如何用php抓取网页中邮箱地址代码

<?php
    /**
    desc：采集网页中的邮箱的代码
    */
    $url='http://www.xxx.net'; //要采集的网址 
    $content=file_get_contents($url);
    //echo $content;
    function getEmail($str) {
    //$pattern = "/([a-z0-9]*[-_\.]?[a-z0-9]+)*@([a-z0-9]*[-_]?[a-z0-9]+)+[\.][a-z]{2,3}([\.][a-z]{2})?/i";
    $pattern = "/([a-z0-9\-_\.]+@[a-z0-9]+\.[a-z0-9\-_\.]+)/";
    preg_match_all($pattern,$str,$emailArr);
 
    return $emailArr[0];
    }
    print_r( getEmail($content));
    ?>