在 java.time (Java 8) 中正确地将时间转换为毫秒
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Converting a time to milliseconds correctly in java.time (Java 8)
提问by Seagull
I've been trying to convert a "DateTime" to milliseconds using the java.time package built into Java 8.
我一直在尝试使用 Java 8 中内置的 java.time 包将“DateTime”转换为毫秒。
But I haven't been able to do it correctly. I am trying to convert "29/Jan/2015:18:00:00" to milliseconds. The following is something I tried
但我一直无法正确地做到这一点。我正在尝试将“29/Jan/2015:18:00:00”转换为毫秒。以下是我尝试过的
Instant instant = Instant.parse("2015-01-29T18:00:00.0z");
Long instantMilliSeconds = Long.parseLong(instant.getEpochSecond() + "" + instant.get(ChronoField.MILLI_OF_SECOND));
System.out.println(new Date(instantMilliSeconds)); // prints Sun Jun 14 05:06:00 PDT 1970
I tried using LocalDateTime, but couldn't find a way to effectively do the conversion to milliseconds. I am not saying this is the best way to do this, if you know something better, I would really appreciate some pointers.
我尝试使用LocalDateTime，但找不到有效地将转换为毫秒的方法。我并不是说这是最好的方法，如果你知道更好的东西，我真的很感激一些指示。
采纳答案by Jeffrey
You should use Instant::toEpochMilli.
你应该使用Instant::toEpochMilli.
System.out.println(instant.toEpochMilli());
System.out.println(instant.getEpochSecond());
System.out.println(instant.get(ChronoField.MILLI_OF_SECOND));
prints
印刷
1422554400000
1422554400
0
Your version did not work because you forgot to pad instant.get(ChronoField.MILLI_OF_SECOND)with extra zeros to fill it out to 3 places.
您的版本不起作用，因为您忘记instant.get(ChronoField.MILLI_OF_SECOND)用额外的零填充以将其填充到 3 个位置。
回答by MadProgrammer
From Date and Time Classesthe tutorials...
从日期和时间类教程...
DateTimeFormatter formatter
= DateTimeFormatter.ofPattern("dd/MMM/yyyy:HH:mm:ss");
LocalDateTime date = LocalDateTime.parse("29/Jan/2015:18:00:00", formatter);
System.out.printf("%s%n", date);
Prints 2015-01-29T18:00
印刷 2015-01-29T18:00
ZoneId id = ZoneId.systemDefault();
ZonedDateTime zdt = ZonedDateTime.of(date, id);
System.out.println(zdt.toInstant().toEpochMilli());
Prints 1422514800000
印刷 1422514800000
回答by Seagull
Okay, I think I finally found an easy way to do what I am trying to do
好的，我想我终于找到了一种简单的方法来做我想做的事情
LocalDateTime localDateTime = LocalDateTime.parse(date, DateTimeFormatter.ofPattern("dd/MMM/uuuu:H:m:s"));
System.out.println(localDateTime.toInstant(ZoneOffset.UTC).toEpochMilli());
Prints 1390903200000
打印 1390903200000
