php unix timestamp to date

$date = new DateTime();
echo $date->getTimestamp();

<?php
$timestamp=1333699439;
echo gmdate("Y-m-d\TH:i:s\Z", $timestamp);
?>

$currentTime = DateTime::createFromFormat( 'U', $timestamp );

<?php
$date = new DateTime();
echo $date->format('U = Y-m-d H:i:s') . "\n";

$date->setTimestamp(1171502725);
echo $date->format('U = Y-m-d H:i:s') . "\n";
?>