Map<String, String> data = new HashMap<String, String>();

data.put("appid","wx9bc*****b8908");  //小程序ID

data.put("mch_id",config.getMchID()); //商户号

data.put("trade_type","JSAPI"); //支付场景 APP 微信app支付 JSAPI 公众号支付  NATIVE 扫码支付

data.put("notify_url",notifyUrl); //回调地址

data.put("spbill_create_ip",config.create_ip); //终端ip 

data.put("total_fee",amount); //订单总金额

data.put("out_trade_no",ordernum); //交易号

data.put("body",gname);

data.put("openid",openid);

data.put("nonce_str",WXPayUtil.generateNonceStr());// 随机字符串小于32位

String s = WXPayUtil.generateSignature(data, config.getKey());  //签名

data.put("sign",s);

Map<String, String> respData = wxpay.unifiedOrder(data);;

                if (respData.get("return_code").equals("SUCCESS")){

                        //返回给APP端的参数，APP端再调起支付接口

String resultCode = respData.get("result_code");

if("SUCCESS".equals(resultCode)){

Map<String, String> daa = new HashMap<>();

daa.put("appId", "wx9bc*****b8908");

daa.put("package", "prepay_id="+respData.get("prepay_id"));

daa.put("nonceStr", WXPayUtil.generateNonceStr());

daa.put("signType", "MD5");

daa.put("timeStamp", String.valueOf(System.currentTimeMillis() / 1000));//单位为秒

daa.put("paySign", WXPayUtil.generateSignature(daa, config.getKey()));

        dataMap.put("data", daa);        //传给前端

}else {

}

}