private function getHttpResponseGET($url, $cacert_url)
{
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_HEADER, 0);
// 过滤HTTP头
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
// 显示输出结果
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, true);
//SSL证书认证
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 2);
//严格认证
curl_setopt($curl, CURLOPT_CAINFO, $cacert_url);
//证书地址
$responseText = curl_exec($curl);
//var_dump( curl_error($curl) );//如果执行curl过程中出现异常,可打开此开关,以便查看异常内容
curl_close($curl);
return $responseText;
}