DateTime
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DateTime::__construct

date_create

(PHP 5 >= 5.2.0)

DateTime::__construct -- date_create — Returns new DateTime object

说明

面向对象风格

public DateTime::__construct() ([ string $time = "now" [, DateTimeZone $timezone = NULL ]] )

过程化风格

DateTime date_create ([ string $time = "now" [, DateTimeZone $timezone = NULL ]] )

Returns new DateTime object.

参数

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 desired time zone.

If $timezone is omitted, the current timezone will be used.

Note:

The $timezone parameter and the current timezone are ignored when the $time parameter either is a UNIX timestamp (e.g. @946684800) or specifies a timezone (e.g. 2010-01-28T15:00:00+02:00).

返回值

Returns a new DateTime instance. 过程化风格在失败时返回 FALSE。

错误/异常

Emits Exception in case of an error.

更新日志

版本 说明
5.3.0 If an invalid date is specified, then an exception is now thrown. Previously an error was emitted.

范例

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

参见

DateTime
在线手册：中文 英文
PHP手册
PHP手册 - N: Returns new DateTime object

用户评论:

sebi at timewaster dot de (24-Feb-2012 09:50)

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 (22-Dec-2011 03:17)

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 (24-May-2011 02:14)

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 (05-May-2010 11:50)

"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 (12-Jan-2010 04:37)

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 (12-Jan-2010 04:24)

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"

?>