打印日历

package calendar;

import java.text.DateFormatSymbols;

import java.util.*;

/**

* @version 1.4 2007-04-07

* @author Cay Horstmann

*/

public class CalendarTest

{

public static void main(String[] args)

{

// construct d as current date

GregorianCalendar d = new GregorianCalendar();

int today = d.get(Calendar.DAY_OF_MONTH);

int month = d.get(Calendar.MONTH);

// set d to start date of the month

d.set(Calendar.DAY_OF_MONTH, 1);

int weekday = d.get(Calendar.DAY_OF_WEEK);

// get first day of week (Sunday in the U.S.)

int firstDayOfWeek = d.getFirstDayOfWeek();

// determine the required indentation for the first line

int indent = 0;

while (weekday != firstDayOfWeek)

{

indent++;

d.add(Calendar.DAY_OF_MONTH, -1);

weekday = d.get(Calendar.DAY_OF_WEEK);

}

// print weekday names

String[] weekdayNames = new DateFormatSymbols().getShortWeekdays();

do

{

System.out.printf("%4s", weekdayNames[weekday]);

d.add(Calendar.DAY_OF_MONTH, 1);

weekday = d.get(Calendar.DAY_OF_WEEK);

}

while (weekday != firstDayOfWeek);

System.out.println();

for (int i = 1; i <= indent; i++)

System.out.print(" ");

d.set(Calendar.DAY_OF_MONTH, 1);

do

{

// print day

int day = d.get(Calendar.DAY_OF_MONTH);

System.out.printf("%5d", day);

// mark current day with *

if (day == today) System.out.print("*");

else System.out.print(" ");

// advance d to the next day

d.add(Calendar.DAY_OF_MONTH, 1);

weekday = d.get(Calendar.DAY_OF_WEEK);

// start a new line at the start of the week

if (weekday == firstDayOfWeek) System.out.println();

}

while (d.get(Calendar.MONTH) == month);

// the loop exits when d is day 1 of the next month

// print final end of line if necessary

if (weekday != firstDayOfWeek)

System.out.println();

}

}