Java library for dealing with win32 FILETIME?
Are there any Java libraries around for dealing with the win32 FILETIME/ time intervals ? It's basically a 64 bit timestamp in 100ns intervals since January 1, 1601.
(For my particular needs, converting to/from java.util.Date or an appropriate joda time eq开发者_开发技巧uivalent would do, although I'll need access to at least microsecond resolution - which neither seems to provide.)
If you are fine with millisecond resolution, this would work:
/** Difference between Filetime epoch and Unix epoch (in ms). */
private static final long FILETIME_EPOCH_DIFF = 11644473600000L;
/** One millisecond expressed in units of 100s of nanoseconds. */
private static final long FILETIME_ONE_MILLISECOND = 10 * 1000;
public static long filetimeToMillis(final long filetime) {
return (filetime / FILETIME_ONE_MILLISECOND) - FILETIME_EPOCH_DIFF;
}
public static long millisToFiletime(final long millis) {
return (millis + FILETIME_EPOCH_DIFF) * FILETIME_ONE_MILLISECOND;
}
At this point, converting from ms to a Date object is quite straightforward.
Here's a Java 8+ java.time
based solution that keeps 100-nanosecond precision:
public static final Instant ZERO = Instant.parse("1601-01-01T00:00:00Z");
public static long fromInstant(Instant instant) {
Duration duration = Duration.between(ZERO, instant);
return duration.getSeconds() * 10_000_000 + duration.getNano() / 100;
}
public static Instant toInstant(long fileTime) {
Duration duration = Duration.of(fileTime / 10, ChronoUnit.MICROS).plus(fileTime % 10 * 100, ChronoUnit.NANOS);
return ZERO.plus(duration);
}
Last time I solved this using JNI... (Although not on Windows, this was unix)
That is, a piece of C++ code that called the native OS functions, and then called that code using Java Native Interface.
A bit clunky, but it was the only way I could find (Also needed the i-node).
EDIT: Assuming the values are already obtained from some other source, Date4J can handle seconds with 9 decimals, but it is not as feature rich as Joda.
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