PHP计算执行时间

方法执行：

class index
{
    public function index(){
        //时间开始
        Timecount::start();


        //执行代码start

        //执行代码end

        //时间结束
        $time = Timecount::end();
        //输出时间
        Timecount::outputTime($time);
    }
}

时间类：Timecount.php

<?php

class Timecount
{

    private static $time_start;
    private static $time_end;

    /**
     * 开始时间
     */
    static function start()
    {
        self::$time_start = microtime(true);
    }

    /**
     * 结束计算
     * @return float
     */
    static function end()
    {
        self::$time_end = microtime(true);
        $time = self::$time_end - self::$time_start;
        return $time;
    }

    /**
     * 打印输出统计时间
     * @param $time
     */
    static function outputTime($time){
        $colorArr = ["red", "blue", "yellow"];
        $rand_key = mt_rand(0, count($colorArr) - 1);

        //对浮点数进行四舍五入
        $time = round($time, 3)."s";

        var_dump("<font color='" . $colorArr[$rand_key] . "'>时间（秒）：</font>" . $time);
        echo '<br />';
    }
}

输出：

统计微秒，两种方法：

1.

$time_start = microtime(true);

2. 

    /**
     * 统计 微妙
     */
    public static function microtime_float()
    {
        list($usec, $sec) = explode(" ", microtime());
        $ret = ((float)$usec + (float)$sec);
        return $ret;
    }