一下是官方的php  demo， 我把$post_data['client_id']  和 $post_data['client_secret']   改成自己的，其他没变，怎么返回bool(false)呢？？？

function request_post($url = '', $param = '') {
if (empty($url) || empty($param)) {
return false;
}

$postUrl = $url;
$curlPost = $param;
$curl = curl_init();//初始化curl
curl_setopt($curl, CURLOPT_URL,$postUrl);//抓取指定网页
curl_setopt($curl, CURLOPT_HEADER, 0);//设置header
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);//要求结果为字符串且输出到屏幕上
curl_setopt($curl, CURLOPT_POST, 1);//post提交方式
curl_setopt($curl, CURLOPT_POSTFIELDS, $curlPost);
$data = curl_exec($curl);//运行curl
curl_close($curl);

return $data;
}

$url = 'https://aip.baidubce.com/oauth/2.0/token';
$post_data['grant_type'] = 'client_credentials';
$post_data['client_id'] = '你的 Api Key';
$post_data['client_secret'] = '你的 Secret Key';
$o = "";
foreach ( $post_data as $k => $v )
{
$o.= "$k=" . urlencode( $v ). "&" ;
}
$post_data = substr($o,0,-1);

$res = request_post($url, $post_data);

var_dump($res);

?>