PHP中的const vs static

Question

在PHP5中,我可以向类声明一个const值:

class config
{
     const mailserver = 'mx.google.com';
}

但我也可以宣布公开静态:

class config
{
     public static $mailserver = 'mx.google.com';
}

如果是配置文件,我将在以后使用,例如:

imap_connect(config::$mailserver ...
imap_connect(config::mailserver ...

您认为哪个选项更适合使用？(更快,更少的内存负载等..)

谢谢.

Answer 1

静态变量可以改变,const不能改变.应该主要考虑配置变量是否应该能够在运行时更改,而不是更快.两者之间的速度差异(如果有的话)非常小,不值得考虑.

Answer 2

使用函数返回全局

0.0096,0.0053,0.0056,0.0054,0.0072,0.0063,0.006,0.0054,0.0054,0.0055,0.005,0.057,0,053,0.0049,0.064,0.0054,0.0053,0.0053,0.0061,0.0059,0.0076,config1

使用get instance normal class

0.0101,0.0089,0.0105,0.0088,0.0107,0.0083,0.0094,0.0081,0.0106,0.0093,0.0098,0.0092,0.009,0.0087,0.0087,0.0093,0.0095,0.0101,0.0086,0.0088,0.0082,config2

使用静态变量

0.0029,0.003,0.003,0.0029,0.0029,0.0029,0.003,0.0029,0.003,0.0031,0.0032,0.0031,0,029,0.0029,0.0029,0.0029,0.0031,0.0029,0.0029,0.0029,0.0029,config3

使用const var 0.0033,0.0031,0.0031,0.0031,0.0031,0.0031,0.0032,0.0031,0.0031,0.0031,0.0031,0.0034,0.0031,0.0031,0.0033,0.0031,0.0037,0.0031,0.0031,0.0032,0.0031,config4

function getTime() { 
    $timer = explode( ' ', microtime() ); 
    $timer = $timer[1] + $timer[0]; 
    return $timer; 
}

$config["time"] = "time";

class testconfig2
{
    public  $time = "time";
    static $instance;
    static function getInstance()
    {
        if(!isset(self::$instance))
            self::$instance = new testconfig2();
        return self::$instance;
    }
}

class testconfig3
{
    static $time = "time";
}

class testconfig4
{
    const time = "time";
}

function getConfig1()
{
    global $config;
    return $config;
}

$burncount = 2000;
$bcount = 22;

for($lcnt =1;$lcnt < $bcount;$lcnt++){
$start = getTime(); 
for($i=1;$i< $burncount;$i++)
{
    $gs=getConfig1();
    $t = $gs["time"];
} 
$end = getTime(); 
echo  round($end - $start,4).', ';
}
echo  ' config1<br/>';



for($lcnt =1;$lcnt < $bcount;$lcnt++){
$start = getTime(); 
for($i=1;$i< $burncount;$i++)
{
    $gs=testconfig2::getInstance();
    $t = $gs->time;
} 
$end = getTime(); 
echo  round($end - $start,4).', ';
}
echo  ' config2<br/>';



for($lcnt =1;$lcnt < $bcount;$lcnt++){
$start = getTime(); 
for($i=1;$i< $burncount;$i++)
{
    $gs=testconfig3::$time;
    $t = $gs;
} 
$end = getTime(); 
echo  round($end - $start,4).', ';
}
echo  ' config3<br/>';



for($lcnt =1;$lcnt < $bcount;$lcnt++){
$start = getTime(); 
for($i=1;$i< $burncount;$i++)
{
    $gs=testconfig4::time;
    $t = $gs;
} 
$end = getTime(); 
echo  round($end - $start,4).', ';
}
echo  ' config4<br/>';
?>