打印日历格式

package cn.com.test;

import java.util.Calendar;

import static java.lang.System.out;

public class Demo {
	static String[] MONTH = new String[]{"一月","二月","三月","四月","五月","六月","七月","八月","九月","十月","十一月","十二月"};
	static String[] WEEK = new String[]{"星期日","星期一","星期二","星期三","星期四","星期五","星期六"};

	/**
	 * 设置年月返回Calendar
	 * 
	 * @param year
	 * @param month
	 * @return
	 */
	public static Calendar getCalendar(int year, int month) {
		Calendar calendar = Calendar.getInstance();
		if (year != 0)
			calendar.set(Calendar.YEAR, year);
		if (month != 0)
			calendar.set(Calendar.MONTH, month-1);
		return calendar;
	}
	
	/**
	 * 设置年月返回year的上个月Calendar
	 * 
	 * @param year
	 * @param month
	 * @return
	 */
	public static Calendar getPreCalendar(int year, int month) {
		Calendar calendar = Calendar.getInstance();
		if (year != 0)
			calendar.set(Calendar.YEAR, year);
		if (month == 0)
			calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH));
		else
			calendar.set(Calendar.MONTH, month-2);
		return calendar;
	}
	
	/**
	 * 返回日历正式格式
	 * 
	 * @param year
	 * @param month
	 * @return
	 */
	public static Calendar getCalendarYM(int year,int month) {
		Calendar calendar =  getCalendar(year,month);
		//设置星期的第一天为星期天
		calendar.setFirstDayOfWeek(Calendar.SUNDAY);
		//设置每月的第一天
		calendar.set(Calendar.DAY_OF_MONTH,1);
		return calendar;
	}

	/**
	 * 打印日历格式
	 * 
	 * @param year
	 * @param month
	 */
	public static void printCalendar(int year,int month) {
		String[] days = new String[42];
		Calendar calendar = getCalendarYM(year, month);
		//第几天开始
		int firstDay = calendar.get(Calendar.DAY_OF_WEEK) - 1;
		//共几天
		int maxDays = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
		for (int i = 0; i < maxDays; i++) {
			days[firstDay + i] = String.valueOf(i + 1);
		}
		for(int i=0;i<WEEK.length;i++) {
			out.print("\t" + WEEK[i]);
		}
		out.println("\n");
		for(int j=0;j<6;j++) {
			for(int i=j*7;i<(j+1)*7;i++) { 
				out.print("\t" + (days[i]==null ? "" : days[i]));
			}
			out.println("\n");
		}
	}
	
	/**
	 * 打印日历格式
	 * 
	 * @param year
	 * @param month
	 * @param day
	 */
	public static void printCalendar(int year,int month,int day) {
		//总天数
		String[] days = new String[42];	
		
		Calendar dayCalendar = Calendar.getInstance();
		//当天
		int today = day;
		if(today == 0)
			today = dayCalendar.get(Calendar.DAY_OF_MONTH);
		
		Calendar calendar = getCalendarYM(year, month);
		//第几天开始
		int firstDay = calendar.get(Calendar.DAY_OF_WEEK) - 1;
		//共几天
		int maxDays = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
		
		//填充天数
		for (int i = 0; i < maxDays; i++) {
			days[firstDay + i] = String.valueOf(i + 1);
		}
		
		//上个月的最后几天
		Calendar preCalendar = getPreCalendar(year, month);
		int preMaxDays = preCalendar.getActualMaximum(Calendar.DAY_OF_MONTH);
		//后几天开始的下标
		int beginDay = firstDay - 1;
		//上个月的后几天信息
		Integer[] preDays = new Integer[firstDay];
		for(int i=0;i<preDays.length;i++) {
			preDays[i] = preMaxDays --;
		}
		//下个月的初始天
		int nextDay = 1;
		
		out.println("\t\t\t" + calendar.get(Calendar.YEAR)+"年"+(calendar.get(Calendar.MONTH)+1)+"月"+calendar.get(Calendar.DAY_OF_MONTH)+"日");
		for(int i=0;i<WEEK.length;i++) {
			out.print("\t" + WEEK[i]);
		}
		out.println("\n");
		
		for(int j=0;j<6;j++) {
			for(int i=j*7;i<(j+1)*7;i++) { 
				out.print("\t" +(days[i]==null ? (i<=firstDay ? preDays[beginDay--] : nextDay++) : (Integer.parseInt(days[i]) == today ? "*"+days[i] : days[i])));
			}
			out.println("\n");
		}
	}

	public static void main(String[] args) {
		printCalendar(0,6,0);
	}
}