1、Calendar 判斷是否是同一天 程式碼如下 ：

思路 ：將兩個Date 型別的時間格式化成Calendar 型別的時間 在分別獲取兩個事件的年月日  進行對比

	public static boolean isSameDay(Date date1, Date date2) {
		Calendar calDateA = Calendar.getInstance();
		calDateA.setTime(date1);

		Calendar calDateB = Calendar.getInstance();
		calDateB.setTime(date2);

		return calDateA.get(Calendar.YEAR) == calDateB.get(Calendar.YEAR)
				&& calDateA.get(Calendar.MONTH) == calDateB.get(Calendar.MONTH)
				&& calDateA.get(Calendar.DAY_OF_MONTH) == calDateB
						.get(Calendar.DAY_OF_MONTH);
	}
 

2、Calendar 計算 當前時間 已知當前日期

	public static String getYearAndMonthDay(int dayofMonth) {
		Calendar rightNow = Calendar.getInstance();
		Date today = new Date(System.currentTimeMillis());
		rightNow.setTime(today);
		rightNow.add(Calendar.MONTH, 1); //rightHow.add(Calendar.MONTH,1)
			return (rightNow.get(Calendar.YEAR)+"年"+rightNow.get(Calendar.MONTH)) + "月" + dayofMonth + "日";
	}
	
 

	public static String getNextDate(int dayofMonth) {
		Calendar rightNow = Calendar.getInstance();
		Date today = new Date(System.currentTimeMillis());
		rightNow.setTime(today);
		int day = rightNow.get(Calendar.DAY_OF_MONTH+1);
			return rightNow.get(Calendar.YEAR) +"-"+(rightNow.get(Calendar.MONTH) + 2) + "-" + dayofMonth ;
	}
 

	public static final int getDayFromTimeDiff(Date d1, Date d2) {
		if (d1 == null || d2 == null) {
			return 0;
		}
		long l1 = d1.getTime();
		long l2 = d2.getTime();
		long diff = l2 - l1;
		int day = (int) (diff / (1000 * 3600 * 24));
		return day;
	}