function do_post_request($url,$data,$optional_headers = null)
{
$params = array('http' => array(
'method' => 'POST',
'content' => $data
));
if ($optional_headers !== null) {
$params['http']['header'] = $optional_headers;
}
$ctx = stream_context_create($params);
$fp = @fopen($url,'rb',false,$ctx);
if (!$fp) {
throw new Exception("Problem with $url,$PHP_errormsg");
}
$response = @stream_get_contents($fp);
if ($response === false) {
throw new Exception("Problem reading data from $url,$PHP_errormsg");
}
return $response;
}

//json字符串
$data = "{...}";
//转换成数组
$data=json_decode($data,true);
$postdata = http_build_query($data);
do_post_request("http://localhost",$postdata);