微信小程序支付，一贯的风格，代码复制粘贴就好使，想明白原理，自己看开发文档去
一、前端代码:
1.先写一个可以点击支付的按钮
<view class="chongzhi_button" bindtap="pay">支付</view>
2.开始js代码
pay: function(){//下订单并唤起微信支付var price = '0.01'; //支付金额var openid = ''; //这里传用户openid,怎么获取用户的openid这里就不详细的说了var that = this;wx.request({url: '这里写后端接口地址',data: {price: price,openid: openid},method: "POST",headers: {'Content-Type': 'application/json'},success: function (res) {//客户单发起微信请求wx.requestPayment({'appId': '这里写小程序的appId','timeStamp': res.data.timeStamp,'nonceStr': res.data.nonceStr,'package': res.data.package,'signType': 'MD5','paySign': res.data.paySign,'success': function (res) {wx.showToast({title: '支付成功',duration: 1200})console.log('支付成功');setTimeout(function () {wx.redirectTo({url: '../pay/payok?paymoney=' + that.data.paymoney + '&body=' + that.data.contents})}, 1000);//这里完成跳转},'fail': function (res) {if (res.errMsg == "requestPayment:fail cancel") {wx.showToast({title: '支付取消',duration: 1200})} else {wx.showToast({title: '支付失败',image: '../../images/error.png',duration: 1200})}//支付失败console.log(res);},'complete': function (res) { }})}})
二、然后开始后端代码（这里用PHP代码作为示例，没办法，只会PHP）
代码开始
/*** 小程序支付*/public function Pay(){$fee = 0.01;//举例充值0.01$openid = '填写openid';$appid = '小程序AddId';//这里写小程序AddId$body = '标题'; //这个自己写,微信订单里面显示的是商品名称$mch_id = '你的商户号';$nonce_str = $this->nonce_str();//随机字符串$notify_url = '填写你的回调地址';$out_trade_no = $this->order_number($openid);//商户订单号$spbill_create_ip = '服务器Ip地址';$total_fee = $fee*100;//因为充值金额最小是1 而且单位为分 如果是充值1元所以这里需要*100$trade_type = 'JSAPI';//交易类型 默认//这里是按照顺序的 因为下面的签名是按照顺序 排序错误 肯定出错$post['appid'] = $appid;$post['body'] = $body;$post['mch_id'] = $mch_id;$post['nonce_str'] = $nonce_str; //随机字符串$post['notify_url'] = $notify_url;$post['openid'] = $openid;$post['out_trade_no'] = $out_trade_no;$post['spbill_create_ip'] = $spbill_create_ip; //终端的ip$post['total_fee'] = $total_fee; //总金额 最低为一块钱 必须是整数$post['trade_type'] = $trade_type;$sign = $this->sign($post); //签名$post_xml = '<xml><appid>'.$appid.'</appid><body>'.$body.'</body><mch_id>'.$mch_id.'</mch_id><nonce_str>'.$nonce_str.'</nonce_str><notify_url>'.$notify_url.'</notify_url><openid>'.$openid.'</openid><out_trade_no>'.$out_trade_no.'</out_trade_no><spbill_create_ip>'.$spbill_create_ip.'</spbill_create_ip><total_fee>'.$total_fee.'</total_fee><trade_type>'.$trade_type.'</trade_type><sign>'.$sign.'</sign></xml> ';//统一接口prepay_id$url = 'https://api.mch./pay/unifiedorder';$xml = $this->http_request($url,$post_xml);$array = $this->xml($xml);//全要大写if($array['RETURN_CODE'] == 'SUCCESS' && $array['RESULT_CODE'] == 'SUCCESS'){$time = time();$tmp='';//临时数组用于签名$tmp['appId'] = $appid;$tmp['nonceStr'] = $nonce_str;$tmp['package'] = 'prepay_id='.$array['PREPAY_ID'];$tmp['signType'] = 'MD5';$tmp['timeStamp'] = "$time";$data['state'] = 1;$data['timeStamp'] = "$time";//时间戳$data['nonceStr'] = $nonce_str;//随机字符串$data['signType'] = 'MD5';//签名算法，暂支持 MD5$data['package'] = 'prepay_id='.$array['PREPAY_ID'];//统一下单接口返回的 prepay_id 参数值，提交格式如：prepay_id=*$data['paySign'] = $this->sign($tmp);//签名,具体签名方案参见微信公众号支付帮助文档;$data['out_trade_no'] = $out_trade_no;}else{$data['state'] = 0;$data['text'] = "错误";$data['RETURN_CODE'] = $array['RETURN_CODE'];$data['RETURN_MSG'] = $array['RETURN_MSG'];}echo json_encode($data);}//随机32位字符串private function nonce_str(){$result = '';$str = 'QWERTYUIOPASDFGHJKLZXVBNMqwertyuioplkjhgfdsamnbvcxz';for ($i=0;$i<32;$i++){$result .= $str[rand(0,48)];}return $result;}//生成订单号private function order_number($openid){//date('Ymd',time()).time().rand(10,99);//18位return md5($openid.time().rand(10,99));//32位}//签名 $data要先排好顺序private function sign($data){$stringA = '';foreach ($data as $key=>$value){if(!$value) continue;if($stringA) $stringA .= '&'.$key."=".$value;else $stringA = $key."=".$value;}$wx_key = '支付秘钥';$stringSignTemp = $stringA.'&key='.$wx_key;//申请支付后有给予一个商户账号和密码，登陆后自己设置keyreturn strtoupper(md5($stringSignTemp));}//curl请求啊function http_request($url,$data = null,$headers=array()){$curl = curl_init();if(count($headers)>= 1){curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);}curl_setopt($curl, CURLOPT_URL, $url);curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);if(!empty($data)){curl_setopt($curl, CURLOPT_POST, 1);curl_setopt($curl, CURLOPT_POSTFIELDS, $data);}curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);$output = curl_exec($curl);curl_close($curl);return $output;}//获取xmlprivate function xml($xml){$p = xml_parser_create();xml_parse_into_struct($p, $xml, $vals, $index);xml_parser_free($p); $data = "";foreach ($index as $key=>$value){if($key == 'xml' || $key == 'XML') continue;$tag = $vals[$value[0]]['tag'];$value = $vals[$value[0]]['value'];$data[$tag] = $value;}return $data;}
