JAVA GUI浅谈：从输入对话框获取输入

import javax.swing.JOptionPane;

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

// Convert string to double
double annualInterestRate =
Double.parseDouble(annualInterestRateString);

// Obtain monthly interest rate
double monthlyInterestRate = annualInterestRate / 1200;

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

// Convert string to int
int numberOfYears = Integer.parseInt(numberOfYearsString);

// Enter loan amount
String loanString = JOptionPane.showInputDialog(
"Enter loan amount, for example 120000.95:");

// Convert string to double
double loanAmount = Double.parseDouble(loanString);

// Calculate payment
double monthlyPayment = loanAmount * monthlyInterestRate / (1
- 1 / Math.pow(1 + monthlyInterestRate, numberOfYears * 12));
double totalPayment = monthlyPayment * numberOfYears * 12;

// Format to keep two digits after the decimal point
monthlyPayment = (int)(monthlyPayment * 100) / 100.0;
totalPayment = (int)(totalPayment * 100) / 100.0;

// Display results
String output = "The monthly payment is " + monthlyPayment +
"\nThe total payment is " + totalPayment;
JOptionPane.showMessageDialog(null, output);
}
}