java日期加减年月日
/** * 日期相加减 * @param time * 时间字符串 yyyy-MM-dd HH:mm:ss * @param num * 加的数,-num就是减去 * @return * 减去相应的数量的年的日期 * @throws ParseException */ public static Date yearAddNum(Date time, Integer num) { //SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //Date date = format.parse(time); Calendar calendar = Calendar.getInstance(); calendar.setTime(time); calendar.add(Calendar.YEAR, num); Date newTime = calendar.getTime(); return newTime; } /** * * @param time * 时间 * @param num * 加的数,-num就是减去 * @return * 减去相应的数量的月份的日期 * @throws ParseException Date */ public static Date monthAddNum(Date time, Integer num){ //SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //Date date = format.parse(time); Calendar calendar = Calendar.getInstance(); calendar.setTime(time); calendar.add(Calendar.MONTH, num); Date newTime = calendar.getTime(); return newTime; } /** * * @param time * 时间 * @param num * 加的数,-num就是减去 * @return * 减去相应的数量的天的日期 * @throws ParseException Date */ public static Date dayAddNum(Date time, Integer num){ //SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //Date date = format.parse(time); Calendar calendar = Calendar.getInstance(); calendar.setTime(time); calendar.add(Calendar.DAY_OF_MONTH, num); Date newTime = calendar.getTime(); return newTime; }
/**
* 获取本月第一天时间
*/
public static Date getMonthStartDate(){
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH,1);
return calendar.getTime();
}
/**
* 获取本月最后一天
*
*/
public static Date getMonthEndDate(){
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
return calendar.getTime();
}
/**
* 获取本周的开始时间
*/
public static Date getBeginWeekDate(){
Calendar cal = Calendar.getInstance();
cal.setTime(new Date());
int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
//周日是1 ,周一是 2 ,周二是 3
//所以,当周的第一天 = 当前日期 - 距离周一过了几天(周一过了0天,周二过了1天, 周日过了6天)
// 2 - 周一的(dayofweek:2 )= 0
// 2 - 周二的(dayofweek:3 )= -1
// .
// .
// 2 - 周日的(dayofweek:1) = 1(这个是不符合的需要我们修改)===》2 - 周日的(dayofweek:1 ==》8 ) = -6
if (dayofweek == 1) {
dayofweek += 7;
}
cal.add(Calendar.DATE, 2 - dayofweek);
return cal.getTime();
}
/**
* 本周的结束时间
* 开始时间 + 6天
*/
public static Date getEndWeekDate(){
Calendar cal = Calendar.getInstance();
cal.setTime(new Date());
int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
if (dayofweek == 1) {
dayofweek += 7;
}
cal.add(Calendar.DATE, 8 - dayofweek);//2 - dayofweek + 6
return cal.getTime();
}