PHP调用接口用post方法传送json数据

<?php
require("helper.php");
header('content-type:text/html;charset=utf-8');

$key = 'C43D436036E643F5AFA654FED758BCF7';

//参数数组
$post_data = array (
    "parter" => '2308',
    "orderid" => '201711021121',
);

//签名
ksort($post_data);//键按ASCII码升序排序
$preSignString=getPreSignString($post_data);
$sign = md5($preSignString.'&key='.$key);
$sign=strtoupper($sign);//大写

//签名参数添加到参数数组
$post_data['sign']=$sign;

//参数转成json
$parameters =json_encode($post_data);

//发送请求
$url='http://localhost:64781/api/Query/QueryStatus';
$ch = curl_init();
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POSTFIELDS, $parameters);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);
curl_close($ch);

//处理返回数据
$responseData=json_decode($response,true);//发序列化为数组

print_r($responseData);

<?php

/*
 * 获取待签名字符串
 * */
function getPreSignString($array)
{
    $prestr='';

    if(empty($array))
        return $prestr;
    else
    {
        foreach($array as $key=>$value){
            if(!empty(trim($value)) && strtolower($key)!='sign') {
                $prestr.=$key.'='.$value.'&';
            }
        }

        if(!empty($prestr)){
            $length=strlen($prestr);
            $prestr=substr($prestr,0,$length-1);//去掉最后一个‘&’
        }

        return $prestr;
    }
}

Stream requestData = HttpContext.Current.Request.InputStream;
 //获取参数
 byte[] b = new byte[requestData.Length];
 requestData.Read(b, 0, (int)requestData.Length);
 string postdata = Encoding.UTF8.GetString(b);