Core Java (六) 列印指定月份的日曆

更改的core java的一個程式，利用了GregorianCalendar這個類。

輸入年份以及月份，列印出指定月份的日曆。

package com.xujin;import java.text.DateFormatSymbols;import java.util.Calendar;import java.util.GregorianCalendar;import java.util.Locale;import java.util.Scanner;public class Test {static Scanner cin = new Scanner(System.in);public static void main(String[] args){Locale.setDefault(Locale.US);//設定為美國地區System.out.print("Please input the year and month(like 1999 9):");int year = cin.nextInt();int month = cin.nextInt();GregorianCalendar day = new GregorianCalendar();//從公元 4 年 3 月 1 日之後是準確的//將day設定為該月的第一天day.set(Calendar.YEAR, year);day.set(Calendar.MONTH, month - 1);day.set(Calendar.DAY_OF_MONTH, 1);int weekday = day.get(Calendar.DAY_OF_WEEK);int firstDayOfWeek = day.getFirstDayOfWeek();int indent = 0;while(weekday != firstDayOfWeek){indent++;day.add(Calendar.DAY_OF_MONTH, -1);weekday = day.get(Calendar.DAY_OF_WEEK);}String[] weekdayNames = new DateFormatSymbols().getShortWeekdays();do{System.out.printf("%4s", weekdayNames[weekday]);day.add(Calendar.DAY_OF_MONTH, 1);weekday = day.get(Calendar.DAY_OF_WEEK);}while(weekday != firstDayOfWeek);System.out.println();for(int i = 0; i < indent; i++)System.out.print("    ");day.set(Calendar.DAY_OF_MONTH, 1);do{int d = day.get(Calendar.DAY_OF_MONTH);System.out.printf("%4s", d);day.add(Calendar.DAY_OF_MONTH, 1);weekday = day.get(Calendar.DAY_OF_WEEK);if(weekday == firstDayOfWeek) System.out.println();}while(month - 1 == day.get(Calendar.MONTH));if(weekday != firstDayOfWeek) System.out.println();}}

結果：