Question

我有一个项目，我正在创建一个带有SavingsAccount子类的BankAccount超级克拉。一切正常，但我无法返回我特别想要的字符串。

示例:(修剪下来）

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;         
   }
}

驱动程序类将使用BankAccount的toString方法并打印它：

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

（这对于这个超类非常适合）

但是，这里有子类SavingsAccount

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，会打印：

SavingsAccountBankAccount [所有者：Dan Doe，余额：0.00，利率：0.05，本月提款数量：0，本月服务费：0.00]

（我不想要包含BankAccount，我只是希望它打印＆＃34; SavingsAccount＆＃34;标题然后直接转到"[owner: Dan Doe," }

我试过让它回归＆＃34; SavingsAccount＆＃34;首先它正确地执行，但是当调用super.toString（）时，它也最终返回我不想要的BankAccount标题。

关于如何解决此问题的任何想法？

Answer 1

我能想到的一些选择：

将“BankAccount”替换为“SavingsAccount”，而不是仅仅添加它：

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

将详细信息部分移动到自己的方法中，并使用相应的标题从每个toString()调用它：

// 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();
}

在超类中获取运行时类名称，因此不需要完全覆盖它：

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

返回toString方法，不返回我想要的东西（Java）

1 个答案: