java计算特定时区中两个ZoneDateTime对象之间的天数？

Question

我有下面的代码片段，其中有两个日期对象dates[0]和dates[1]。两者都转换为GMT+10时区。我试图在GMT+10时区，而不是UTC，找到这两个日期之间的天数（逻辑日历天数）

我试过ChronoUnit.DAYS.between()，比如下面，但我相信它会先将日期转换为UTC（我希望下面打印1和0，但它打印0和0）

Date[] dates = new Date[2];
SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
dates[1] = formatter.parse("2018-12-04T12:00:00");
dates[2] = formatter.parse("2018-12-04T16:00:00");
long toDate = 1543942800000L; \\2018-12-04T17:00:00
String timeZone = "GMT+10";
ZonedDateTime toDateZoned = ZonedDateTime.ofInstant(
    Instant.ofEpochMilli(toDate),
    ZoneId.of(timeZone)
);
for (Date ele: dates) {
    ZonedDateTime eleZoned = ZonedDateTime.ofInstant(
        ele.toInstant(),
        ZoneId.of(timeZone)
    );
    System.out.println(ChronoUnit.DAYS.between(eleZoned,toDateZoned));
}

如果我用

System.out.println(eleZoned);
System.out.println(toDateZoned);
System.out.println(ChronoUnit.DAYS.between(eleZoned, toDateZoned));

我得到以下输出

2018-12-04T22:00+10:00[GMT+10:00]
2018-12-05T03:00+10:00[GMT+10:00]
0
2018-12-05T02:00+10:00[GMT+10:00]
2018-12-05T03:00+10:00[GMT+10:00]
0

Answer 1

如果需要日期之间的日历日，可以在调用between()之前将其转换为LocalDate

Date[] dates = new Date[2];
TimeZone tz = TimeZone.getTimeZone("GMT+10");
SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
formatter.setTimeZone(tz);
dates[0] = formatter.parse("2018-12-05T12:00:00");
dates[1] = formatter.parse("2018-12-04T16:00:00");
long toDate = 1543942800000L; //2018-12-04T17:00:00
String timeZone = "GMT+10";
ZonedDateTime toDateZoned = ZonedDateTime.ofInstant(
    Instant.ofEpochMilli(toDate),
    ZoneId.of(timeZone));
for (Date ele: dates) {
  ZonedDateTime eleZoned = ZonedDateTime.ofInstant(
      ele.toInstant(),
      ZoneId.of(timeZone));
  System.out.println("Dates " + eleZoned + " " + toDateZoned);
  System.out.println(ChronoUnit.DAYS.between(eleZoned,toDateZoned));
  System.out.println(ChronoUnit.DAYS.between(eleZoned.toLocalDate(),toDateZoned.toLocalDate()));