function microtimeFloat() {
list($usec,$sec) = explode(" ",microtime());
return((float)$usec + (float)$sec);
}
1.测试file_put_contents
$userCount = 1000;
$itemCount = 1000;
$file = 'ratings.txt';
file_exists($file) &&unlink($file);
$timeStart = microtimeFloat();
for ($i = 0; $i < $userCount; $i++) {
$uid =random(32);
for ($j = 0;$j < $itemCount; $j++) {
$itemId = mt_rand(1,300000);
$rating = $j == 0 ? 1 : mt_rand(1,100) / 100;
$line = sprintf("%s,%d,%s\n",$uid,$itemId,$rating);
file_put_contents($file,$line,FILE_APPEND);
}
}
$timeEnd = microtimeFloat();
echo sprintf("Spend time: |%s| second(s)\n",$timeEnd -$timeStart);
?>
测试结果:
测试过程中出现了打开文件的错误，而且程序执行完成以后写入的数据不完整，只有999997行，漏了3行。最重要的一点是时间花了307秒多，而用fwrite只花了10秒多的时间，差距还是不小的。
D:\myPHP\research>PHP test2.PHP
PHP Warning: file_put_contents(ratings.txt): Failed to open stream:Permission
denied in D:\myPHP\research\test2.PHP on line 79
Warning: file_put_contents(ratings.txt): Failed to open stream:Permission denie
d in D:\myPHP\research\test2.PHP on line 79
Spend time: |307.0586669445|second(s)
...
999994:98xDtLjaeD8MG9ywifegZvRRQzVBZbbw,167670,0.15
999995:98xDtLjaeD8MG9ywifegZvRRQzVBZbbw,234223,0.13
999996:98xDtLjaeD8MG9ywifegZvRRQzVBZbbw,84947,0.79
999997:98xDtLjaeD8MG9ywifegZvRRQzVBZbbw,6489,0.38
2.测试fwrite
$userCount = 1000;
$itemCount = 1000;
$file = 'ratings.txt';
file_exists($file) &&unlink($file);
$fp = @fopen($file,'ab');
if (!$fp) die("Open $file Failed");
$timeStart = microtimeFloat();
for ($i = 0; $i < $userCount; $i++) {
$uid =random(32);
for ($j = 0;$j < $itemCount; $j++) {
$itemId = mt_rand(1,$rating);
fwrite($fp,$line);
$k++;
}
}
if ($fp) @fclose($fp);
$timeEnd = microtimeFloat();
echo sprintf("Spend time: |%s| second(s)\n",$timeEnd -$timeStart);
?>
测试结果:
写一百万行记录，10秒左右写完，对于PHP来说，速度算不错了。这是在我的个人电脑上面测试的，如果在生产机上测试，可能速度还要快一些。
D:\myPHP\research>PHP test2.PHP
Spend time: |10.764221191406|second(s)
用fwrite写入的数据是完整的
999997,QOvcZYFJFlFHjiGyGxAc615kOXdX3Yii,246982,0.03
999998,240160,0.39
999999,46296,0.61
1000000,26211,0.14
3.总结
如果要往文件里面写入大量的数据，则推荐用fwrite，不要用file_put_contents。在高并发的请求中也建议用fwrite。
