PHP應用
<a href="{:U('Wxpay/js_api_start',array('order_key_num'=>$v['order_key_num]))}"> 微信支付</a>

PHP應用
<?php
namespace Home\Controller;
use Think\Controller;
//微信支付類
class WxpayController extends Controller {
 //獲取access_token過程中的跳轉uri,通過跳轉將code傳入jsapi支付頁面
 public function js_api_start(){
  if(!empty($_GET['order_key_num'])){
   // session(array('pay_now_id'=>$_GET['order_key_num'],'expire'=>3600));
   S('pay_now_id',$_GET['order_key_num'],3600);
  }
  vendor('Weixinpay.WxPayPubHelper');
  //使用jsapi接口
  $jsApi = new \JsApi_pub();
  //=========步驟1：網(wǎng)頁授權獲取用戶openid============
  //通過code獲得openid
   if($_GET['code'] == ''){
   //跳轉
    $redirect_uri = 'https://當前域名+模塊+控制器+方法';
    $url = 'https://open.weixin.qq.com/connect/oauth2/authorize
    ?appid=公眾號特有IDredirect_uri='.$redirect_uri.'&response_type=code&scope=snsapi_base&state=STATE#wechat_redirect';
    header("Location: $url");
    exit();
   }else{
   //獲取openid
   $url = 'https://api.weixin.qq.com/sns/oauth2/access_token
   ?appid=公眾號ID&secret=公眾號scrept&code='.$_GET['code'].'&grant_type=authorization_code'; 
   $openid_arr = json_decode(file_get_contents($url),true);
  }
  $openid=$openid_arr['openid'];
  $pay_now_id = S('pay_now_id');
  if($pay_now_id){
   $id=$pay_now_id;
   $o = D('order_info');
   $order_info = $o->where('order_id = %d',$id)->find();
   if(empty($order_info['paycode'])){
    $order_info['paycode'] = 'weixin';
   }
   if($order_info['is_pay']){
    $this->error('當前訂單已經(jīng)支付');
   }
  }else{
   $this->error("不存在當前訂單編號!");
  }
   $res = array(
   'order_sn' => $order_info['order_sn'],
   'order_amount' => $order_info['pay_money']
   );
  //=========步驟2：使用統(tǒng)一支付接口,獲取prepay_id============
  //使用統(tǒng)一支付接口
  $unifiedOrder = new \UnifiedOrder_pub();
  //設置統(tǒng)一支付接口參數(shù)
  //設置必填參數(shù)
  //appid已填,商戶無需重復填寫
  //mch_id已填,商戶無需重復填寫
  //noncestr已填,商戶無需重復填寫
  //spbill_create_ip已填,商戶無需重復填寫
  //sign已填,商戶無需重復填寫
  $total_fee = $order_info['pay_money']*100;
  // $total_fee = $res['order_amount'];
  //$total_fee = 1;
  // var_dump($order_info['pay_money']);die;
  $body = "訂單支付";
  $unifiedOrder->setParameter("openid", "$openid");//用戶標識
  $unifiedOrder->setParameter("body", '商品采購');//商品描述
  //自定義訂單號,此處僅作舉例
  $unifiedOrder->setParameter("out_trade_no", $order_info['order_sn']);//商戶訂單號 
  $unifiedOrder->setParameter("total_fee", $total_fee);//總金額
  //$unifiedOrder->setParameter("attach", "order_sn={$res['order_sn']}");//附加數(shù)據(jù) 
  $unifiedOrder->setParameter("notify_url", \WxPayConf_pub::NOTIFY_URL);//通知地址 
  $unifiedOrder->setParameter("trade_type", "JSAPI");//交易類型
  //非必填參數(shù),商戶可根據(jù)實際情況選填
  //$unifiedOrder->setParameter("sub_mch_id","XXXX");//子商戶號 
  //$unifiedOrder->setParameter("device_info","XXXX");//設備號 
  //$unifiedOrder->setParameter("attach","XXXX");//附加數(shù)據(jù) 
  //$unifiedOrder->setParameter("time_start","XXXX");//交易起始時間
  //$unifiedOrder->setParameter("time_expire","XXXX");//交易結束時間 
  //$unifiedOrder->setParameter("goods_tag","XXXX");//商品標記 
  //$unifiedOrder->setParameter("openid","XXXX");//用戶標識
  //$unifiedOrder->setParameter("product_id","XXXX");//商品ID
  $prepay_id = $unifiedOrder->getPrepayId();
  // var_dump($prepay_id);die;
  //=========步驟3：使用jsapi調起支付============
  $jsApi->setPrepayId($prepay_id);
  $jsApiParameters = $jsApi->getParameters();
  $wxconf = json_decode($jsApiParameters, true);
  if ($wxconf['package'] == 'prepay_id=') {
   $this->error('當前訂單存在異常!');
  }
  $this->assign('res', $res);
  $this->assign('jsApiParameters', $jsApiParameters);
  $this->display('jsapi');
 }
 //異步通知url,商戶根據(jù)實際開發(fā)過程設定
 public function notify_url() {
  vendor('Weixinpay.WxPayPubHelper');
  //使用通用通知接口
  $notify = new \Notify_pub();
  //存儲微信的回調
  $xml = $GLOBALS['HTTP_RAW_POST_DATA']; 
  $notify->saveData($xml);
  //驗證簽名,并回應微信.
  //對后臺通知交互時,如果微信收到商戶的應答不是成功或超時,微信認為通知失敗,
  //微信會通過一定的策略(如30分鐘共8次)定期重新發(fā)起通知,
  //盡可能提高通知的成功率,但微信不保證通知最終能成功.
  if($notify->checkSign() == FALSE){
   $notify->setReturnParameter("return_code", "FAIL");//返回狀態(tài)碼
   $notify->setReturnParameter("return_msg", "簽名失敗");//返回信息
  }else{
   $notify->setReturnParameter("return_code", "SUCCESS");//設置返回碼
  }
  $returnXml = $notify->returnXml();
  //==商戶根據(jù)實際情況設置相應的處理流程,此處僅作舉例=======
  //以log文件形式記錄回調信息
  //$log_name = "notify_url.log";//log文件路徑
  //$this->log_result($log_name, "【接收到的notify通知】:\n".$xml."\n");
  $parameter = $notify->xmlToArray($xml);
  //$this->log_result($log_name, "【接收到的notify通知】:\n".$parameter."\n");
  if($notify->checkSign() == TRUE){
   if ($notify->data["return_code"] == "FAIL") {
    //此處應該更新一下訂單狀態(tài),商戶自行增刪操作
    //$this->log_result($log_name, "【通信出錯】:\n".$xml."\n");
    //更新訂單數(shù)據(jù)【通信出錯】設為無效訂單
    echo 'error';
   }
   else if($notify->data["result_code"] == "FAIL"){
    //此處應該更新一下訂單狀態(tài),商戶自行增刪操作
    //$this->log_result($log_name, "【業(yè)務出錯】:\n".$xml."\n");
    //更新訂單數(shù)據(jù)【通信出錯】設為無效訂單
    echo 'error';
   }
   else{
    //$this->log_result($log_name, "【支付成功】:\n".$xml."\n");
    //我這里用到一個process方法,成功返回數(shù)據(jù)后處理,返回地數(shù)據(jù)具體可以參考微信的文檔
    if ($this->process($parameter)) {
     //處理成功后輸出success,微信就不會再下發(fā)請求了
     echo 'success';
    }else {
     //沒有處理成功,微信會間隔的發(fā)送請求
     echo 'error';
    }
   }
  }
 }
 //訂單處理
 private function process($parameter) {
  //此處應該更新一下訂單狀態(tài),商戶自行增刪操作
  /*
  * 返回的數(shù)據(jù)最少有以下幾個
  * $parameter = array(
   'out_trade_no' => xxx,//商戶訂單號
   'total_fee' => XXXX,//支付金額
   'openid' => XXxxx,//付款的用戶ID
  );
  */
  $data = array(
      'order_sn'=>$parameter['out_trade_no'],
      'des'=>('訂單交易：'.$parameter['out_trade_no']),
      'money'=>$parameter['total_fee'],
     );
  orderhandlestarysdgdss($data);//這是一個common方法,他會將該訂單狀態(tài)設置為已支付之類的
  return true;
 }
}
?>

PHP應用
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0;" name="viewport" />
<meta name="format-detection" content="telephone=no"/> 
<title>下</title>
<meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">
<meta name="keyword" content="">
<meta name="description" content="">
<script type="text/javascript">
var order_sn = "{$res['order_sn']}";
//調用微信JS api 支付
function jsApiCall(){
 WeixinJSBridge.invoke(
  'getBrandWCPayRequest',
  <?php echo $jsApiParameters; ?>,
  function(res){
   //如果支付成功
   if (res.err_msg == 'get_brand_wcpay_request:ok') {
    //支付成功后跳轉的地址
    location.href = "{:U('Home/User/my_order')}";
   }else if (res.err_msg == 'get_brand_wcpay_request:cancel') {
    alert('請盡快完成支付哦!');
   }else if (res.err_msg == 'get_brand_wcpay_request:fail') {
    alert('支付失敗');
   }else {
    alert('意外錯誤');
   }
   //WeixinJSBridge.log(res.err_msg);
   //alert(res.err_code+res.err_desc+res.err_msg);
   /*if (res.err_msg == 'get_brand_wcpay_request:ok') {
    alert('支付成功');
   }else {
    alert('取消支付');
   }*/
  }
 );
}
function callpay(){
 if (typeof WeixinJSBridge == "undefined"){
  if( document.addEventListener ){
   document.addEventListener('WeixinJSBridgeReady', jsApiCall, false);
  }else if (document.attachEvent){
   document.attachEvent('WeixinJSBridgeReady', jsApiCall); 
   document.attachEvent('onWeixinJSBridgeReady', jsApiCall);
  }
 }else{
  jsApiCall();
 }
}
</script>
<style>
*{font-family:'微軟雅黑','Microsoft YaHei';}
body #head{position:relative;z-index:99999999999999;padding:0 10px;}
body .zh-head{padding:0 0 0 0;height:auto;}
.zh-head-conter{position:relative;height:40px;}
.zh-logo{position:absolute;left:50%;top:0;margin:0 0 0 -60px;float:none;width:auto;}
.zh-logo a{display:block;}
.zh-logo img{width:120px;height:40px;display:block;}
.heads_fix .zh-logo{}
#head{position:fixed!important;left:0;top:0;right:0;z-index:99999;background:#fff;border-bottom:1px solid #ddd;}
.zh-logo{height:40px;}
.flowpay{margin-top:25%;}
.flowpay dt{text-align:center;}
.flowpay strong.price{font-size:40px;}
.wxLogo{text-align:center;}
.wxLogo img{}
.flowpay dd{margin:0;padding:20px 0 10px 0;}
.flowpay dd input{margin:0 auto;padding:0;width:90%;height:45px;line-height:45px;border:0;border-radius:4px;background:#0CBC0A;color:#fff;font-size:17px;display:block;-webkit-appearance:none;-moz-appearance:none;appearance:none;outline:none;}
</style>
</head>
<body>
<!--頭部開始-->
<div class="flowpay">
 <dl>
  <dt>
   <p class="wxLogo"><img src="__PUBLIC__/home/images/1479953699138120.png" alt=""></p>
   本次訂單需支付：￥<strong class="price">{$res['order_amount']}</strong>?元
  </dt>
  <dd>
   <input type="button" id="hhhhhh" onclick="callpay()" value="立即支付" />
  </dd>
 </dl>
</div>
<!--尾結束-->
</body>
</html>