最近做了支付宝扫码付款：废话不多说：下面开始：
1：开通支付宝商家，登录支付宝开放平台，创建应用-
2、设置应用的私钥和公钥，每个应用都有自己的私钥和公钥。不能混用哦
3、把应用的appid、私钥、公钥和支付宝的公钥、网关URL 写到配置文件或是数据库。供程序调用
4编写zfb支付service类
首先引入jar包
<alipay-version>3.7.73.ALL</alipay-version><dependency><groupId>com.alipay.sdk</groupId><artifactId>alipay-sdk-java</artifactId><version>${alipay-version}</version></dependency>
private static AlipayClient client = null;static {client = new DefaultAlipayClient(ORDER_URL,APPID,ICU_PRIVATE_KEY,"JSON","utf-8",ALIPAY_PUBLICKEY,AlipayConstants.SIGN_TYPE_RSA2);}/*** 获取支付二维码* @param clieid* @param proid* @param itemid* @param visitid* @param lang* @throws Exception* @author Mr G*/public void getQrcode(String clieid,String proid,String visitid,String itemid,String lang) throws Exception{JSONObject busobj = new JSONObject();busobj.put("clieid", clieid);busobj.put("proid", proid);busobj.put("visitid", visitid);PayOrderSubmit neworder = payOrderSubmitService.createOrder(clieid,itemid,busobj.toString(),lang,PayConst.PAYTYPE_ALI_SAOMAPAY);Map<String,Object> para = new HashMap<>();para.put("out_trade_no",neworder.getPayid());para.put("subject",neworder.getExpenote());//订单标题double paymoney = neworder.getPaymoney()/100d;para.put("total_amount",String.valueOf(paymoney));//订单金额 单位元// 卖家支付宝账号ID，用于支持一个签约账号下支持打款到不同的收款账号，(打款到sellerId对应的支付宝账号)// 如果该字段为空，则默认为与支付宝签约的商户的PID，也就是appid对应的PIDString sellerId = "";para.put("body","购买"+neworder.getExpenote()+paymoney+"元");//购买商品3件共20.00元";// 支付超时，定义为120分钟String timeoutExpress = "120m";//120m//允许的最晚付款时间，逾期将关闭交易。取值范围：1m～15d。m-分钟，h-小时，d-天，1c-当天（1c-当天的情况下，无论交易何时创建，都在0点关闭）。 para.put("timeout_express", timeoutExpress);para.put("operator_id","test_operator_id");//商户操作员编号para.put("store_id", clieid);//store_id商户门店编号para.put("terminal_id", visitid);//商户机具终端编号// para.put("business_params", busobj);// para.put("extend_params", busobj);// 商品明细列表，需填写购买商品详细信息，// List<GoodsDetail> goodsDetailList = new ArrayList<GoodsDetail>();// 创建一个商品信息，参数含义分别为商品id（使用国标）、名称、单价（单位为分）、数量，如果需要添加商品类别，详见GoodsDetail// GoodsDetail goods1 = GoodsDetail.newInstance(outTradeNo, subject, 1, 1);// 创建好一个商品后添加至商品明细列表// goodsDetailList.add(goods1);AlipayTradePrecreateRequest request = new AlipayTradePrecreateRequest();request.setBizContent(JsonUtil.objToJson(para));request.setNotifyUrl(NOTIFYURL);AlipayTradePrecreateResponse response = client.execute(request);String body = response.getBody();log.debug("ali qrcode result:"+body);JSONObject jsonbody = JSONObject.parseObject(body);JSONObject tradeResp = jsonbody.getJSONObject("alipay_trade_precreate_response");String code = tradeResp.getString("code");if("10000".equals(code)) {String code_url = tradeResp.getString("qr_code");log.debug("ali-code_url="+code_url);String base64 = QrcodeUtil.generateBase64Img(code_url,LOGOPATH);//根据业务需要可以把base64直接扔给前台src//TODOif(!b) {log.error("支付宝推送二维码失败：[clieid:{},proid：{},itemid:{},visitid:{}]",clieid,proid,itemid,visitid);}}else {log.error("支付宝获取二维码失败：{},[clieid:{},proid:{},itemid:{},visitid:{}]",tradeResp.getString("sub_msg"),clieid,proid,itemid,visitid);}}
在回调接口里想着在预下单时设置几个业务上的id值，然后再回调接口里使用，结果sdk里没有找到，后来干脆再数据库里查询了一下。有知道的伙伴可以留言说下。
5、用户扫码后使用支付宝支付完，还需编写回调接口。如下；
@SuppressWarnings("unused")public void payNotify() throws Exception {Map<String, String> notifyMap = notifyMap();boolean checkV1 = AlipaySignature.rsaCheckV1(notifyMap, ALIPAY_PUBLICKEY, "utf-8" ,AlipayConstants.SIGN_TYPE_RSA2);String replymsg="";if(checkV1) {//获取订单号String out_trade_no = notifyMap.get("out_trade_no");String buyer_logon_id = notifyMap.get("buyer_logon_id");//lov***@String total_amount = notifyMap.get("total_amount");String seller_id = notifyMap.get("seller_id");String app_id = notifyMap.get("app_id");PayOrderSubmit submit = payOrderSubmitService.getOrderByPayid(out_trade_no);double paymoney = submit.getPaymoney()/100d;String ordernote = submit.getOrdernote();JSONObject noteobj = JSONObject.parseObject(ordernote);String clieid = noteobj.getString("clieid");String proid = noteobj.getString("proid");String visitid = noteobj.getString("visitid");if(submit!=null) {String trade_status = notifyMap.get("trade_status");if("TRADE_SUCCESS".equals(trade_status)) {if(total_amount.equals(String.valueOf(paymoney)) && PID.equals(seller_id)&& APPID.equals(app_id)) {//校验数据准确性replymsg=NOTIFY_SUCCESS;log.info("支付宝支付成功：clieid:{},proid:{},visitid:{},订单号：{}",clieid,proid,visitid,out_trade_no);//TODO log}else {log.error("本条通知是异常通知：[appid:{},pid:{},支付金额：{},订单号:{}]",app_id,seller_id,total_amount,out_trade_no);}}}else {replymsg = NOTIFY_FAIL;log.error("支付宝通知-未获取到相应订单，[订单号：{}]",out_trade_no);}}else {replymsg=NOTIFY_FAIL;log.error("支付宝通知验签失败。");}ContextUtil.getResponse().getWriter().write(replymsg);}@SuppressWarnings("rawtypes")private Map<String,String> notifyMap() {HttpServletRequest req = ContextUtil.getRequest();Map<String,String> para = new HashMap<>();Enumeration names = req.getParameterNames();System.out.println("notifymap-----------------------------------");while(names.hasMoreElements()) {String k = (String) names.nextElement();para.put(k, req.getParameter(k));System.out.println(k+" = "+req.getParameter(k));}return para;}
6:后记：官方给的demo是在sdk的基础上又封装了一层，看的我眼花，所以就没采用demo写法。
https://docs./399/106843/
https://docs./api_1/alipay.trade.precreate
