php实现根据IP地址获取其所在省市的方法

function getiplookup($ip = ''){  
  if(empty($ip)){  
    return '请输入ip地址'; 
  }  
  $res = @file_get_contents('http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=js&ip=' . $ip);  
  if(empty($res)){ return false; }  
  $jsonmatches = array();  
  preg_match('#{.+?}#', $res, $jsonmatches);  
  if(!isset($jsonmatches[0])){ return false; }  
  $json = json_decode($jsonmatches[0], true);  
  if(isset($json['ret']) && $json['ret'] == 1){  
    $json['ip'] = $ip;  
    unset($json['ret']);  
  }else{  
    return false;  
  }  
  return $json;  
} 
$ipinfos = getiplookup('123.125.114.144'); //baidu.com ip地址  
var_dump($ipinfos); 

function getipaddress(){  
  $ipcontent  = file_get_contents("http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=js");  
  $jsondata = explode("=",$ipcontent);   
  $jsonaddress = substr($jsondata[1], 0, -1);  
  return $jsonaddress;  
}  
$ip_info=json_decode(getipaddress());