初学Java 使用输入对话框

 1 import javax.swing.JOptionPane;
 2 public class ComputeLoanUsingInputDialog {
 3   public static void main(String[] args) {
 4       String annualInterestRateString = JOptionPane.showInputDialog(
 5               "Enter yearly interest rate, for example 8.25:");
 6       
 7       double annualInterestRate =
 8               Double.parseDouble(annualInterestRateString);
 9       double monthlyInteresRate = annualInterestRate / 1200;
10       String numberOfYearsString = JOptionPane.showInputDialog(
11               "Enter number of years as an integer, \nfor example 5:");
12       
13       int numberOfYears = Integer.parseInt(numberOfYearsString);
14       String loanString = JOptionPane.showInputDialog(
15               "Enter loan amount, for example 120000.95:");
16       
17       double loanAmount = Double.parseDouble(loanString);
18       
19       double monthlyPayment = loanAmount * monthlyInteresRate / (1
20               - 1 / Math.pow(1 + monthlyInteresRate, numberOfYears * 12));
21       double totalPayment = monthlyPayment * numberOfYears * 12;
22       
23       monthlyPayment = (int)(monthlyPayment * 100) / 100.0;
24       totalPayment = (int)(totalPayment * 100) / 100.0;
25       
26       String output = "the monthly payment is " + monthlyPayment + 
27               "\nthe total payment is " + totalPayment;
28       JOptionPane.showMessageDialog(null, output);
29       
30   }
31 }