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

                   //版本号

                   contentData.put("version", DemoBase.version);    

                   //字符集编码 可以使用UTF-8,GBK两种方式

                   contentData.put("encoding", DemoBase.encoding_UTF8);         

                   //签名方法  01:RSA证书方式  11：支持散列方式验证SHA-256 12：支持散列方式验证SM3

                   contentData.put("signMethod", SDKConfig.getConfig().getSignMethod());

                   //交易类型 95-银联加密公钥更新查询

                   contentData.put("txnType", "95"); 

                   //交易子类型  默认00

                   contentData.put("txnSubType", "00");  

                   //业务类型  默认

                   contentData.put("bizType", "000000"); 

                   //渠道类型

                   contentData.put("channelType", "07");                                                   

                   //01：敏感信息加密公钥(只有01可用)

                   contentData.put("certType", "01");

                   //商户号码（商户号码777290058110097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("merId", "777290058110048"); 

                   //接入类型，商户接入固定填0，不需修改

                   contentData.put("accessType", "0"); 

                   //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("orderId", DemoBase.getOrderId());       

                   //订单发送时间，格式为YYYYMMDDhhmmss，必须取当前时间，否则会报txnTime无效     

                   contentData.put("txnTime", DemoBase.getCurrentTime());                              

                   //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。

                   Map<String, String> reqData = AcpService.sign(contentData,DemoBase.encoding_UTF8);        

                   //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

                   String requestBackUrl = SDKConfig.getConfig().getBackRequestUrl();          

                   //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

                   Map<String, String> rspData = AcpService.post(reqData,requestBackUrl,DemoBase.encoding_UTF8);

if(!rspData.isEmpty()){

                            if(AcpService.validate(rspData, DemoBase.encoding_UTF8)){

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

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

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

                                               int resultCode = AcpService.updateEncryptCert(rspData,"UTF-8");

                                               if (resultCode == 1) {

                                                        LogUtil.writeLog("加密公钥更新成功");

                                              } else if (resultCode == 0) {

                                                        LogUtil.writeLog("加密公钥无更新");

                                               } else {

                                                        LogUtil.writeLog("加密公钥更新失败");

                                               }

                                     }else{

                                               //其他应答码为失败请排查原因

                                               //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");

                   }

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].");

 //【注：为了安全验签成功才应该写商户的成功处理逻辑】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 respCode = valideData.get("respCode");

 }

 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");