PHP的date函数可以完成这项工作。

日期()

描述:

string date(string $format [, int $timestamp = time()])

返回根据给定格式字符串使用给定整数时间戳格式化的字符串，如果没有给出时间戳则返回当前时间。

例子:

$today = date("F j, Y, g:i a");               // March 10, 2001, 5:16 pm
$today = date("m.d.y");                       // 03.10.01
$today = date("j, n, Y");                     // 10, 3, 2001
$today = date("Ymd");                         // 20010310
$today = date('h-i-s, j-m-y, it is w Day');   // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date('\i\t \i\s \t\h\e jS \d\a\y.'); // it is the 10th day.
$today = date("D M j G:i:s T Y");             // Sat Mar 10 17:16:18 MST 2001
$today = date('H:m:s \m \i\s\ \m\o\n\t\h');   // 17:03:18 m is month
$today = date("H:i:s");                       // 17:16:18
$today = date("Y-m-d H:i:s");                 // 2001-03-10 17:16:18 (the MySQL DATETIME format)

参考:这里有一个链接

由于使用夏令时，这比简单地在时间戳中添加或减去一天或一个月中的秒数更可靠。

PHP代码

// Assuming today is March 10th, 2001, 5:16:18 pm, and that we are in the
// Mountain Standard Time (MST) Time Zone

$today = date("F j, Y, g:i a");                 // March 10, 2001, 5:16 pm
$today = date("m.d.y");                         // 03.10.01
$today = date("j, n, Y");                       // 10, 3, 2001
$today = date("Ymd");                           // 20010310
$today = date('h-i-s, j-m-y, it is w Day');     // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date('\i\t \i\s \t\h\e jS \d\a\y.');   // it is the 10th day.
$today = date("D M j G:i:s T Y");               // Sat Mar 10 17:16:18 MST 2001
$today = date('H:m:s \m \i\s\ \m\o\n\t\h');     // 17:03:18 m is month
$today = date("H:i:s");                         // 17:16:18
$today = date("Y-m-d H:i:s");                   // 2001-03-10 17:16:18 (the MySQL DATETIME format)

我发现在PHP中获取当前时间的最简单方法是这样的。

//Prints out something like 10:00am Just be sure to set your timezone correctly.
date_default_timezone_set("America/Chicago");
$TIME = date('G:ia'); 

// Simply:
$date = date('Y-m-d H:i:s');

// Or:
$date = date('Y/m/d H:i:s');

// This would return the date in the following formats respectively:
$date = '2012-03-06 17:33:07';
// Or
$date = '2012/03/06 17:33:07';

/** 
 * This time is based on the default server time zone.
 * If you want the date in a different time zone,
 * say if you come from Nairobi, Kenya like I do, you can set
 * the time zone to Nairobi as shown below.
 */

date_default_timezone_set('Africa/Nairobi');

// Then call the date functions
$date = date('Y-m-d H:i:s');
// Or
$date = date('Y/m/d H:i:s');

// date_default_timezone_set() function is however
// supported by PHP version 5.1.0 or above.

有关时区参考，请参见支持的时区列表。

下面是一些常用的表示时间的字符:

H -以前导零表示的12小时格式(01到12) i -前导0的分钟(00到59) s -前导0的秒(00到59) a -小写的子午线前后(am或pm)

确定你的时区

<?php
    date_default_timezone_set("America/New_York");
    echo "The time is " . date("h:i:sa");
?>

看看这个(可选)

<?php
    $d = mktime(11, 14, 54, 8, 12, 2014);
    echo "Created date is " . date("Y-m-d h:i:sa", $d);
?>

为日期

<?php
    echo "Today is " . date("Y/m/d") . ;
    echo "Today is " . date("Y.m.d") . ;
    echo "Today is " . date("Y-m-d") . ;
    echo "Today is " . date("l");
?>

下面是一些常用来表示日期的字符:

d -表示一个月中的第一天(01 ~ 31) m -代表一个月(01 ~ 12) Y -年份(四位数) l(小写“l”)-代表星期几

Source-W3-Schools

 $date = new DateTime('now', new DateTimeZone('Asia/Kolkata'));
 echo $date->format('d-m-Y H:i:s');

更新

 //Also get am/pm in datetime:
 echo $date->format('d-m-Y H:i:s a'); // output 30-12-2013 10:16:15 am

对于日期格式，PHP date() Function很有用。