如何在JAVA中将十进制值转换为24小时制时间格式

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英文:

How to convert decimal value to 24 hour time format in JAVA

问题

我从SQLServer中检索时间值,这些值显示为0.0833333333333333,而原始格式是24小时制的02:00。现在,我需要将这个小数值0.0833333333333333转换为02:00,以进行进一步的编码。在JAVA中是否有任何直接/简单的方法可以做到这一点?

英文:

I am retrieving time values from SQLServer which are displayed as 0.0833333333333333, while it originally is 02:00 in 24 hour format. Now, I need to convert this decimal value 0.0833333333333333 to 02:00 to do further coding. Is there any direct/simple way to do it in JAVA?

答案1

得分: 1

以下是翻译好的部分:

这是一个示例,使用12小时制,带有AM/PM,但使用java.time类:

// 没有偏移,没有时区:
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

...

double d = 0.7826388888888889;
long nanos = Math.round(d * 24L * 60L * 60L * 1_000_000_000L);
LocalTime localTime = LocalTime.ofNanoOfDay(nanos);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("h:mm a");
System.out.println(localTime.format(formatter));

这个示例会打印出以下结果:

6:47 PM

如果您喜欢,可以使用"h:mma"来获取6:47PM - 没有空格。

LocalTime保存了一个没有任何时区信息的时间值。

您可以在这里查看可用的格式选项列表:这里

更新

正如Ole V.V.指出的那样,您可以通过简化乘法来使代码更清晰。使用java.time.Durationjava.util.concurrent.TimeUnit

long nanosInOneDay = java.time.Duration.ofDays(1).toNanos();

或者

long nanosInOneDay = java.util.concurrent.TimeUnit.DAYS.toNanos(1);
英文:

Here is an example, using a 12 hour format, with AM/PM, but using java.time classes:

// no offset, no time zone:
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

...

double d = 0.7826388888888889;
long nanos = Math.round(d * 24L * 60L * 60L * 1_000_000_000L);
LocalTime localTime = LocalTime.ofNanoOfDay(nanos);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("h:mm a");
System.out.println(localTime.format(formatter));

This example prints the following:

6:47 PM

If you prefer, you can use "h:mma" to get 6:47PM - with no space.

LocalTime holds a time value without any time zone information.

You can see a list of the available formatting options here.

Update

As Ole V.V. points out, you can make the code clearer by simplifying the multiplication. Use java.time.Duration or java.util.concurrent.TimeUnit:

long nanosInOneDay = java.time.Duration.ofDays(1).toNanos();

or

long nanosInOneDay = java.util.concurrent.TimeUnit.DAYS.toNanos(1);

答案2

得分: 0

以下是一个示例:

double d = 0.0833333333333333;
Date date = new Date(Math.round(d * 24L * 60L * 60L * 1000L));
SimpleDateFormat format = new SimpleDateFormat("HH:mm");
format.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(format.format(date));
英文:

Here is an example:

double d = 0.0833333333333333;
Date date = new Date(Math.round(d * 24L * 60L * 60L * 1000L));
SimpleDateFormat format = new SimpleDateFormat("HH:mm");
format.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(format.format(date));

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  • 本文由 发表于 2020年8月6日 05:35:56
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