java - 返回一个字符串供父类(super class)的抽象方法显示

Question

必须实现抽象方法statement(在父类(super class)中)才能返回语句的字符串表示形式。

所以我做了以下事情:

 public abstract String statement(); //The abstract method in my super class

..以及我的子类中的方法:

//@Override
public String statement() 
{
    return String.format("Account no %d has balance R%d and minimum balance R%d", accountNumber,balance,getMinBalance());
}

我的主类只是调用 Account 类(相关的父类(super class))，如下所示:

new SavingsAccount(Integer.toString(ao[i]),ao[i+1],ao[a]); //ao being the array which contains the values.

但是，控制台只是终止而不显示任何内容(我也不熟悉实现)。

完整代码如下:

主要:

public class AccountList 
{
    public static void main(String[] args) 
    {
        int[] ao = {00000,0,0,12345,500,250,23456,230,-50,34567,340,500,45678,-320,-50,56789,-320,-500};

        for(int i=0;i<ao.length;i=i+3)
        {
            int a = i+2;
            if(ao[a]>=0)
            {

                new SavingsAccount(Integer.toString(ao[i]),ao[i+1],ao[a]);
            }
            if(ao[a]<=0)
            {

                new ChequeAccount(Integer.toString(ao[i]),ao[i+1],ao[a]);
            }   
        }
    }
}

super 类:

public abstract class Account implements InterestAccount
{
    static String accountNumber;
    int balance;

    public Account()
    {
        accountNumber = "00000";
        balance = 0;
        //statement();
    }
    public Account(String accountNumber,int balance)
    {
        setAccountNum(accountNumber);
        setBalance(balance);
    }
    public void setAccountNum(String accNum)
    {
        accountNumber = accNum;
    }
    public void setBalance(int balance)
    {
        this.balance = balance;
    }
    public String getAccountNumber()
    {
        return accountNumber;
    }
    public int getBalance()
    {
        return balance;
    }
     public abstract String statement();
}

子类之一:

public class SavingsAccount extends Account
{
    int minBalance;

    public SavingsAccount()
    {
        super();
        minBalance = 0;
    }
    public SavingsAccount(String accountNum,int minBalance,int balance)
    {
        super(accountNum,balance);
        setMinBalance(minBalance);
    }
    public void setMinBalance(int minBalance)
    {
        this.minBalance = minBalance;
    }
    public int getMinBalance()
    {
        return minBalance;
    }
    @Override
    public int calculateInterest(int value) {

        if(minBalance>balance)
        {
            return 0;           
        }
        else
        {
            return (minBalance*balance)/100;
        }
    }
    //@Override
    public String statement() 
    {
        return String.format("Account no %d has balance R%d and minimum balance R%d", accountNumber,balance,getMinBalance());
    }

}

Answer 1

你永远不会调用方法语句。

1) 创建一个新的 SavingsAccount 对象

new SavingsAccount(Integer.toString(ao[i]),ao[i+1],ao[a]);

2)构造函数类被上述语句调用

public SavingsAccount(String accountNum,int minBalance,int balance)
{
    super(accountNum,balance);
    setMinBalance(minBalance);
}

3) 子类然后调用父类(super class)方法 公共(public)账户(String accountNumber,int 余额) { setAccountNum(帐号); 设置余额(余额)； }

4)调用SetBalance

public void setBalance(int balance)
{
    this.balance = balance;
}

5) setMinBalance 调用

public void setMinBalance(int minBalance)
{
    this.minBalance = minBalance;
}

6) 创建对象SavingsAccount结束

没有单个语句调用方法语句