php实现的Timer页面运行时间监测类

<?php 
/** Timer class, 计算页面运行时间,可按不同key计算不同的运行时间 
*  Date:  2014-02-28 
*  Author: fdipzone 
*  Ver:  1.0 
* 
*  Func: 
*  public start    记录开始时间 
*  public end     记录结束时间 
*  public getTime   计算运行时间 
*  pulbic printTime  输出运行时间 
*  private getKey    获取key 
*  private getMicrotime 获取microtime 
*/ 
 
class Timer{ // class start 
 
  private $_start = array(); 
  private $_end = array(); 
  private $_default_key = 'Timer'; 
  private $_prefix = 'Timer_'; 
 
  /** 记录开始时间 
  * @param String $key 标记 
  */ 
  public function start($key=''){ 
    $flag = $this->getKey($key); 
    $this->_start[$flag] = $this->getMicrotime(); 
  } 
 
  /** 记录结束时间 
  * @param String $key 标记 
  */ 
  public function end($key=''){ 
    $flag = $this->getKey($key); 
    $this->_end[$flag] = $this->getMicrotime(); 
  } 
 
  /** 计算运行时间 
  * @param String $key 标记 
  * @return float 
  */ 
  public function getTime($key=''){ 
    $flag = $this->getKey($key); 
    if(isset($this->_end[$flag]) && isset($this->_start[$flag])){ 
      return (float)($this->_end[$flag] - $this->_start[$flag]); 
    }else{ 
      return 0; 
    } 
  } 
 
  /** 输出页面运行时间 
  * @param String $key 标记 
  * @return String 
  */ 
  public function printTime($key=''){ 
    printf("%srun time %f ms\r\n", $key==''? $key : $key.' ', $this->getTime($key)*1000); 
  } 
 
  /** 获取key 
  * @param String $key 标记 
  * @return String 
  */ 
  private function getKey($key=''){ 
    if($key==''){ 
      return $this->_default_key; 
    }else{ 
      return $this->_prefix.$key; 
    } 
  } 
 
  /** 获取microtime 
  */ 
  private function getMicrotime(){ 
    list($usec, $sec) = explode(' ', microtime()); 
    return (float)$usec + (float)$sec; 
  } 
} // class end 
?>

<?php 
 
require 'Timer.class.php'; 
 
$timer = new Timer(); 
$timer->start(); 
 
$timer->start('program1'); 
usleep(mt_rand(100000,500000)); 
$timer->end('program1'); 
$timer->printTime('program1'); 
 
$timer->start('program2'); 
usleep(mt_rand(100000,500000)); 
$timer->end('program2'); 
$timer->printTime('program2'); 
 
$timer->end(); 
$timer->printTime(); 
 
?>

program1 run time 163.285971 ms 
program2 run time 100.347042 ms 
run time 264.035940 ms