把字符串时间转换为timestamp

$strtime = "2000-02-12 16:20:35";

$array = explode("-",$strtime);
$year = $array[0];
$month = $array[1];

$array = explode(":",$array[2]);
$minute = $array[1];
$second = $array[2];

$array = explode(" ",$array[0]);
$day = $array[0];
$hour = $array[1];

$timestamp = mktime($hour,$minute,$second,$month,$day,$year);

echo "字符串时间：$strtime
";
echo "年：$year
";
echo "月：$month
";
echo "日：$day
";
echo "时：$hour
";
echo "分：$minute
";
echo "秒：$second
";
echo "转换为timestamp：" . $timestamp . "
";
echo "从timestamp转换回来：" . date("y-m-d h:i:s",$timestamp) . "
";
?>