初学Java 使用输入对话框

 import javax.swing.JOptionPane;
 public class ComputeLoanUsingInputDialog {
   public static void main(String[] args) {
       String annualInterestRateString = JOptionPane.showInputDialog(
               "Enter yearly interest rate, for example 8.25:");

       double annualInterestRate =
               Double.parseDouble(annualInterestRateString);
       double monthlyInteresRate = annualInterestRate / ;
       String numberOfYearsString = JOptionPane.showInputDialog(
               "Enter number of years as an integer, \nfor example 5:");

       int numberOfYears = Integer.parseInt(numberOfYearsString);
       String loanString = JOptionPane.showInputDialog(
               "Enter loan amount, for example 120000.95:");

       double loanAmount = Double.parseDouble(loanString);

       double monthlyPayment = loanAmount * monthlyInteresRate / (
               -  / Math.pow( + monthlyInteresRate, numberOfYears * ));
       double totalPayment = monthlyPayment * numberOfYears * ;

       monthlyPayment = (int)(monthlyPayment * ) / 100.0;
       totalPayment = (int)(totalPayment * ) / 100.0;

       String output = "the monthly payment is " + monthlyPayment +
               "\nthe total payment is " + totalPayment;
       JOptionPane.showMessageDialog(null, output);

   }
 }