php 生成唯一订单号，文件锁

从网上找到一篇生成订单号的文章，但并发测试后发现会有重复的订单号生成，所以尝试加入文件锁，阻塞请求，来生成唯一订单号。

自己经过ab工具并发1000个请求，不会生成重复的订单号。

<?php/* * 生成的格式是: 20130103000001 前面几位为当前的日期,后面6位为系统自增长类型的编号 * 原理: * 1.获取当前日期格式化值; * 2.读取文件,上次编号的值+1最为当前此次编号的值(记录以文件的形式存储) * (下月会接着这个编号)*/class FileEveryDaySerialNumber{private $filename; //文件名private $separate; //系统分隔符private $width; //自动增长部分的个数public function __construct($width, $filename, $separate){$this->width = $width;$this->filename = $filename;$this->separate = $separate;}public function getOrUpdateNumber($current, $start){$record = IOUtil::read_content($this->filename);$arr = explode($this->separate, $record['content']);if($current == $arr[0]){//如果是同一天,则继续增长$arr[1]++;IOUtil::write_content($record['handle'],"$arr[0],$arr[1]", $this->filename); //将新值存入文件中return "$arr[0]".str_pad($arr[1],$this->width,0,STR_PAD_LEFT);}else{//如果两个日期不一样则重新从起始值开始$arr[0] = $current;$arr[1] = $start;IOUtil::write_content($record['handle'],"$arr[0],$arr[1]", $this->filename); //将新值存入文件中return "$arr[0]".str_pad($arr[1],$this->width,0,STR_PAD_LEFT);}}}class IOUtil{public static function read_content($filename){$bool = file_exists($filename);if(!$bool){touch($filename);}$handle = fopen($filename,"r+");flock($handle, LOCK_EX);// 进行排它型锁定if(filesize($filename) > 0){$readSize = filesize($filename);}else{$readSize = 20;}$content = fread($handle,$readSize);$arr = array('handle' => $handle,'content' => $content,);return $arr;}public static function write_content($handle,$content, $filename){fseek($handle,0);fwrite($handle, $content);fclose($handle);return $content;}}//测试代码//参数含义分别是日期后自增长数的位数, 存储的文件名称, 日期与自增长数的分割数$obj = new FileEveryDaySerialNumber(6,"EveryDaySerialNumber.dat",",");$current_date = date("Ymd");$orderNum = $obj->getOrUpdateNumber($current_date,1);//生成的订单号保存于pid.log文件中$handle = fopen("pid.log","a");fwrite($handle,$orderNum."\n");fclose($handle);?>