如何计算两个转换为双精度的字符串 [duplicate]

问：

我是 Java 的新手，正在尝试编写一个程序，询问您的姓名、收入、美联储和州税率，然后计算您应该缴纳多少税款。它应该包括对话框。我的问题是这样的：我已经完成了所有代码并放入了parseDouble（）方法，但是当我去计算时，Eclipse给了我错误（stateTaxRate无法解析为变量，并且它也对fedTaxRate变量做同样的事情！我超级卡住了。

import javax.swing.JOptionPane;
public class FedAndStateTaxes {


  public static void main(String[] args) {
    
    String yourName= JOptionPane.showInputDialog("What is your name?");
    JOptionPane.showMessageDialog(null, "Name: " + yourName);
    
    
    String yearlyIncome = JOptionPane.showInputDialog("What is your yearly income?");

    
    try {double num = Double.parseDouble(yearlyIncome); 
    JOptionPane.showMessageDialog(null, "Yearly Income: "+ num);
    
    }
    catch(NumberFormatException e){
    JOptionPane.showMessageDialog(null,"Error. Number input only please.");
    }
    
    
    String fTaxRate = JOptionPane.showInputDialog("Please enter your federal tax rate");
    
    
    try { double fedTaxRate = Double.parseDouble(fTaxRate);
    JOptionPane.showMessageDialog(null, "Federal Tax Rate: " + fedTaxRate +"%");
        
    }
    catch(NumberFormatException e){
        JOptionPane.showMessageDialog(null, "Error. Number input only please.");
    }
    
    String sTaxRate = JOptionPane.showInputDialog("Pleae enter your state tax rate");
    
    try { 
        double stateTaxRate = Double.parseDouble(sTaxRate);
        JOptionPane.showMessageDialog(null, "State Tax Rate: " + stateTaxRate + "%");
    }
    catch(NumberFormatException e) {
        JOptionPane.showMessageDialog(null,"Error. Number input only please");
    }
    


    double calculateIncome = (stateTaxRate);
    

我尝试在parseDouble（）方法中更改参数/变量名称。我希望它会回调到我转换为双精度的字符串变量，但它无法解析。