小程序访问地址：payfee.php 如果使用TP框架处理后台的话，写成方法即可
include 'WeixinPay.php';$appid=''; //小程序appid$openid= $_POST['id'];$mch_id=''; //微信支付商户支付号$key=''; //Api密钥$out_trade_no = $mch_id. time();$total_fee = $_POST['fee'];if (empty($total_fee)) { //押金 $body = "充值押金"; $total_fee = floatval(99*100);} else { $body = "充值余额"; $total_fee = floatval($total_fee*100); }$weixinpay = new WeixinPay($appid,$openid,$mch_id,$key,$out_trade_no,$body,$total_fee);$return=$weixinpay->pay();echo json_encode($return);WeixinPay.php微信小程序支付类 所有微信小程序需要的参数都已经写入
/* * 小程序微信支付 */class WeixinPay { protected $appid; protected $mch_id; protected $key; protected $openid; protected $out_trade_no; protected $body; protected $total_fee; function __construct($appid, $openid, $mch_id, $key,$out_trade_no,$body,$total_fee) { $this->appid = $appid; $this->openid = $openid; $this->mch_id = $mch_id; $this->key = $key; $this->out_trade_no = $out_trade_no; $this->body = $body; $this->total_fee = $total_fee; } public function pay() { //统一下单接口 $return = $this->weixinapp(); return $return; } //统一下单接口 private function unifiedorder() { $url = 'https://api.mch.weixin.qq.com/pay/unifiedorder'; $parameters = array( 'appid' => $this->appid, //小程序ID 'mch_id' => $this->mch_id, //商户号 'nonce_str' => $this->createNoncestr(), //随机字符串// 'body' => 'test', //商品描述 'body' => $this->body,// 'out_trade_no' => '2018013106125348', //商户订单号 'out_trade_no'=> $this->out_trade_no,// 'total_fee' => floatval(0.01 * 100), //总金额 单位 分 'total_fee' => $this->total_fee, 'spbill_create_ip' => $_SERVER['REMOTE_ADDR'], //终端IP // 'spbill_create_ip' => '192.168.0.161', //终端IP 'notify_url' => 'https://www.weixin.qq.com/wxpay/notify.php', //通知地址 确保外网能正常访问 'openid' => $this->openid, //用户id 'trade_type' => 'JSAPI'//交易类型 ); //统一下单签名 $parameters['sign'] = $this->getSign($parameters); $xmlData = $this->arrayToXml($parameters); $return = $this->xmlToArray($this->postXmlCurl($xmlData, $url, 60)); return $return; } private static function postXmlCurl($xml, $url, $second = 30) { $ch = curl_init(); //设置超时 curl_setopt($ch, CURLOPT_TIMEOUT, $second); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE); //严格校验 //设置header curl_setopt($ch, CURLOPT_HEADER, FALSE); //要求结果为字符串且输出到屏幕上 curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE); //post提交方式 curl_setopt($ch, CURLOPT_POST, TRUE); curl_setopt($ch, CURLOPT_POSTFIELDS, $xml); curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 20); curl_setopt($ch, CURLOPT_TIMEOUT, 40); set_time_limit(0); //运行curl $data = curl_exec($ch); //返回结果 if ($data) { curl_close($ch); return $data; } else { $error = curl_errno($ch); curl_close($ch); throw new WxPayException("curl出错，错误码:$error"); } } //数组转换成xml private function arrayToXml($arr) { $xml = "<xml>"; foreach ($arr as $key => $val) { if (is_array($val)) { $xml .= "<" . $key . ">" . arrayToXml($val) . "</" . $key . ">"; } else { $xml .= "<" . $key . ">" . $val . "</" . $key . ">"; } } $xml .= "</xml>"; return $xml; } //xml转换成数组 private function xmlToArray($xml) { //禁止引用外部xml实体 libxml_disable_entity_loader(true); $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA); $val = json_decode(json_encode($xmlstring), true); return $val; } //微信小程序接口 private function weixinapp() { //统一下单接口 $unifiedorder = $this->unifiedorder();// print_r($unifiedorder); $parameters = array( 'appId' => $this->appid, //小程序ID 'timeStamp' => '' . time() . '', //时间戳 'nonceStr' => $this->createNoncestr(), //随机串 'package' => 'prepay_id=' . $unifiedorder['prepay_id'], //数据包 'signType' => 'MD5'//签名方式 ); //签名 $parameters['paySign'] = $this->getSign($parameters); return $parameters; } //作用：产生随机字符串，不长于32位 private function createNoncestr($length = 32) { $chars = "abcdefghijklmnopqrstuvwxyz0123456789"; $str = ""; for ($i = 0; $i < $length; $i++) { $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1); } return $str; } //作用：生成签名 private function getSign($Obj) { foreach ($Obj as $k => $v) { $Parameters[$k] = $v; } //签名步骤一：按字典序排序参数 ksort($Parameters); $String = $this->formatBizQueryParaMap($Parameters, false); //签名步骤二：在string后加入KEY $String = $String . "&key=" . $this->key; //签名步骤三：MD5加密 $String = md5($String); //签名步骤四：所有字符转为大写 $result_ = strtoupper($String); return $result_; } ///作用：格式化参数，签名过程需要使用 private function formatBizQueryParaMap($paraMap, $urlencode) { $buff = ""; ksort($paraMap); foreach ($paraMap as $k => $v) { if ($urlencode) { $v = urlencode($v); } $buff .= $k . "=" . $v . "&"; } $reqPar = ''; if (strlen($buff) > 0) { $reqPar = substr($buff, 0, strlen($buff) - 1); } return $reqPar; }}小程序页面请求处理：
wx.request({ url: 'https://yourhost.com/wxpay/payfee.php',//改成你自己的链接 data:{ id: app.globalData.openid,//获取用户openid fee:100 //商品价格 }, header: { 'Content-Type': 'application/x-www-form-urlencoded' }, method: 'POST', success: function (res) { console.log(res.data); console.log('调起支付'); wx.requestPayment({ 'timeStamp': res.data.timeStamp, 'nonceStr': res.data.nonceStr, 'package': res.data.package, 'signType': 'MD5', 'paySign': res.data.paySign, 'success': function (res) { console.log('success'); wx.showToast({ title: '支付成功', icon: 'success', duration: 3000 }); }, 'fail': function (res) { console.log(res); }, 'complete': function (res) { console.log('complete'); } }); }, fail: function (res) { console.log(res.data) } });回调URL：notify.php
$postXml = $GLOBALS["HTTP_RAW_POST_DATA"]; //接收微信参数 // 接受不到参数可以使用file_get_contents("php://input"); PHP高版本中$GLOBALS好像已经被废弃了if (empty($postXml)) { return false;} //将xml格式转换成数组function xmlToArray($xml) { //禁止引用外部xml实体 libxml_disable_entity_loader(true); $xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA); $val = json_decode(json_encode($xmlstring), true); return $val;}$attr = xmlToArray($postXml);$total_fee = $attr['total_fee'];$open_id = $attr['openid'];$out_trade_no = $attr['out_trade_no'];$time = $attr['time_end'];So：在微信的异步通知后，也需要给微信服务器，返回一个信息，只不过微信的所有数据格式都是xml的，所以我们在返回一个数据给微信即可。
echo exit('<xml><return_code><![CDATA[SUCCESS]]></return_code><return_msg><![CDATA[OK]]></return_msg></xml>');
