php实例代码：时间友好格式化

<?php

class DateFormat
{
private static $_DIFF_FORMAT = array(
'DAY' => '%s天前',
'DAY_HOUR' => '%s天%s小时前',
'HOUR' => '%s小时',
'HOUR_MINUTE' => '%s小时%s分前',
'MINUTE' => '%s分钟前',
'MINUTE_SECOND' => '%s分钟%s秒前',
'SECOND' => '%s分钟前',
);

/**
* 友好格式化时间
*
* @param int 时间
* @param array $formats
* @return string
*/
public static function diff($timestamp, $formats = null)
{
if ($formats == null) {
$formats = self::$_DIFF_FORMAT;
}
/* 计算出时间差 */
$seconds = time() - $timestamp;
$minutes = floor($seconds / 60);
$hours = floor($minutes / 60);
$days = floor($hours / 24);

if ($days > 0) {
$diffFormat = 'DAY';
} else {
$diffFormat = ($hours > 0) ? 'HOUR' : 'MINUTE';
if ($diffFormat == 'HOUR') {
$diffFormat .= ($minutes > 0 && ($minutes - $hours * 60) > 0) ? '_MINUTE' : '';
} else {
$diffFormat = (($seconds - $minutes * 60) > 0 && $minutes > 0)
? $diffFormat.'_SECOND' : 'SECOND';
}
}

$dateDiff = null;
switch ($diffFormat) {
case 'DAY':
$dateDiff = sprintf($formats[$diffFormat], $days);
break;
case 'DAY_HOUR':
$dateDiff = sprintf($formats[$diffFormat], $days, $hours - $days * 60);
break;
case 'HOUR':
$dateDiff = sprintf($formats[$diffFormat], $hours);
break;
case 'HOUR_MINUTE':
$dateDiff = sprintf($formats[$diffFormat], $hours, $minutes - $hours * 60);
break;
case 'MINUTE':
$dateDiff = sprintf($formats[$diffFormat], $minutes);
break;
case 'MINUTE_SECOND':
$dateDiff = sprintf($formats[$diffFormat], $minutes, $seconds - $minutes * 60);
break;
case 'SECOND':
$dateDiff = sprintf($formats[$diffFormat], $seconds);
break;
}
return $dateDiff;
}
}

echo DateFormat::diff('1310455823');
/* 33分钟47秒前 */