Question

我正在尝试创建一个银行帐户程序，用户可以在其中输入储蓄帐户的“ s”或“ S”帐户类型。他们还可以为支票帐户输入“ c”或“ C”。我在让用户输入通过getter / setter方法运行，然后在输出中根据输入返回字符串“ Savings”或“ Checking”时遇到问题。

package com.company;
import javax.swing.*;

public class Main {

    public static void main(String[] args) {

        BankAccount myBank = new BankAccount();

        myBank.setAccountType(JOptionPane.showInputDialog("please enter an account type"));
            JOptionPane.showMessageDialog(null, "Account Number: " + "\nAccount Type: " + myBank.getAccountType() +"\nMinimum Balance: "+ "\nBalance Before Interest and Fees: " + "\n\nNew Balance:\n");

    }
}

BankAccount类

package com.company;

public class BankAccount  {
    private int accountNumber;
    private String accountType;
    private double minSavings = 2500;
    private double minChecking = 1000;
    private double currentBalance;


    public BankAccount(){ }

    public String getAccountType () {
        return this.accountType;
    }

    public void setAccountType (String please_enter_an_account_type) {
        if (accountType == "S" || accountType == "s")  {
            this.accountType = "Savings";
        }

        else if (accountType == "C" || accountType == "c")  {
            this.accountType = "Checking";
        }

    }
}

Answer 1

您的setAccountType方法代码应如下所示：

public void setAccountType (String accountType)
        {
            if (accountType.equalsIgnoreCase("S"))
            {
                this.accountType = "Savings";
            }

            else if (accountType.equalsIgnoreCase("C"))
            {
                this.accountType = "Checking";
            }

        }

这将解决问题。

参考：== and equals()之间的区别： What is the difference between == vs equals() in Java?

我已经使用equalsIgnoreCase()来检查小写和大写值。

Answer 2

String是一个Java对象，使用==运算符比较两个Java对象引用仅在两个引用都引用同一对象时才返回true。这里if中的“ s”和setter中的输入字符串“ s”指的是不同的对象。因此，要使其正常工作，您需要使用String的equals方法，该方法比较值而不是对象参考。

 public void setAccountType (String accountType)
        {
            if (accountType.toLowerCase().equals("s"))
            {
                this.accountType = "Savings";
            }

            else if (accountType.toLowerCase().equals("c"))
            {
                this.accountType = "Checking";
            }

        }

如何在getter和setter方法中正确使用if else语句？

2 个答案: