计算 linux 纪元时间属于 Java 的哪一天

Question

我正在尝试找出给定的 Linux Epoch TS 属于哪一天。

为了帮助解释更多，我给出了以下示例：

我曾尝试使用 JODATIME 解决此问题，但无法获得可行的解决方案。

// some code here that I need.... <---??

// The time set here below is (Tue 2019-09-10 14:05:00 UTC)
final long timestamp = 1568124300000L


if (timestamp = xxxxx) {
    System.out.println("The day it belongs to is: " + dayEpoch);
}

理想情况下，我希望打印的输出是：

The day it belongs to is: 2019-09-10

如果您提供实现此目的的代码示例，我们将不胜感激:)

Answer 1

您可以使用 java.time 来满足您的要求：

第一个选项（首选）：OffsetDateTime

final long timestamp = 1568124300000L;

// create an Instant from the timestamp
Instant instant = Instant.ofEpochMilli(timestamp);
// create a datetime object from the Instant
OffsetDateTime offsetDateTime = OffsetDateTime.ofInstant(instant, ZoneId.of("UTC"));
// print it in your desired formatting
System.out.println("The day it belongs to is: "
                    + offsetDateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd")));

第二个选项（有效，但不太合适）：ZonedDateTime

final long timestamp = 1568124300000L;

// create an Instant from the timestamp
Instant instant = Instant.ofEpochMilli(timestamp);
// create a datetime object from the Instant
ZonedDateTime zonedDateTime = ZonedDateTime.ofInstant(instant, ZoneId.of("UTC"));
// print it in your desired formatting
System.out.println("The day it belongs to is: "
                    + zonedDateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd")));

Please note that you can have different ZoneIds. You have clearly written that it is UTC in your case, so I took that one for the example. There is ZoneId.systemDefault(); to get a local timezone, the output for that is the same (date) on my system.
For using this, you will have to be using Java 8 or the ThreeTen-Backport…

计算 linux 纪元时间属于 Java 的哪一天

Working out which day a linux epoch time belongs in Java

java

datetime

epoch