<?php
class wxPay {
  //配置参数信息
  const SHANGHUHAO = "1430998xxx";//商户号
  const PARTNERKEY = "leFyTOXWzUEXxfp47WOu5d9xxxxxx";  //api，商户后台
  //核心支付函数,参数：请求地址和参数
  function pay($url,$obj) {
    $obj['nonce_str'] = $this->create_noncestr();  //创建随机字符串
    $stringA = $this->create_qianming($obj,false);  //创建签名
    $stringSignTemp = $stringA."&key=leFyTOXWzUEXxfp47WOu5xxxxxx";  //签名后加api
    $sign = strtoupper(md5($stringSignTemp));  //签名加密并大写
    $obj['sign'] = $sign;  //将签名传入数组
    $postXml = $this->arrayToXml($obj);  //将参数转为xml格式
    var_dump($postXml);
    $responseXml = $this->curl_post_ssl($url,$postXml);  //提交请求
    var_dump($responseXml);
    return $responseXml;
  }
  //生成签名,参数：生成签名的参数和是否编码
  function create_qianming($arr,$urlencode) {
    $buff = "";
    ksort($arr); //对传进来的数组参数里面的内容按照字母顺序排序，a在前面，z在最后（字典序）
    foreach ($arr as $k=>$v) {
      if(null!=$v && "null" != $v && "sign" != $k) {  //签名不要转码
        if ($urlencode) {
          $v = urlencode($v);
        }
        $buff.=$k."=".$v."&";
      }
    }
    if (strlen($buff)>0) {
      $reqPar = substr($buff,0,strlen($buff)-1); //去掉末尾符号“&”
    }
    return $reqPar;
  }
  //生成随机字符串，默认32位
  function create_noncestr($length=32) {
    //创建随机字符
    $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
    $str = "";
    for($i=0;$i<$length;$i++) {
      $str.=substr($chars, mt_rand(0,strlen($chars)-1),1);
    }
    return $str;
  }
  //数组转xml
  function arrayToXml($arr) {
    $xml = "<xml>";
    foreach ($arr as $key=>$val) {
      if (is_numeric($val)) {
        $xml.="<".$key.">".$val."</".$key.">";
      } else {
        $xml.="<".$key."><![CDATA[".$val."]]></".$key.">";
      }
    }
    $xml.="</xml>";
    return $xml;
  }
  //post请求网站，需要证书
  function curl_post_ssl($url, $vars, $second=30,$aHeader=array())
  {
    $ch = curl_init();
    //超时时间
    curl_setopt($ch,CURLOPT_TIMEOUT,$second);
    curl_setopt($ch,CURLOPT_RETURNTRANSFER, 1);
    //这里设置代理，如果有的话
    curl_setopt($ch,CURLOPT_URL,$url);
    curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,false);
    curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,false);
    //cert 与 key 分别属于两个.pem文件
    //请确保您的libcurl版本是否支持双向认证，版本高于7.20.1
    curl_setopt($ch,CURLOPT_SSLCERT,dirname(__FILE__).DIRECTORY_SEPARATOR.
        'zhengshu'.DIRECTORY_SEPARATOR.'apiclient_cert.pem');
    curl_setopt($ch,CURLOPT_SSLKEY,dirname(__FILE__).DIRECTORY_SEPARATOR.
        'zhengshu'.DIRECTORY_SEPARATOR.'apiclient_key.pem');
    curl_setopt($ch,CURLOPT_CAINFO,dirname(__FILE__).DIRECTORY_SEPARATOR.
        'zhengshu'.DIRECTORY_SEPARATOR.'rootca.pem');
    if( count($aHeader) >= 1 ){
      curl_setopt($ch, CURLOPT_HTTPHEADER, $aHeader);
    }
    curl_setopt($ch,CURLOPT_POST, 1);
    curl_setopt($ch,CURLOPT_POSTFIELDS,$vars);
    $data = curl_exec($ch);
    if($data){
      curl_close($ch);
      return $data;
    }
    else {
      $error = curl_errno($ch);
      echo "call faild, errorCode:$error\n";
      curl_close($ch);
      return false;
    }
  }
}

<?php
require 'wxpay.class.php';<br><br>//数组参数
$money = 100; //最低1元，单位分
$sender = "晨缘房产";
$obj2 = array();
$obj2['wxappid'] = ""; //appid
$obj2['mch_id'] = "";　　//商户id
$obj2['mch_billno'] = "商户id".date('YmdHis').rand(1000,9999);　　//组合成28位，根据官方开发文档，可以自行设置
$obj2['client_ip'] = $_SERVER['REMOTE_ADDR'];
$obj2['re_openid'] = "oUxO6v26wdyMHThD9kfDW6NB_xbE";　　//接收红包openid
$obj2['total_amount'] = $money;
$obj2['min_value'] = $money;
$obj2['max_value'] = $money;
$obj2['total_num'] = 1;
$obj2['nick_name'] = $sender;
$obj2['send_name'] = $sender;
$obj2['wishing'] = "恭喜发财";
$obj2['act_name'] = $sender."红包";
$obj2['remark'] = $sender."红包";
$url = "https://api.mch.weixin.qq.com/mmpaymkttransfers/sendredpack";
$wxpay = new wxPay();
$res = $wxpay->pay($url, $obj2);
var_dump($res);