount);
customer[numberOfCustomers] = newCustomer;
numberOfCustomers++;
break;
}
break;
case 7:
//code
break;
case 8:
//code
break;
case 0:
//code
break;
}
} while (!endProgram);
}
回答by emeraldjava
First off rename Account to AbstractAccount and create an Account interface, your Credit and Saving accounts are concrete implementations. Then in your Customer class declare a variable accounts which is a List accounts. Something like
首先将 Account 重命名为 AbstractAccount 并创建一个 Account 接口，您的 Credit 和 Saving 帐户是具体实现。然后在您的 Customer 类中声明一个变量帐户，它是一个列表帐户。就像是
public class Customer {
private String firstName;
private String lastName;
private String number;
private List<Account> accounts;
Your Account interface might look like
您的帐户界面可能看起来像
interface Account {
public void deposit(double amount);
public void withdraw(double amount);
public double getBalance();
public String getAccountId();
}
Your existing class gets refactored
您现有的类被重构
public abstract AbstractAccount implements Account {
....
}
Your SavingAccount becomes
您的 SavingAccount 变为
public SavingAccount extends AbstractAccount {
....
}
I'd be a little worried that this method is declared as abstract on the Account class. Why would a transfer be implemented differently on two different classes?
我有点担心这个方法在 Account 类上被声明为抽象的。为什么在两个不同的类上会以不同的方式实现传输？
public abstract void transfer(double amount, Account account);
I suggest this method would be belong more to an AccountManager class which would ensure the correct amount is credited/debited from two accounts.
我建议这个方法更多地属于 AccountManager 类，它可以确保从两个帐户中贷记/借记正确的金额。
public void transfer(double amount, Account fromAccount, Account toAccount);
This class could then check that the 'fromAccount' has the required funds available to transfer as a validation step before the actual transfer happens.
然后，此类可以检查“fromAccount”是否具有可用于转移的所需资金，作为在实际转移发生之前的验证步骤。
回答by tomer
Instead of get to Customer's object constructor SavingsAccount or CreditAccount, you may use:
您可以使用：
Customer(String firstName, String lastName, String number) {
...
}
And add set method to account and cAccount:
并向 account 和 cAccount 添加 set 方法：
Public void setAccount(SavingAccount account) {
This.account = account;
}
of course you could create a list like in the previous comment:
当然，您可以像之前的评论一样创建一个列表：
and add method:
并添加方法：
public void addAccount(Account account) {
accounts.add(account);
}
