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  • Java中日期之Date

    1.获取两个Date之间的相差多少?(秒、分、时、天)

      try{
                SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    
                smdate=sdf.parse(sdf.format(smdate));
    
                bdate=sdf.parse(sdf.format(bdate));
    
                Calendar cal = Calendar.getInstance();
    
                cal.setTime(smdate);
    
                long time1 = cal.getTimeInMillis();
    
                cal.setTime(bdate);
    
                long time2 = cal.getTimeInMillis();
    
                long between_minutes=(time2-time1)/(1000*60);
    
               Integer.parseInt(String.valueOf(between_minutes));
            }catch (ParseException e){
                e.printStackTrace();
            }

    2.获取一天中的最开始时间

    try {
                SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                current = sdf.parse(sdf.format(current));
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(current);
                calendar.set(Calendar.HOUR_OF_DAY,0);
                calendar.set(Calendar.MINUTE,0);
                calendar.set(Calendar.SECOND,0);
                calendar.set(Calendar.MILLISECOND,0);
                Date dayStart = calendar.getTime();
                return dayStart;
            } catch (ParseException e) {
                e.printStackTrace();
            }

    3.获取一天中的最结束时间

    try {
                SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                current = sdf.parse(sdf.format(current));
                Calendar calendar = Calendar.getInstance();
                calendar.set(Calendar.HOUR_OF_DAY,23);
                calendar.set(Calendar.MINUTE,59);
                calendar.set(Calendar.SECOND,59);
                calendar.set(Calendar.MILLISECOND,999);
                Date dayEnd = calendar.getTime();
                return dayEnd;
            } catch (ParseException e) {
                e.printStackTrace();
            }

    4. LocalDateTime 转Date

    获取本月开始的时间(LocalDateTime)并转换成Date形式:

    public static LocalDateTime getFirstDayOfMonth() {
            LocalDateTime date = LocalDateTime.now();
            LocalDateTime firstday = date.with(TemporalAdjusters.firstDayOfMonth());
            return  LocalDateTime.of(firstday.toLocalDate(), LocalTime.MIN);
        }
    
     public static Date getDateByFirstDayOfMonth() {
            LocalDateTime minFirestDay =  getFirstDayOfMonth();
            ZoneId zoneId = ZoneId.systemDefault();
            ZonedDateTime zdt = minFirestDay.atZone(zoneId);
            return  Date.from(zdt.toInstant());
        }

     5.

    DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    LocalDate.now().format(dtf)

     6.LocalDate的常见用法:获取当前日期、获取指定日期、指定日期月最后一天、指定日期月有多少天:

    7.LocalDateTime指定日期格式,以及日期的相减:

     DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            String s = LocalDateTime.now().minusDays(1).format(dtf);

    当前日期:2020-07-20 14:33:18

    上述结果输出为:2020-07-19 14:28:18

    
    
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  • 原文地址:https://www.cnblogs.com/zhangshitong/p/12640070.html
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