Question

给定帐户t，代码意味着为AccountA实例中的字段savingsAccount调用BankAccount方法getBalance。我尝试了各种执行此方法的方法。主要是后续的变化：

帐户t =新帐户（）;

吨

t.setSavingsAccount（new BankAccount（））;

的BankAccount @ XXXXXX

t.savingsAccount.getBalance（）;

静态错误：帐户中的任何字段都没有名称“savingsAccount”

如何重写此代码，以便将savingsAccount视为字段？是否有更好的方法从t？

中执行方法getBalance

相关守则：

    /**
 * A class to track an individuals bank portfolio.
 */
public class Account extends Object{
  private BankAccount savingsAccount = null;              //savings account identification number

 /**
   * A method to set account holder's savings account identification number.
   * @param savings account identification number
   * @return savings account identification number
   */
  public BankAccount setSavingsAccount(BankAccount input){
    savingsAccount = input;
    return savingsAccount;
  }

     /**
      * A method to return account holder's savingsaccount identification number.
      * @return savingsaccount identification number
      */
     public BankAccount getSavingsAccount(){
        return savingsAccount;
     }
    }

/**
 * A class to track the balance and terms of a bank account.
 */
public class BankAccount extends Object{
  private double currentBalance = 0;              //the balance of the account

 /**
  * Returns the balance of the account.
  * @param - void
  * @return the balance of the account
  */
  public double getBalance(){
    return currentBalance;
  }
    }

Answer 1

savingsAccount不是公共领域。您需要添加一个访问者方法（即getSavingsAccount()或将其公开。

Answer 2

正确的语法是

System.out.println(t.getSavingsAccount().getBalance());

从Java中的嵌入类调用方法

2 个答案: