PHP实现获取毫秒时间戳的方法【使用microtime()函数】

function getMillisecond() {
  list($s1, $s2) = explode(' ', microtime());
  return (float)sprintf('%.0f', (floatval($s1) + floatval($s2)) * 1000);
}
/*
* 获取时间差，毫秒级
*/
function get_subtraction()
{
  $t1 = microtime(true);
  $t2 = microtime(true);
  return (($t2-$t1)*1000).'ms';
}
/*
* microsecond 微秒   millisecond 毫秒
*返回时间戳的毫秒数部分
*/
function get_millisecond()
{
  list($usec, $sec) = explode(" ", microtime());
  $msec=round($usec*1000);
  return $msec;
}
/*
*
*返回字符串的毫秒数时间戳
*/
function get_total_millisecond()
{
  $time = explode (" ", microtime () );
  $time = $time [1] . ($time [0] * 1000);
  $time2 = explode ( ".", $time );
  $time = $time2 [0];
  return $time;
}
/*
*
*返回当前 Unix 时间戳和微秒数(用秒的小数表示)浮点数表示，常用来计算代码段执行时间
*/
function microtime_float()
{
  list($usec, $sec) = explode(" ", microtime());
  return ((float)$usec + (float)$sec);
}
$millisecond = get_millisecond();
$millisecond = str_pad($millisecond,3,'0',STR_PAD_RIGHT);
echo date("YmdHis").$millisecond;