PHP DateTime 对象和 Date 函数的 Demo

<?php

//设置时间时区
date_default_timezone_set('PRC');
$dateFormat = "Y-m-d";
$dateTimeFormat = "Y-m-d H:i:s";

//获取当前时间
$date = new DateTime();
echo $date->format($dateTimeFormat) . "\n";

//时间2015-01-01加上7年5月4天4小时3分钟2秒
$date = new DateTime('2015-01-01');
$addDate = new DateInterval('P7Y5M4DT4H3M2S');
$date->add($addDate);
echo $date->format($dateTimeFormat) . "\n";

//时间2015-05-29加上1年2月3天
$date = new DateTime('2015');
$date->add(new DateInterval('P1Y2M3D'));
echo $date->format($dateFormat) . "\n";

//当前时间加上3小时2分钟1秒
$date = new DateTime();
$date->add(new DateInterval('PT3H2M1S'));
echo $date->format($dateTimeFormat) . "\n";

$date = DateTime::createFromFormat($dateFormat, '2009-02-15');
echo $date->format($dateTimeFormat) . "\n";

$date = new DateTime();
$date->setDate(2222, 12, 22);
echo $date->format($dateFormat) . "\n";

$date = new DateTime();
$date->setTime(14, 55);
echo $date->format($dateTimeFormat) . "\n";

$date = new DateTime();
$date->setTimestamp(1171502725);
echo $date->format($dateTimeFormat) . "\n";

//时间的比较

$Today = new DateTime();
$Tomorrow = new DateTime();
$Tomorrow->add(new DateInterval('P1D'));
$diff = $Tomorrow->diff($Today);
echo 'Difference: ' . $diff->format('%m month, %d days (total: %a days)') . "\n";

if ($Today < $Tomorrow) {
    echo "Today is before Tomorrow!\n";
}

//获取时间戳以及输出格式化的时间戳
$date = new DateTime();
echo $date->getTimestamp() . "\n";
echo $date->format($dateTimeFormat) . "\n";

<?php

//默认时区
date_default_timezone_set('PRC');

echo "今天:" . date("Y-m-d", time()) . "<br>";
echo "今天:" . date("Y-m-d", strtotime("18 june 2008")) . "<br>";
echo "昨天:" . date("Y-m-d", strtotime("-1 day")) . "<br>";
echo "明天:" . date("Y-m-d", strtotime("+1 day")) . "<br>";
echo "一周后:" . date("Y-m-d", strtotime("+1 week")) . "<br>";
echo "一周零两天四小时两秒后:" . date("Y-m-d G:H:s", strtotime("+1 week 2 days 4 hours 2 seconds")) . "<br>";
echo "下个星期四:" . date("Y-m-d", strtotime("next Thursday")) . "<br>";
echo "上个周一:" . date("Y-m-d", strtotime("last Monday")) . "<br>";
echo "一个月前:" . date("Y-m-d", strtotime("last month")) . "<br>";
echo "一个月后:" . date("Y-m-d", strtotime("+1 month")) . "<br>";
echo "十年后:" . date("Y-m-d", strtotime("+10 year")) . "<br>";