这里有个坑

  {   
    "code":"PARAM_ERROR",
    "detail":{
        "location":"body",
        "value":7.000000000000001   // 微信金额除不尽出现的问题
             },
        "message":" 无法将 JSON 输入源“\/body\/
                    total_amount”映射到目标字段“转账总金额”中，
                    此字段需要一个合法的 64 位有符号整数"
   }

  　const SSLCERT_PATH = '证书路径';
    const SSLKEY_PATH  = '证书key路径';
    const MCHID        = '商户号';
    const APPID        = 'app_id';
    const KEY          = 'key值';

    /**
     * 付款到微信零钱
     * sOpenid：收款方openid
     * nMoney：转账金额
     */
    public function transfer_batches($sOpenid, $nMoney)
    {
        // 付款到零钱方法url
        $url = 'https://api.mch.weixin.qq.com/v3/transfer/batches';

        // 订单号
        $sOrderId = '测试付款' . time();
        // 转账备注 （微信用户会收到该备注）                                                    
        $tRemark  = '测试付款' . $sOrderId; 
        // 转账金额：微信是分为单位 *100 转换                                             
        $transfer_amount = $nMoney * 100;

        // 转账接收列表设置
        $transfer_detail_list = array(                
            [
                'out_detail_no'   => $sOrderId,                  // 明细单号
                'transfer_amount' => intval($transfer_amount),   // 转账总金额 
                'transfer_remark' => $tRemark,                   // 单条转账备注
                'openid'          => $sOpenid,                   // 收款方openid

                // 'user_name'       => '张三',
                // 转账金额 >= 2,000元，收款用户姓名必填                   
            ],
        );
        // 请求参数设置
        $params = [                                                // 请求参数设置
            'appid'                => self::APPID,                 // 文档顶部定义
            'out_batch_no'         => $sOrderId,                   // 商家批次单号
            'batch_name'           => 'x年x月转账',                 // 转账的名称 
            'batch_remark'         => 'x年x月转账',                 // 转账的备注
            'total_amount'         => intval($transfer_amount),    // 转账总金额
            'total_num'            => 1,                           // 转账总笔数
            'transfer_detail_list' => $transfer_detail_list,       // 转账接收列表
        ];
        // 获取token
        $token        = $this->getToken($params);
        // 发送请求                                    
        $res          = $this->https_request($url, json_encode($params), $token);
        // 反馈数组化  
        $resArr       = json_decode($res, true);                                   

        dump($resArr);
        // 存储转账成功信息或别的操作


        // 成功实例返回值
        {
          "out_batch_no": "plfk2020042013",                        // wx唯一识别号
          "batch_id": "1030000071100999991182020050700019480001",  // 商家批次单号
          "create_time": "2015-05-20T13:29:35.120+08:00"           // 创建时间 
        }
    }


    /**
     * 构造请求
     */
    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;
    }

    /**
     * 获取token
     */
    public function getToken($pars)
    {
        $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,
            ]
        ];

        // 证书路径信息：文档顶部定义
        $apiclient_cert_path = self::SSLCERT_PATH;
        $apiclient_key_path  = self::SSLKEY_PATH;

        $apiclient_cert_arr = openssl_x509_parse(file_get_contents($apiclient_cert_path, false, stream_context_create($stream_opts)));
        // 证书序列号
        $serial_no          = $apiclient_cert_arr['serialNumberHex'];
        // 密钥                                                                   
        $mch_private_key    = file_get_contents($apiclient_key_path, false, stream_context_create($stream_opts));
        // 商户id：文档顶部定义                       
        $merchant_id        = self::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');
        // 签名
        $sign   = base64_encode($raw_sign);                                                                                                                
        $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
        return $token;
    }

​

    public function onTransferBatches($openid, $nMoney)
    {
        // 实例化服务层
        $serviceTransfer = new serviceTransfer();
        // 带参请求：sOpenid（收款方openid）   nMoney（转账金额）
        $result          = $serviceTransfer->transfer_batches($openid, $nMoney);
        return $result;
    }