Calendar 的一些常见用法 如判断是否是同一天

1、Calendar 判断是否是同一天 代码如下 ：

思路 ：将两个Date 类型的时间格式化成Calendar 类型的时间 在分别获取两个事件的年月日  进行对比

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 计算 当前时间 已知当前日期

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";}

3、Calendar计算 一个月后的今天

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 ;}

4、两个时间相差多少

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;}