php 时间转时间戳

<?php
// 获取当前时间戳
$timestamp = time();
echo "当前时间戳: " . $timestamp . "\n";

// 将时间戳转换为日期时间
$date = date('Y-m-d H:i:s', $timestamp);
echo "转换后的日期时间: " . $date . "\n";

// 将日期时间转换为时间戳
$date_string = '2023-04-01 12:00:00';
$timestamp_from_string = strtotime($date_string);
echo "日期时间转换为时间戳: " . $timestamp_from_string . "\n";
?>

<?php
$date_string = '2023-04-01 12:00:00';
$date_object = new DateTime($date_string);
$timestamp = $date_object->getTimestamp();
echo "日期时间转换为时间戳: " . $timestamp . "\n";
?>

<?php
date_default_timezone_set('UTC');
$date_string = '2023-04-01 12:00:00';
$timestamp = strtotime($date_string);
echo "UTC时间戳: " . $timestamp . "\n";

$date_object = new DateTime($date_string, new DateTimeZone('Asia/Shanghai'));
echo "上海时区时间: " . $date_object->format('Y-m-d H:i:s') . "\n";
?>