微信支付--预支付（统一下单）

微信官方文档：https://pay.weixin.qq.com/wiki/doc/api/native.php?chapter=9_1

1.按照微信官方文档统一下单接口的描述,将请求参数放入Map

protected Map<String, Object>  processPost(HttpServletRequest request, HttpServletResponse response) throws BaseException {        String attach = ConvertUtil.getTrimStringFromRequestParam(request, "attach", "");        String device_info = ConvertUtil.getTrimStringFromRequestParam(request, "device_info", WXPayConstants.DEVICE_INFO_DEFAULT.WEB.toString());        String body = ConvertUtil.getNonEmptyStringFromRequestParam(request, "body");        String detail = ConvertUtil.getTrimStringFromRequestParam(request, "detail", "");        String out_trade_no = ConvertUtil.getNonEmptyStringFromRequestParam(request, "out_trade_no");        String total_fee = ConvertUtil.getNonEmptyStringFromRequestParam(request, "total_fee");        String trade_type = ConvertUtil.getTrimStringFromRequestParam(request, "trade_type", WXPayConstants.TRADE_TYPE.JSAPI.toString());        String product_id = ConvertUtil.getNonEmptyStringFromRequestParam(request, "product_id");        String openid = ConvertUtil.getNonEmptyStringFromRequestParam(request, "openid");        Map<String, Object> parametersMap = CommonUtils.createMap("appid", WXPayConstants.APP_ID);//appid        CommonUtils.generateMap(parametersMap, "attach", attach);//附加数据        CommonUtils.generateMap(parametersMap, "mch_id", WXPayConstants.PAY_STORE_ID);//商户号        CommonUtils.generateMap(parametersMap, "device_info", device_info);//设备号 自定义参数，可以为终端设备号(门店号或收银设备ID)，PC网页或公众号内支付可以传"WEB"        CommonUtils.generateMap(parametersMap, "nonce_str", WXPayUtil.generateNonceStr());        CommonUtils.generateMap(parametersMap, "sign_type", WXPayConstants.SignType.MD5);        CommonUtils.generateMap(parametersMap, "body", body);//商品描述        CommonUtils.generateMap(parametersMap, "detail", detail);//商品详情        CommonUtils.generateMap(parametersMap, "out_trade_no", out_trade_no);//自己系统的订单号        CommonUtils.generateMap(parametersMap, "fee_type", WXPayConstants.FEE_TYPE.CNY);        CommonUtils.generateMap(parametersMap, "total_fee", total_fee);//单位位分        CommonUtils.generateMap(parametersMap, "spbill_create_ip", CommonUtils.getIpAddr(request));        CommonUtils.generateMap(parametersMap, "notify_url", WXPayConstants.NOTIFY_URL);        CommonUtils.generateMap(parametersMap, "trade_type", trade_type);        CommonUtils.generateMap(parametersMap, "product_id", product_id);//商品id        CommonUtils.generateMap(parametersMap, "openid", openid);//open id        return WechatService.prepayId(parametersMap);    }

2.用微信自带的工具类对map进行加密并获取签名

/**     * 统一支付（获取预支付id）     * @param     * @return     * @author lichenyi     * @date 2017-8-25 0025 10:44     */    public static Map<String, Object>  prepayId(Map<String, Object> parametersMap) throws HttpRequestFailedException, MD5Exception {        String resultString = null;        try {            String parameterXML = WXPayUtil.generateSignedXml(parametersMap);            //wechat origin code            WXPayRequest wxPayRequest = new WXPayRequest(new WXPayConfigBean());            resultString = wxPayRequest.requestWithoutCert(WXPayConstants.UNIFIEDORDER_URL_SUFFIX, WXPayUtil.generateNonceStr(), parameterXML, false);            logger.info("【预支付订单信息】 --> "+WXPayUtil.xmlToMap(resultString));            return WXPayUtil.xmlToMap(resultString);        } catch (Exception e) {            e.printStackTrace();        }        return null;    }

写的粗糙，有疑问，可以留言。

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