PHP實現微信小程序支付，很基礎，也很容易！

前端代碼

wx.request({
   url: 'https://www.yourhost.com/weixin/WeiActivity/payJoinfee',//改爲你本身的連接
   header: {
     'Content-Type': 'application/x-www-form-urlencoded'
   },
   method:'POST',
   success: function(res) {
     console.log(res.data);
     console.log('調起支付');
     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('fail');
       },
       'complete':function(res){
         console.log('complete');
       }
     });
   },
   fail:function(res){
     console.log(res.data)
   }
 });

後端核心代碼：

//支付費用
 public function payJoinfee(){
 $appid='wx888888888';
 $openid='oCQwY0Q_pzrQpu8888888';
 $mch_id='141388888';
 $key='9A0A86888888888';

 import('Weixin.Lib.WeixinPay');
 $weixinpay = new \WeixinPay($appid,$openid,$mch_id,$key);
 $return=$weixinpay->pay();

 $this->response($return,'json');
 }

微信支付類

<?php
/*
 * 小程序微信支付
 */
class WeixinPay{
 protected $appid;
 protected $mch_id;
 protected $key;
 protected $openid;
 function __construct($appid,$openid,$mch_id,$key){
 $this->appid=$appid;
 $this->openid=$openid;
 $this->mch_id=$mch_id;
 $this->key=$key;
 } 
 public function pay(){
 //統一下單接口
 $return=$this->weixinapp();
 return $return;
 }
 //統一下單接口
 private function unifiedorder(){
 $url='https://api.mch.weixin.qq.com/pay/unifiedorder';
 $parameters=array(
  'appid'=>$this->appid,//小程序ID
  'mch_id'=>$this->mch_id,//商戶號
  'nonce_str'=>$this->createNoncestr(),//隨機字符串
  'body'=>'測試',//商品描述
  'out_trade_no'=>'2015450806125346',//商戶訂單號
  'total_fee'=>floatval(0.01*100),//總金額 單位 分
  'spbill_create_ip'=>$_SERVER['REMOTE_ADDR'],//終端IP
  'notify_url'=>'http://www.weixin.qq.com/wxpay/pay.php',//通知地址
  'openid'=>$this->openid,//用戶id
  'trade_type'=>'JSAPI'//交易類型
 );
 //統一下單簽名
 $parameters['sign']=$this->getSign($parameters);
 $xmlData=arrayToXml($parameters);

 $return=xmlToArray(postXmlSSLCurl($xmlData,$url,60));

 return $return;
 }
 //微信小程序接口
 private function weixinapp(){
 //統一下單接口
 $unifiedorder=$this->unifiedorder();

 $parameters=array(
  'appId'=>$this->appid,//小程序ID
  'timeStamp'=>''.time().'',//時間戳
  'nonceStr'=>$this->createNoncestr(),//隨機串
  'package'=>'prepay_id='.$unifiedorder['prepay_id'],//數據包
  'signType'=>'MD5'//簽名方式
 );
 //簽名
 $parameters['paySign']=$this->getSign($parameters);

 return $parameters;
 }
 //做用：產生隨機字符串，不長於32位
 private function createNoncestr($length = 32 ){
 $chars = "abcdefghijklmnopqrstuvwxyz0123456789"; 
 $str ="";
 for ( $i = 0; $i < $length; $i++ ) { 
  $str.= substr($chars, mt_rand(0, strlen($chars)-1), 1); 
 } 
 return $str;
 }
 //做用：生成簽名
 private function getSign($Obj){
 foreach ($Obj as $k => $v){
  $Parameters[$k] = $v;
 }
 //簽名步驟一：按字典序排序參數
 ksort($Parameters);
 $String = $this->formatBizQueryParaMap($Parameters, false);
 //簽名步驟二：在string後加入KEY
 $String = $String."&key=".$this->key;
 //簽名步驟三：MD5加密
 $String = md5($String);
 //簽名步驟四：全部字符轉爲大寫
 $result_ = strtoupper($String);
 return $result_;
 }
 ///做用：格式化參數，簽名過程須要使用
 private function formatBizQueryParaMap($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;
 }
}

注：本文轉載自【PHP自學中心】微信公衆號