php 微信公众号支付

<?php

class wxPay
{

/*
    微信jsapi支付相关配置
*/
protected $key = 'c2a7d232222222222e795';  //商户号API KEY  在商户后台设置
protected $appid = 'wxbb82111119f5e5f04';  //公众号appid
protected $mchid = '11111111';          //商户号


/*
    微信JSAPI支付
    body 
    out_trade_no  外部订单号 （自己生成的订单号）
    total_fee     支付的金额
    notify_url    支付成功后的回调
    openid        用户对应公众号的openid
    
*/
public function jsApiPay($params)
{
    $postData = array();
    $postData['appid']  = $this->appid;
    $postData['mch_id']     = $this->mchid;
    $postData['nonce_str'] = $this->createNoncestr();
    $postData['body']   = $params['body']?$params['body']:'jsapi支付';   
    $postData['out_trade_no']   = $params['out_trade_no'];      
    $postData['total_fee']  = $params['total_fee'];  
    $postData["spbill_create_ip"] = $_SERVER["REMOTE_ADDR"]; 
    $postData['notify_url'] = $params['notify_url'];
    $postData['trade_type'] = 'JSAPI';
    $postData['openid'] = $params['openid'];
    $postData["sign"] = $this->createSign($postData); 

    //把数组转化成xml格式
    $xmlData = $this->arrayToXml($postData);
    $resXml = $this->curl_post('https://api.mch.weixin.qq.com/pay/unifiedorder', $xmlData); 
    $resData = json_decode(json_encode(simplexml_load_string($resXml, 'SimpleXMLElement', LIBXML_NOCDATA)), true);
    if($resData['return_code']!='SUCCESS' || $resData['result_code']!='SUCCESS') return false;    

    // 生成正式支付参数
    $data = array(
        'appId'=> $resData['appid'],
        'nonceStr'=> $resData['nonce_str'],
        'package'=> "prepay_id=" . $resData['prepay_id'],
        'signType'=> 'MD5',
        'timeStamp'=> time(),
    );        
    //支付签名
    $data['paySign'] = $this->createSign($data);
    return $data;

}

//生成签名
private function createSign($params)
{
    //签名步骤一：按字典序排序参数
    ksort($params);
    $String = $this->formatBizQueryParaMap($params, 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_;

}

//按字典序排序参数
private function formatBizQueryParaMap($params,$urlencode=false)
{
    ksort($params);
    $buff = '';
    foreach($params as $key=>$val)
    {
        $buff .= $key . "=" . $val . "&";
    }
    $reqPar = substr($buff, 0, strlen($buff)-1);
    return $reqPar;
}

//将数组转换为xml格式 
private 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;
}


//随机字符串
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;
}  


}


//调用
$obj = new wxPay()
$params = array();
$params['out_trade_no'] = date('YmdHis');
$params['total_fee'] = 100;
$params['notify_url'] = 'http://www.xxx.com/mobile/notify.php';
$params['openid'] = 'ouD322auhn9o5m-8';
$res = $obj->jsApiPay($params);

?>

如果一直报签名错误， 可以先到签名工具里对签名进行验证。 如果在签名工具里校验签名是正确的，那很有可能是api key的问题，重新在商户后台 ，设置一下api key，一般就可以正常了