返回toString方法，而不是返回我想要的（Java）

Question

我有一个项目，其中我创建了一个BankAccount超级类和一个SavingsAccount子类。一切都很好，但我在返回我特别想要的字符串时遇到了麻烦。

示例：（裁剪）

public class BankAccount {
   public static final double MONTHS_IN_YEAR = 12.0;

   private String myCustomerName;
   private double myAccountBalance;
   private double myInterestRate;
   protected int myMonthlyWithdrawCount;
   protected double myMonthlyServiceCharges;

   public BankAccount(final String theNameOfOwner, 
                      final double theInterestRate) {
      myCustomerName = theNameOfOwner;
      myAccountBalance = 0.0;
      myInterestRate = theInterestRate;
      myMonthlyWithdrawCount = 0;
      myMonthlyServiceCharges = 0.0;
   }

   public String toString() {
      String result = "";
      result += String.format("BankAccount[owner: %s, balance: %.2f,",
                               myCustomerName, myAccountBalance);
      result += String.format(" interest rate: %.2f,", myInterestRate);
      result += String.format("\n\t\t  ");
      result += String.format("number of withdrawals this month: %d,",
                               myMonthlyWithdrawCount);
      result += String.format(" service charges for this month: %.2f]",
                               myMonthlyServiceCharges);
      return result;         
   }
}

驱动程序类将对BankAccount使用toString方法，并打印以下内容：

BankAccount[owner: John Doe, balance: 0.00, interest rate: 0.05,
          number of withdrawals this month: 0, service charges for this                month: 0.00] 

（这对于这个超类来说是完美的）

但是，下面是SavingsAccount子类

public class SavingsAccount extends BankAccount {
   public static final double SAVINGS_THRESHOLD = 25.0;

   private boolean myStatusIsActive;

   public SavingsAccount(final String theNameOfOwner, 
                         final double theInterestRate) {
      super(theNameOfOwner, theInterestRate);
      myStatusIsActive = false;
      if (super.getBalance() >= SAVINGS_THRESHOLD) {
         myStatusIsActive = true;
      }
   }

   public String toString() {
      String result = "";
      result += "SavingsAccount";
      result += super.toString();
      return result;
   }
}

调用SavingsAccount的toString方法时，它会打印：

SavingsAccountBankAccount[业主：Dan Doe，余额:0.00，利率:0.05，本月提款次数:0，本月服务费:0.00]

（我不希望包含bankaccount，我只希望它打印“savingsaccount”标头，然后直接转到“[owner:Dan Doe,”

我试着让它首先返回“savingsaccount”，这是正确的，但是当调用super.tostring（）时，它也返回了我不想要的bankaccount头。

我对如何解决这个问题有什么想法吗？

Answer 1

我能想到几个选择：

>

将“bankaccount”替换为“savingsaccount”，而不只是追加：

@Override
public String toString() {
    return super.toString().replaceFirst("BankAccount", "SavingsAccount");
}

将details部分移动到它自己的方法中，并从每个tostring()调用它，并使用适当的头：

// BankAccount.java
@Override
public String toString() {
    return "BankAccount" + getDetailsString();
}

protected String getDetailsString() {
    String result = String.format("[owner: %s, balance: %.2f,",
            myCustomerName, myAccountBalance);
    // ...
    return result;
}

// SavingsAccount.java
@Override
public String toString() {
    return "SavingsAccount" + getDetailsString();
}

@Override
public String toString() {
    String result = String.format("%s[owner: %s, balance: %.2f,",
            getClass().getSimpleName(), myCustomerName, myAccountBalance);
    // ...
    return result;
}