PHP对接微信支付，发起商家转账API，商家转账到零钱

<?php


namespace app\common\service;

use app\common\exception\BaseException;

class WechatPayTransfer
{
    protected $wxapp = [];

    public function __construct($wxapp)
    {
        $this->wxapp = $wxapp;
    }

    /**
     * 商家转账到零钱
     * @param $batch_name
     * @param $out_trade_no
     * @param $money
     * @param $openid
     * @throws BaseException
     */
    public function transfer($batch_name, $out_trade_no, $money, $openid)
    {
        $url = 'https://api.mch.weixin.qq.com/v3/transfer/batches';
        $pars = [];
        $pars['appid'] = $this->wxapp['app_id'];//直连商户的appid
        $pars['out_batch_no'] = 'batch' . $out_trade_no;//商户系统内部的商家批次单号，要求此参数只能由数字、大小写字母组成，在商户系统内部唯一
        $pars['batch_name'] = $batch_name;//该笔批量转账的名称
        $pars['batch_remark'] = $batch_name;//转账说明，UTF8编码，最多允许32个字符
        $pars['total_amount'] = intval($money * 100);//转账总金额 单位为“分”
        $pars['total_num'] = 1;//转账总笔数
        $pars['transfer_detail_list'][0] = [
            'out_detail_no' => 'transfer' . $out_trade_no,
            'transfer_amount' => $pars['total_amount'],
            'transfer_remark' => $batch_name,
            'openid' => $openid
        ];//转账明细列表
        $token = $this->getToken($pars);//获取token
        $res = $this->https_request($url, json_encode($pars), $token);//发送请求
        $data = json_decode($res, true);
        if(isset($data['batch_id']) && $data['batch_id']){
            return $data;
        }
        return [];
    }

    function https_request($url, $data = null, $token)
    {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, (string)$url);
        curl_setopt($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);
        //添加请求头
        $headers = [
            'Authorization:WECHATPAY2-SHA256-RSA2048 ' . $token,
            'Accept: application/json',
            'Content-Type: application/json; charset=utf-8',
            'User-Agent:Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36',
        ];
        if (!empty($headers)) {
            curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
        }
        $output = curl_exec($curl);
        curl_close($curl);
        return $output;
    }

    public function getToken($pars)
    {
        // $url = 'https://api.mch.weixin.qq.com/v3/certificates';
        $url = 'https://api.mch.weixin.qq.com/v3/transfer/batches';
        $http_method = 'POST';//请求方法（GET,POST,PUT）
        $timestamp = time();//请求时间戳
        $url_parts = parse_url($url);//获取请求的绝对URL
        $nonce = $timestamp . rand('10000', '99999');//请求随机串
        $body = json_encode((object)$pars);//请求报文主体
        $stream_opts = [
            "ssl" => [
                "verify_peer" => false,
                "verify_peer_name" => false,
            ]
        ];
        try {
            $certPem = $this->getCertPem();
            $apiclient_cert_path = $certPem['certPem'];
            $apiclient_key_path = $certPem['keyPem'];
            $apiclient_cert_arr = openssl_x509_parse(file_get_contents($apiclient_cert_path, false, stream_context_create($stream_opts)));
            $serial_no = $apiclient_cert_arr['serialNumberHex'];//证书序列号
            $mch_private_key = file_get_contents($apiclient_key_path, false, stream_context_create($stream_opts));//密钥
            $merchant_id = $this->wxapp['mchid'];
            $canonical_url = ($url_parts['path'] . (!empty($url_parts['query']) ? "?${url_parts['query']}" : ""));
            $message = $http_method . "\n" .
                $canonical_url . "\n" .
                $timestamp . "\n" .
                $nonce . "\n" .
                $body . "\n";
            openssl_sign($message, $raw_sign, $mch_private_key, 'sha256WithRSAEncryption');
            $sign = base64_encode($raw_sign);//签名
            $schema = 'WECHATPAY2-SHA256-RSA2048';
            $token = sprintf('mchid="%s",nonce_str="%s",timestamp="%d",serial_no="%s",signature="%s"',
                $merchant_id, $nonce, $timestamp, $serial_no, $sign);//微信返回token
        } catch (\Exception $e) {
            throw new BaseException(['msg' => $e->getMessage()]);
        }
        return $token;
    }

    /**
     * 获取cert证书文件
     * @return array
     * @throws BaseException
     */
    private function getCertPem()
    {
        if (empty($this->wxapp['cert_pem']) || empty($this->wxapp['key_pem'])) {
            throw new BaseException(['msg' => '请先到后台小程序设置填写微信支付证书文件']);
        }
        // cert目录
        $filePath = dirname(__DIR__) . '/library/wechat/cert/' . $this->wxapp['wxapp_id'] . '/';
        return [
            'certPem' => $filePath . 'cert.pem',
            'keyPem' => $filePath . 'key.pem'
        ];
    }
}

参考上方的类文件，在结合微信官方的接口文档即可，很简单！

微信支付官方文档：​​微信支付-发起商家转账API​​

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