使用DateTime / DateTimeZone调整PHP中的时区 [英] Adjusting time zone in PHP with DateTime / DateTimeZone

问题描述

在PHP中进行时区调整有很多信息，但是由于所有的噪音，我还没有找到一个具体的答案。

在一个时区有一段时间，我想把它转换成另一个时区的时间。

这个本质上是我想要做的，但是我只需要使用内置的PHP库即可，而不是PEAR Date。

是我一直在做的，但似乎总是给我相对于GMT的偏移：

  $ los_angeles_time_zone = new DateTimeZone （美国/洛杉矶）; 
 $ hawaii_time_zone = new DateTimeZone（'Pacific / Honolulu'）; 
 
 $ date_time_los_angeles = new DateTime（'2009-09-18 05:00:00'，$ los_angeles_time_zone）; 
 printf（LA时间：％s< br />，$ date_time_los_angeles->格式（DATE_ATOM））; 
 
 $ time_offset = $ hawaii_time_zone-> getOffset（$ date_time_los_angeles）; 
 printf（Offset：％s< br />，$ time_offset）; 
  

这是输出：

LA时间：2009-09-18T05：00：00-07：00

偏移量：-36000

我期待3小时（10800秒）。但是'-7：00'的东西告诉我，它保持一切都相对于格林尼治标准时间，这也许解释了为什么它给我绝对的偏移。

得到两个时区之间的偏移量，而不是所有的GMT hoohah？

谢谢。

更新： p>

我发现我可以做到这一点，得到我想要的东西：

  $ date_time_los_angeles = new DateTime（'2009-09-18 05:00:00'，$ los_angeles_time_zone）; 
 printf（LA Time：％s< br />，$ date_time_los_angeles->格式（DATE_ATOM））; 
 
 $ date_time_hawaii = new DateTime（'2009-09-18 05:00:00'，$ hawaii_time_zone）; 
 printf（夏威夷时间：％s< br />，$ date_time_hawaii->格式（DATE_ATOM））; 
 
 
 $ time_offset = $ los_angeles_time_zone-> getOffset（$ date_time_los_angeles） -  $ hawaii_time_zone-> getOffset（$ date_time_los_angeles）; 
 printf（Offset：％s< br />，$ time_offset）; 
  

但是对我来说感觉很尴尬。任何人都知道一个更干净的方法来做到这一点？

解决方案

这里有几个使用DateTime类的函数。第一个返回两个时区之间的秒差。第二个返回从一个时区到另一个时区的翻译。

  function timezone_diff（$ tz_from，$ tz_to，$ time_str ='now'）
 {
 $ dt = new DateTime（$ time_str，new DateTimeZone（$ tz_from））; 
 $ offset_from = $ dt-> getOffset（）; 
 $ timestamp = $ dt-> getTimestamp（）; 
 $ offset_to = $ dt-> setTimezone（new DateTimezone（$ tz_to）） - > setTimestamp（$ timestamp） - > getOffset（）; 
 return $ offset_to  -  $ offset_from; 
} 
 
 function time_translate（$ tz_from，$ tz_to，$ time_str ='now'，$ format ='Ymd H：i：s'）
 {
 $ dt = new DateTime（$ time_str，new DateTimezone（$ tz_from））; 
 $ timestamp = $ dt-> getTimestamp（）; 
 return $ dt-> setTimezone（new DateTimezone（$ tz_to）） - > setTimestamp（$ timestamp） - > format（$ format）; 
} 
  

演示：

  $ los_angeles_time ='2009-09-18 05:00:00'; 
 $ los_angeles_tz ='America / Los_Angeles'; 
 $ hawaii_tz ='太平洋/檀香山'; 
 
 $ los_angeles_hawaii_diff = timezone_diff（$ los_angeles_tz，$ hawaii_tz，$ los_angeles_time）; 
 echo $ los_angeles_hawaii_diff。 '< br />'; 
 
 $ hawaii_time = time_translate（$ los_angeles_tz，$ hawaii_tz，$ los_angeles_time）; 
 echo $ hawaii_time。 '< br />'; 
  

There's a lot of info on doing time zone adjustments in PHP, but I haven't found an answer for specifically what I want to do due to all the noise.

Given a time in one timezone, I want to convert it to the time in another timezone.

This is essentially what I want to do, but I need to be able to do it using only the built-in PHP libs, not PEAR Date.

This is what I've been doing, but it seems to always give me the offset relative to GMT:

$los_angeles_time_zone = new DateTimeZone('America/Los_Angeles');
$hawaii_time_zone = new DateTimeZone('Pacific/Honolulu');

$date_time_los_angeles = new DateTime('2009-09-18 05:00:00', $los_angeles_time_zone);
printf("LA Time: %s<br/>", $date_time_los_angeles->format(DATE_ATOM));

$time_offset = $hawaii_time_zone->getOffset($date_time_los_angeles);
printf("Offset: %s<br/>", $time_offset);

This is the output:

LA Time: 2009-09-18T05:00:00-07:00
Offset: -36000

I was expecting 3 hours (10800 seconds). but the '-7:00' thing tells me it's keeping everything relative to GMT, which maybe explains why it's giving me the "absolute" offset.

How do I just get the offset between the two timezones without all of this GMT hoohah?

Thanks.

UPDATE:

I occured to me that I could do this and get what I want:

    $date_time_los_angeles = new DateTime('2009-09-18 05:00:00', $los_angeles_time_zone);
printf("LA Time: %s<br/>", $date_time_los_angeles->format(DATE_ATOM));

$date_time_hawaii = new DateTime('2009-09-18 05:00:00', $hawaii_time_zone);
printf("Hawaii Time: %s<br/>", $date_time_hawaii->format(DATE_ATOM));


$time_offset = $los_angeles_time_zone->getOffset($date_time_los_angeles) - $hawaii_time_zone->getOffset($date_time_los_angeles);
printf("Offset: %s<br/>", $time_offset);

But it feels awkward to me. Anyone know a cleaner way to do it?

解决方案

Here are a couple of functions using the DateTime classes. The first one will return the difference in seconds between two timezones. The second returns a "translation" of the time from one timezone to another.

function timezone_diff($tz_from, $tz_to, $time_str = 'now')
{
    $dt = new DateTime($time_str, new DateTimeZone($tz_from));
    $offset_from = $dt->getOffset();
    $timestamp = $dt->getTimestamp();
    $offset_to = $dt->setTimezone(new DateTimezone($tz_to))->setTimestamp($timestamp)->getOffset();
    return $offset_to - $offset_from;
}

function time_translate($tz_from, $tz_to, $time_str = 'now', $format = 'Y-m-d H:i:s')
{
    $dt = new DateTime($time_str, new DateTimezone($tz_from));
    $timestamp = $dt->getTimestamp();
    return $dt->setTimezone(new DateTimezone($tz_to))->setTimestamp($timestamp)->format($format);
}

Demo:

$los_angeles_time = '2009-09-18 05:00:00';
$los_angeles_tz   = 'America/Los_Angeles';
$hawaii_tz        = 'Pacific/Honolulu';

$los_angeles_hawaii_diff = timezone_diff($los_angeles_tz, $hawaii_tz, $los_angeles_time);
echo $los_angeles_hawaii_diff . '<br />';

$hawaii_time = time_translate($los_angeles_tz, $hawaii_tz, $los_angeles_time);
echo $hawaii_time . '<br />';

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