java - 从ArrayList中获取特定元素

Question

我主要这样做:首先，我使用名字、姓氏和号码创建一个新客户。然后我创建两个 savingAccounts，及其金额、id 和利率。然后，我将两个 savingAccounts 添加到新客户。最后，我将新客户添加到银行。

Customer newCustomer = new Customer(firstName, lastName, pnumber);    

SavingsAccount savingsAccount1 = new SavingsAccount(400, "1", 4); //400$ into account no.1, with interest 4%
SavingsAccount savingsAccount2 = new SavingsAccount(300, "2", 3);

newCustomer.addAccount(savingsAccount1);  
newCustomer.addAccount(savingsAccount2);  

bank.addCustomer(newCustomer); 

这是银行类:

public class Bank {
    String bankName;    
    private ArrayList<Customer> customers = new ArrayList<Customer>(); 

    Bank(String bankName) {
        this.bankName = bankName;
    }

    public void addCustomer(Customer newCustomer) {
        customers.add(newCustomer);
    }
}

这是客户类:

public class Customer {
    private String firstName;
    private String lastName;
    private String number;      
    private ArrayList<Account> accounts;

    Customer(String firstName, String lastName, String number) { 
        this.firstName = firstName;
        this.lastName = lastName;
        this.number = number;
        this.accounts = new ArrayList<Account>();
    }

    public void addAccount(SavingsAccount account) {
        accounts.add(account);
    }

    public void addAccount(CreditAccount account) {
        accounts.add(account);
    }

    public ArrayList<Account> getAccounts() {
        return accounts;
    }
}

这里是 SavingsAccount 类(继承 Account 类):

public class SavingsAccount extends Account {

    public SavingsAccount() {     
        super();
    }

    public SavingsAccount(double bal, String id, double inte) {   
       super(bal, id, inte);
    }

    @Override
    public void deposit(String number, String id, double amount) {

    }

    @Override
    public void withdraw(String number, String id, double amount) {

    }

    @Override
    public void transfer(String number, String id, double amount) {

   }

    @Override  
    public double getBalance() {

    }

    @Override
    public String getAccountId() {
        return accountId;
    }

    @Override
    public double getInterest(){
        return interest;
    }
}

我的问题是:如何在 SavingsAccount 类中编写代码来为特定客户的特定帐户存款、取款、转账？假设我想在 2 号客户的 1 号账户上存入 500 美元。

应该类似于 savingAccount.deposit("2", "1", 500);

我只是不知道如何访问 2 号客户及其帐号 1。有人可以帮我吗？

Answer 1

您可以做的是在 Bank 类中有一个方法:

public class Bank {
  // Your stuff
  // new method:
  public boolean transfer(Account accountFrom, double amount, String nameTo, int account) {
     //check if the balance can be deposit from the account
     if(amount <= accountFrom.getBalance()) {
        //Check if the person exists in the bank
        String name = nameTo.split(" "); // name[0] is the first name, name[1] last name

        boolean success = false;
        for(Customer c: customers) {
           if(c.getFirstName().equalsIgnoreCase(name[0]) &&
                     c.getLastName().equalsIgnoreCase(name[1]) {
              for(Account a : c.getAccounts()) {
                 if(a.getAccountId() == account) {
                    // Add it to the account
                    a.deposit(amount);
                    success = true;
                    break;
                 }
              }
              break;
           }
        }

        // Deposit it from the account (That class should only keep track of money, so it 
        // only takes an argument to deposit or withdraw a value, the rest is done by the bank
        // Only do this if money has been dsposited at the target account
        if(success){
          accountFrom.withdraw(amount);
          return true;
        }

     }
     return false;
  }
}

要实现这一点，您必须从结构上改变您的设置。

让帐户仅管理资金，这些帐户将被添加到客户。客户是银行和他自己之间沟通的人。最后是银行与客户沟通。

希望这对您有所帮助