Java基本的程式設計結構（三）

（七）讀取輸入
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package readinput;

import javax.swing.JOptionPane;

/**
 *
 * @author vanessa
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        // get first input
      String name = JOptionPane.showInputDialog
         ("What is your name?");

      // get second input
      String input = JOptionPane.showInputDialog
         ("How old are you?");

      // convert string to integer value
      int age = Integer.parseInt(input);

      // display output on console
      System.out.println("Hello, " + name +
         ". Next year, you'll be " + (age + 1));

      System.exit(0);
    }

}
 

2，格式化輸出
NumberFormat.getCurrencyInstance()
NumberFormat.getPercentInstance()
NumberFormat.getNumberInstance()

static NumberFormat getCurrencyInstance()
// returns a NumberFormat object to convert currency values to strings using the conventions of the current locale.

static NumberFormat getNumberInstance()
// returns a NumberFormat object to format numbers using the conventions of the current locale.

static NumberFormat getPercentInstance()
// returns a NumberFormat object to convert percentages to strings.

String format(double number)
// returns a string that contains the formatted number.

void setMaximumFractionDigits(int digits)
// Parameters:
// Digits: the number of digits to display
// sets the maximum number of digits after the decimal point for the format object. The last
// displayed digit is rounded.

void setMaximumIntegerDigits(int digits)
// Parameters:
// Digits: the number of digits to display
// sets the maximum number of digits before the decimal point for the format object. Use this method with extreme caution. If you specify too few digits, then the number is simply truncated, displaying a dramatically wrong result!

void setMinimumFractionDigits(int digits)
// Parameters:
// Digits: the number of digits to display
// sets the minimum number of digits after the decimal point for the format object. If the number has fewer fractional digits than the minimum, then trailing zeroes are supplied.

void setMinimumIntegerDigits(int digits)
// Parameters:
// Digits: the number of digits to display
// sets the minimum number of digits before the decimal point for the format object. If the number has fewer digits than the minimum, then leading zeroes are supplied.