将Julian日期转换为常规日历日期

Question

如何将7位朱利安日期转换为MM/dd/yyy等格式？

Answer 1

从 Java 8 开始，这变成了一行代码来获取LocalDate：

LocalDate.MIN.with(JulianFields.JULIAN_DAY, julianDay)
.format(DateTimeFormatter.ofPattern("MM/dd/yyyy"));

julianDay你的 7 位数字在哪里？

Answer 2

找到了一个有用的网站:http://www.rgagnon.com/javadetails/java-0506.html

这应该做的伎俩:

 public static int[] fromJulian(double injulian) {

      int jalpha,ja,jb,jc,jd,je,year,month,day;
      double julian = julian + HALFSECOND / 86400.0;
      ja = (int) julian;
      if (ja>= JGREG) {    

       jalpha = (int) (((ja - 1867216) - 0.25) / 36524.25);
       ja = ja + 1 + jalpha - jalpha / 4;
       }
     jb = ja + 1524;
   jc = (int) (6680.0 + ((jb - 2439870) - 122.1) / 365.25);
   jd = 365 * jc + jc / 4;
   je = (int) ((jb - jd) / 30.6001);
   day = jb - jd - (int) (30.6001 * je);
   month = je - 1;
   if (month > 12) month = month - 12;
   year = jc - 4715;
   if (month > 2) year--;
   if (year <= 0) year--;

   return new int[] {year, month, day};
  }