/**
* @author xzy
* @date 2020-09-14 14:05
* 说明：日期处理
*/
public class CalendarUtils {
/**
* Get a instance of Calendar by given Date instance.
*
* @param date the date want to convert
* @return a instance of Calendar by given Date instance
*/
public static Calendar date2Calendar(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return calendar;
}
/**
* Get a instance of Date by given Calendar instance.
*
* @param calendar the calendar want to convert
* @return a instance of Date by given Calendar instance.
*/
public static Date calendar2Date(Calendar calendar) {
return calendar.getTime();
}
/**
* Get the day of the week represented by this date.
*
* @param date -
* @return 0：Sunday 1：Monday 2：Tuesday 3：Wednesday 4：Thursday 5：Friday 6：Saturday
*/
public static int getDayOfWeek(Date date) {
Calendar calendar = date2Calendar(date);
return calendar.get(Calendar.DAY_OF_WEEK);
}
/**
* Get the day of the year represented by this date.
*
* @param date -
* @return the day of the year represented by this date.The first day of the year has value 1.
*/
public static int getDayOfYear(Date date) {
Calendar calendar = date2Calendar(date);
return calendar.get(Calendar.DAY_OF_YEAR);
}
/**
* 计算两个日期间相差的天数。
*
* @param date1 - 日期1
* @param date2 - 日期2
* @return - 两个日期相差的天数。注意，本方法认为 “2020-01-01 23:59:59” 与 “2020-01-02 00:00:00”相差1天。
*/
public static long getDaysOfDifference(Date date1, Date date2) {
if (date1 == null || date2 == null) {
throw new NullPointerException();
}
return getDaysOfDifference(date2Calendar(date1), date2Calendar(date2));
}
/**
* 计算两个日期间相差的天数。
*
* @param cal1 - 日期1
* @param cal2 - 日期2
* @return - 两个日期相差的天数。注意，本方法认为 “2020-01-01 23:59:59” 与 “2020-01-02 00:00:00”相差1天。
*/
public static long getDaysOfDifference(Calendar cal1, Calendar cal2) {
if (cal1 == null || cal2 == null) {
throw new NullPointerException();
}
cleanTime(cal1);
cleanTime(cal2);
// 1天 = 24小时 = 24*3600秒 = 24*3600*1000毫秒
long dayOfDifference = (cal1.getTimeInMillis() - cal2.getTimeInMillis()) / (1000 * 3600 * 24);
dayOfDifference = dayOfDifference < 0 ? -dayOfDifference : dayOfDifference;
return dayOfDifference;
}
/**
* Returns whether the two dates are the same day.
*
* @param date1 the date 1
* @param date2 the date 2
* @return whether the two dates are the same day.
*/
public static boolean isSameDay(Date date1, Date date2) {
if (date1 == null || date2 == null) {
throw new NullPointerException();
}
return isSameDay(date2Calendar(date1), date2Calendar(date2));
}
/**
* Returns whether the two dates are the same day.
*
* @param cal1 the date 1
* @param cal2 the date 2
* @return whether the two dates are the same day.
*/
public static boolean isSameDay(Calendar cal1, Calendar cal2) {
if (cal1 == null || cal2 == null) {
throw new NullPointerException();
}
return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
}
/**
* 清洗时间——将时、分、秒、毫秒清零
*
* @param calendar - 待处理的日期
*/
public static void cleanTime(Calendar calendar) {
if (calendar == null) {
throw new IllegalArgumentException("The date must not be null");
}
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
}
public static Date cleanTime(Date date) {
Calendar calendar = date2Calendar(date);
cleanTime(calendar);
return calendar2Date(calendar);
}
/**
* 清除日期——将年、月、日清零
*
* @param calendar - 待处理的日期
*/
public static void cleanDate(Calendar calendar) {
if (calendar == null) {
throw new IllegalArgumentException("The date must not be null");
}
calendar.set(Calendar.YEAR, 0);
calendar.set(Calendar.MONTH, 0);
calendar.set(Calendar.DAY_OF_MONTH, 0);
}
public static Date cleanDate(Date date) {
Calendar calendar = date2Calendar(date);
cleanDate(calendar);
return calendar2Date(calendar);
}
/**
* 获取指定日期的“最初时刻”，即“yyyy-MM-dd 00:00:00:000”
*
* @param calendar - 待处理的日期
*/
public static void firstMoment(Calendar calendar) {
cleanTime(calendar);
}
public static Date firstMoment(Date date) {
Calendar calendar = date2Calendar(date);
firstMoment(calendar);
return calendar2Date(calendar);
}
/**
* 获取指定日期的“最终时刻”，即“yyyy-MM-dd 23:59:59:999”
*
* @param calendar - 待处理的日期
*/
public static void lastMoment(Calendar calendar) {
if (calendar == null) {
throw new IllegalArgumentException("The date must not be null");
}
calendar.set(Calendar.HOUR_OF_DAY, 23);
calendar.set(Calendar.MINUTE, 59);
calendar.set(Calendar.SECOND, 59);
calendar.set(Calendar.MILLISECOND, 999);
}
public static Date lastMoment(Date date) {
Calendar calendar = date2Calendar(date);
lastMoment(calendar);
return calendar2Date(calendar);
}
/**
* 按照日期的计算规则，将指定日期的指定字段加上或减去指定的量。
*
* @param date - 待修改的日期
* @param field - 待修改的日期字段（具体取值需要查询Calendar接口）
* @param amount - 修改量
* @return - 修改后的日期
*/
public static Date add(Date date, int field, int amount) {
if (date == null) {
throw new IllegalArgumentException("The date must not be null");
}
Calendar calendar = date2Calendar(date);
calendar.add(field, amount);
return calendar2Date(calendar);
}
private CalendarUtils() {
}
}