(PHP 5 >= 5.2.0)
DateTime::__construct -- date_create — Returns new DateTime object
面向对象风格
过程化风格
Returns new DateTime object.
time
日期/时间字符串。正确格式的说明详见 日期与时间格式。
Enter NULL here to obtain the current time when using
the $timezone parameter.
timezone
A DateTimeZone object representing the
timezone of $time.
If $timezone is omitted,
the current timezone will be used.
Note:
The
$timezoneparameter and the current timezone are ignored when the$timeparameter either is a UNIX timestamp (e.g. @946684800) or specifies a timezone (e.g. 2010-01-28T15:00:00+02:00).
Returns a new DateTime instance.
过程化风格在失败时返回 FALSE。
Emits Exception in case of an error.
| 版本 | 说明 |
|---|---|
| 5.3.0 |
If time contains an invalid
date/time format, then an
exception is now thrown. Previously an error was emitted.
|
Example #1 DateTime::__construct() example
面向对象风格
<?php
try {
$date = new DateTime('2000-01-01');
} catch (Exception $e) {
echo $e->getMessage();
exit(1);
}
echo $date->format('Y-m-d');
?>
过程化风格
<?php
$date = date_create('2000-01-01');
if (!$date) {
$e = date_get_last_errors();
foreach ($e['errors'] as $error) {
echo "$error\n";
}
exit(1);
}
echo date_format($date, 'Y-m-d');
?>
以上例程会输出：
2000-01-01
Example #2 Intricacies of DateTime::__construct()
<?php
// Specified date/time in your computer's time zone.
$date = new DateTime('2000-01-01');
echo $date->format('Y-m-d H:i:sP') . "\n";
// Specified date/time in the specified time zone.
$date = new DateTime('2000-01-01', new DateTimeZone('Pacific/Nauru'));
echo $date->format('Y-m-d H:i:sP') . "\n";
// Current date/time in your computer's time zone.
$date = new DateTime();
echo $date->format('Y-m-d H:i:sP') . "\n";
// Current date/time in the specified time zone.
$date = new DateTime(null, new DateTimeZone('Pacific/Nauru'));
echo $date->format('Y-m-d H:i:sP') . "\n";
// Using a UNIX timestamp. Notice the result is in the UTC time zone.
$date = new DateTime('@946684800');
echo $date->format('Y-m-d H:i:sP') . "\n";
// Non-existent values roll over.
$date = new DateTime('2000-02-30');
echo $date->format('Y-m-d H:i:sP') . "\n";
?>
以上例程的输出类似于：
2000-01-01 00:00:00-05:00 2000-01-01 00:00:00+12:00 2010-04-24 10:24:16-04:00 2010-04-25 02:24:16+12:00 2000-01-01 00:00:00+00:00 2000-03-01 00:00:00-05:00
sebi at timewaster dot de (2012-02-24 13:50:39)
Note that although a milliseconds portion in ISO8601 timestamps is legal, PHP cannot parse them and will throw an exception. No parser in PHP can parse it.
cHao (2011-12-22 07:17:26)
There's a reason for ignoring the time zone when you pass a timestamp to __construct. That is, UNIX timestamps are by definition based on UTC. @1234567890 represents the same date/time regardless of time zone. So there's no need for a time zone at all.
joel dot kallman at gmail dot com (2011-05-23 18:14:09)
A definite "gotcha" (while documented) that exists in the __construct is that it ignores your timezone if the $time is a timestamp. While this may not make sense, the object does provide you with methods to work around it.
<?php
// New Timezone Object
$timezone = new DateTimeZone('America/New_York');
// New DateTime Object
$date = new DateTime('@1306123200', $timezone);
// You would expect the date to be 2011-05-23 00:00:00
// But it actually outputs 2011-05-23 04:00:00
echo $date->format('Y-m-d H:i:s');
// You can still set the timezone though like so...
$date->setTimezone($timezone);
// This will now output 2011-05-23 00:00:00
echo $date->format('Y-m-d H:i:s');
?>
Tim Strehle (2010-05-05 03:50:14)
"The $timezone parameter and the current timezone are ignored when the $time parameter […] is a UNIX timestamp."
Watch out – this means that these two are NOT equivalent, they result in different timezones (unless your current timezone is GMT):
<?php
$d = new DateTime(); $d->setTimestamp($t);
echo $o->format('O');
// +0200
$d = new DateTime('@' . $t);
echo $o->format('O');
// +0000
?>
kendsnyder at gmail dot com (2010-01-12 08:37:05)
Also forgot to mention, that MySQL "zeroed" dates do not throw an error but produce a non-sensical date:
<?php
$d = new DateTime("0000-00-00");
$d->format("Y-m-d"); // "-0001-11-30"
?>
Another good reason to write your own class that extends from DateTime.
kendsnyder at gmail dot com (2010-01-12 08:24:35)
The theoretical limits of the date range seem to be "-9999-01-01" through "9999-12-31" (PHP 5.2.9 on Windows Vista 64):
<?php
$d = new DateTime("9999-12-31");
$d->format("Y-m-d"); // "9999-12-31"
$d = new DateTime("0000-12-31");
$d->format("Y-m-d"); // "0000-12-31"
$d = new DateTime("-9999-12-31");
$d->format("Y-m-d"); // "-9999-12-31"
?>
Dates above 10000 and below -10000 do not throw errors but produce weird results:
<?php
$d = new DateTime("10019-01-01");
$d->format("Y-m-d"); // "2009-01-01"
$d = new DateTime("10009-01-01");
$d->format("Y-m-d"); // "2009-01-01"
$d = new DateTime("-10019-01-01");
$d->format("Y-m-d"); // "2009-01-01"
?>