java 日期天数计算的一些常用方法

/***

* 获取【查询时间】到现在多少天

*

* @param fromDate 查询时间

* @return

* @throws Exception

*/

public static int getDayFromCookiePlantTime(Date fromDate) {

Calendar cal = Calendar.getInstance();

cal.setTime(fromDate);

cal.set(Calendar.HOUR_OF_DAY, 0);

cal.set(Calendar.MINUTE, 0);

cal.set(Calendar.SECOND, 0);

Calendar now = Calendar.getInstance();

now.set(Calendar.HOUR_OF_DAY, 0);

now.set(Calendar.MINUTE, 0);

now.set(Calendar.SECOND, 0);

long interval = now.getTimeInMillis() - cal.getTimeInMillis();

long syts = interval / 60 / 60 / 1000 / 24;// 获取今天到指定日期剩余天数

return (int) syts;

}

/***

* 获取当前日期相隔天数的日期

*

* @param day

* @return

*/

public static String calendarDate(Date date, int day) {

Calendar cal = Calendar.getInstance();

cal.setTime(date);

cal.add(Calendar.DATE, day);

return formatDate(cal.getTime());

}

/***

* 给日期增加多少天

*

* @param calDate

* @param addDate 类型必须是long

* @return

*/

public static String addCalendarDay(Date calDate, long addDate) {

long time = calDate.getTime();

addDate = addDate * 24 * 60 * 60 * 1000;

time += addDate;

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

return dateFormat.format(new Date(time));

}