PHPでタイムゾーンを操作する方法は？

正确使用PHP的DateTime和DateTimeZone类处理时区，建议存储UTC时间并在显示时转换为用户时区，确保跨区域一致性。

Working with timezones in PHP is essential for handling date and time accurately across different regions. The key is using PHP's DateTime and DateTimeZone classes properly to avoid confusion and errors.

Set and Use Timezones with DateTime

PHP's DateTime class allows you to create date/time objects with specific timezones. Always specify a timezone instead of relying on the server's default.

Example:

$timezone = new DateTimeZone('America/New_York');
$date = new DateTime('2024-04-05 10:00:00', $timezone);
echo $date->format('Y-m-d H:i:s T'); // Output: 2024-04-05 10:00:00 EDT

If no timezone is provided, PHP may use the system default, which can lead to inconsistencies.

Convert Between Timezones

You can convert a DateTime object from one timezone to another using the setTimezone() method.

$date = new DateTime('2024-04-05 10:00:00', new DateTimeZone('America/New_York'));
$date->setTimezone(new DateTimeZone('Europe/London'));
echo $date->format('Y-m-d H:i:s T'); // Output: 2024-04-05 15:00:00 BST

This is useful when displaying times to users in their local timezone.

Store Times in UTC, Display in Local Time

Best practice: store all timestamps in UTC in your database. Then convert to the user's timezone when displaying.

• Create UTC times: new DateTime('now', new DateTimeZone('UTC'))
• Save in format: $date->format('Y-m-d H:i:s')
• On output, convert to user’s timezone using setTimezone()

This avoids issues with daylight saving time and server location changes.

Get and Validate Timezone Names

Use valid timezone identifiers from the PHP supported timezones list. Invalid names cause exceptions.

To check if a timezone is valid:

if (in_array('America/Chicago', DateTimeZone::listIdentifiers())) {
    // It's a valid timezone
}

You can also list all available timezones using DateTimeZone::listIdentifiers().

Basically, always use DateTime and DateTimeZone, work in UTC internally, and convert only for display. That keeps your app reliable across regions.

以上がPHPでタイムゾーンを操作する方法は？の詳細内容です。詳細については、PHP 中国語 Web サイトの他の関連記事を参照してください。