java计算2个时间相差的天数

public static int twoDaysDiffence(Calendar c1, Calendar c2) {
c1.add(Calendar.HOUR_OF_DAY, getCurTimeZoneDiffWithUTC());// 由于当前时区与格林威治时间所处时区不一致，所以需加上8小时
c2.add(Calendar.HOUR_OF_DAY, getCurTimeZoneDiffWithUTC());

long time1 = c1.getTimeInMillis() / MILLDAY;
long time2 = c2.getTimeInMillis() / MILLDAY;

return (int) (Math.abs(time1 - time2));
}

/** 获取当前时区与标准时区的时间差,单位小时(北京:8,韩国9) */
private static int getCurTimeZoneDiffWithUTC() {
return TimeZone.getTimeZone(TimeZone.getDefault().getID()).getRawOffset() / MILLHOUR;
}

private static final long MILLDAY = 24 * 60 * 60 * 1000l;