//$ak开发密钥,$cityname城市名称(支持省县乡详细地址)
public function getposition($ak,$cityname){
$callback=array('lng'=>0,'lat'=>0);
$apiUrl='http://api.map.baidu.com/geocoder/v2/?address='.$cityname.'&output=json&ak='.$ak;
$ret=json_decode(file_get_contents($apiUrl),true);
if($ret['status']==0){
$callback['lng']=$ret['result']['location']['lng'];
$callback['lat']=$ret['result']['location']['lat'];
}
return $callback;
}