php 获取链接参数

private function getQuerystr($url,$key){

$res = '';

$a = strpos($url,'?');

if($a!==false){

$str = substr($url,$a+1);

$arr = explode('&',$str);

foreach($arr as $k=>$v){

$tmp = explode('=',$v);

if(!empty($tmp[0]) && !empty($tmp[1])){

$barr[$tmp[0]] = $tmp[1];

}

}

}

if(!empty($barr[$key])){

$res = $barr[$key];

}

return $res;

}