String merId = req.getParameter("merId");

              String orderId = req.getParameter("orderId");

              String txnTime = req.getParameter("txnTime");

              String token = req.getParameter("token");

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

              /***银联全渠道系统，产品参数，除了encoding自行选择外其他不需修改***/

              contentData.put("version", DemoBase.version);                  //版本号

              contentData.put("signMethod", SDKConfig.getConfig().getSignMethod()); //签名方法

              contentData.put("signMethod", "01");                           //签名方法 目前只支持01-RSA方式证书加密

              contentData.put("txnType", "74");                              //交易类型 74-解除标记

              contentData.put("txnSubType", "01");                           //交易子类型 01-解除标记

              contentData.put("bizType", "000902");                          //业务类型 token支付

              contentData.put("channelType", "07");                          //渠道类型07-PC

              /***商户接入参数***/

              contentData.put("merId", merId);                                         //商户号码（本商户号码仅做为测试调通交易使用，该商户号配置了需要对敏感信息加密）测试时请改成自己申请的商户号，【自己注册的测试777开头的商户号不支持代收产品】

              contentData.put("accessType", "0");                            //接入类型，商户接入固定填0，不需修改  

              contentData.put("orderId", orderId);                                //商户订单号，8-40位数字字母，不能含“-”或“_”，可以自行定制规则  

              contentData.put("txnTime", txnTime);                                        //订单发送时间，格式为YYYYMMDDhhmmss，必须取当前时间，否则会报txnTime无效

              //token号（从前台开通的后台通知中获取或者后台开通的返回报文中获取）

              contentData.put("tokenPayData", "{token="+token+"&trId=62000000001}");

              /**对请求参数进行签名并发送http post请求，接收同步应答报文**/

              Map<String, String> reqData = AcpService.sign(contentData,DemoBase.encoding);                 //报文中certId,signature的值是在signData方法中获取并自动赋值的，只要证书配置正确即可。

              String requestBackUrl = SDKConfig.getConfig().getBackRequestUrl();                    //交易请求url从配置文件读取对应属性文件acp_sdk.properties中的 acpsdk.backTransUrl

              Map<String, String> rspData = AcpService.post(reqData,requestBackUrl,DemoBase.encoding); //发送请求报文并接受同步应答（默认连接超时时间30秒，读取返回结果超时时间30秒）;这里调用signData之后，调用submitUrl之前不能对submitFromData中的键值对做任何修改，如果修改会导致验签不通过

              /**对应答码的处理，请根据您的业务逻辑来编写程序,以下应答码处理逻辑仅供参考------------->**/

              //应答码规范参考open.unionpay.com帮助中心 下载  产品接口规范  《平台接入接口规范-第5部分-附录》

              if(!rspData.isEmpty()){

                     if(AcpService.validate(rspData, DemoBase.encoding)){

                            LogUtil.writeLog("验证签名成功");

                            String respCode = rspData.get("respCode") ;

                            if(("00").equals(respCode)){

                                   //成功

                                   //TODO

                            }else{

                                   //其他应答码为失败请排查原因或做失败处理

                                   //TODO

                            }

                     }else{

                            LogUtil.writeErrorLog("验证签名失败");

                            //TODO 检查验证签名失败的原因

                     }

              }else{

                     //未返回正确的http状态

                     LogUtil.writeErrorLog("未获取到返回报文或返回http状态码非200");

              }

              String reqMessage = DemoBase.genHtmlResult(reqData);

              String rspMessage = DemoBase.genHtmlResult(rspData);

              resp.getWriter().write("请求报文:<br/>"+reqMessage+"<br/>" + "应答报文:</br>"+rspMessage+"");

LogUtil.writeLog("BackRcvResponse接收后台通知开始");

              String encoding = req.getParameter(SDKConstants.param_encoding);

              // 获取银联通知服务器发送的后台通知参数

              Map<String, String> reqParam = getAllRequestParam(req);

              LogUtil.printRequestLog(reqParam);

              Map<String, String> valideData = null;

              if (null != reqParam && !reqParam.isEmpty()) {

                     Iterator<Entry<String, String>> it = reqParam.entrySet().iterator();

                     valideData = new HashMap<String, String>(reqParam.size());

                     while (it.hasNext()) {

                            Entry<String, String> e = it.next();

                            String key = (String) e.getKey();

                            String value = (String) e.getValue();

                            valideData.put(key, value);

                     }

              }

              //重要！验证签名前不要修改reqParam中的键值对的内容，否则会验签不过

              if (!AcpService.validate(valideData, encoding)) {

                     LogUtil.writeLog("验证签名结果[失败].");

                     //验签失败，需解决验签问题

              } else {

                     LogUtil.writeLog("验证签名结果[成功].");

                     //交易成功，更新商户订单状态

                     String orderId =valideData.get("orderId"); //获取后台通知的数据，其他字段也可用类似方式获取

                     String customerInfo = valideData.get("customerInfo");

                     if(null!=customerInfo){

                           Map<String,String>  customerInfoMap = AcpService.parseCustomerInfo(customerInfo, "UTF-8");

                            LogUtil.writeLog("customerInfoMap明文: "+ customerInfoMap);

                     }

                     String accNo = valideData.get("accNo");

                     //如果配置了敏感信息加密证书，可以用以下方法解密

                     if(null!=accNo){

                            accNo = AcpService.decryptData(accNo, "UTF-8");

                            LogUtil.writeLog("accNo明文: "+ accNo);

                     }

                     String respCode = valideData.get("respCode");

                     //判断respCode=00、A6后，对涉及资金类的交易，请再发起查询接口查询，确定交易成功后更新数据库。

              }

              LogUtil.writeLog("BackRcvResponse接收后台通知结束");

              //返回给银联服务器http 200状态码

              resp.getWriter().print("ok");