我想把我的LocalDateTime字段保存为长,这样我就可以把它存储在我的SQLite数据库中。我如何才能做到这一点?
var datetime = LocalDateTime.now()
var longdt: Long = getString(datetime).toLong()
你可以使用 toEpochSecond()
和 ofEpochSecond()
转换成从 long
的值,精确到秒。
例子(在Java中
LocalDateTime now = LocalDateTime.now();
long nowInSeconds = now.toEpochSecond(ZoneOffset.UTC);
LocalDateTime dateTime = LocalDateTime.ofEpochSecond(nowInSeconds, 0, ZoneOffset.UTC);
System.out.println("now = " + now);
System.out.println("nowInSeconds = " + nowInSeconds);
System.out.println("dateTime = " + dateTime);
产量
now = 2020-05-12T12:12:36.984263200
nowInSeconds = 1589285556
dateTime = 2020-05-12T12:12:36
如果你需要 long
精确到毫秒的值,这样做。
LocalDateTime now = LocalDateTime.now();
long nowInMillis = now.toEpochSecond(ZoneOffset.UTC) * 1000
+ now.get(ChronoField.MILLI_OF_SECOND);
LocalDateTime dateTime = LocalDateTime.ofEpochSecond(nowInMillis / 1000,
(int) (nowInMillis % 1000 * 1000000), ZoneOffset.UTC);
System.out.println("now = " + now);
System.out.println("nowInMillis = " + nowInMillis);
System.out.println("dateTime = " + dateTime);
输出
now = 2020-05-12T12:16:38.881510700
nowInMillis = 1589285798881
dateTime = 2020-05-12T12:16:38.881
如果需要,请指定除 UTC
但在这种情况下,你应该真正地使用 ZonedDateTime
或 OffsetDateTime
而不是 LocalDateTime
.
如果你说的长是指秒数或毫秒数,请用这种方式。
LocalDateTime(以纪元为单位)秒
val seconds = datetime.atZone(ZoneOffset.UTC).toEpochSecond())
LocalDateTime改为epoch毫秒。
val milliseconds = datetime.atZone(ZoneOffset.UTC)?.toInstant()?.toEpochMilli()