微信公众号支付大致分为以下几步：
1.获取openID：微信公众号支付一个重要的参数就是openID，此步骤可以查阅相关文档
2.获取支付相关参数：appid：公众账号ID，mch_id：商户号，nonce_str：随机字符串，sign_type：签名类型，out_trade_no：商户订单号，total_fee：标价金额（交易金额默认为人民币交易，接口中参数支付金额单位为【分】，参数值不能带小数），spbill_create_ip：终端IP，notify_url：通知地址，trade_type：交易类型，openid：用户标识，sign：签名
TreeMap paramMap = new TreeMap();paramMap.put("appid", PaymentConst.WECHAT_APPID);//公众账号IDparamMap.put("mch_id", PaymentConst.WECHAT_MCHID);//商户号paramMap.put("nonce_str", Util.getRandomString(30, null));//随机字符串paramMap.put("sign_type", PaymentConst.WECHAT_SIGNTYPE);//签名类型//paramMap.put("body", "爱检查医疗套餐支付");//商品描述paramMap.put("body", "Melical Fee");//商品描述paramMap.put("out_trade_no", orderMain.getNumber());//商户订单号//交易金额默认为人民币交易，接口中参数支付金额单位为【分】，参数值不能带小数。paramMap.put("total_fee", (int)(orderMain.getTotalamount()*100));//标价金额paramMap.put("spbill_create_ip", Util.getIpAddr(request));//终端IPparamMap.put("notify_url", weChatNotifyUrl);//通知地址paramMap.put("trade_type", PaymentConst.WECHAT_TRADETYPE_JSAPI);//交易类型paramMap.put("openid", openid);//用户标识paramMap.put("sign",Signature.createSign("UTF-8", paramMap));//签名
3.签名算法：
public static String createSign(String characterEncoding,SortedMap<String,Object> parameters){StringBuffer sb = new StringBuffer();Set es = parameters.entrySet();Iterator it = es.iterator();while(it.hasNext()) {Map.Entry entry = (Map.Entry)it.next();String k = (String)entry.getKey();Object v = entry.getValue();if(null != v && !"".equals(v) && !"sign".equals(k) && !"key".equals(k)) {sb.append(k + "=" + v + "&");}}sb.append("key=" + PaymentConst.WECHAT_KEY);System.out.println("签名："+sb.toString());String sign =MD5.GetMD5Code(sb.toString()).toUpperCase();return sign;}
4.请求：
String response = HttpClientUtil.post(PaymentConst.wechatPayUrl,new String( XMLUtils.simpleMapToXml(paramMap).getBytes(), "UTF-8"));
5.XMLUtils.simpleMapToXml 方法：
public static String simpleMapToXml(Map<String, Object> map){ StringBuilder xmlString = new StringBuilder(); xmlString.append("<?xml version='1.0' encoding='UTF-8'?>").append(RT); xmlString.append("<xml>").append(RT); for (Map.Entry<String, Object> entry : map.entrySet()){ String key = entry.getKey(); xmlString.append("<" + key + ">" + entry.getValue() + "</" + key + ">").append(RT); } xmlString.append("</xml>").append(RT); return xmlString.toString(); }
6.返回预支付结果，二次签名
System.out.println("预支付返回结果："+response);Map<String, String> resultParams = getWechatXmlToMap(response); if (PaymentConst.WECHAT_STATUSCODE_FAIL.equals(resultParams.get("return_code"))){ throw new MessageException(resultParams.get("return_msg")); }else{ if (PaymentConst.WECHAT_STATUSCODE_FAIL.equals(resultParams.get("result_code"))){ throw new MessageException(resultParams.get("return_msg")); }else{ String prepay_id = resultParams.get("prepay_id"); TreeMap paramMap1 = new TreeMap(); paramMap1.put("appId", paramMap.get("appid"));//公众账号ID String s = String.valueOf(Util.getSecond()); paramMap1.put("timeStamp", s); paramMap1.put("nonceStr", Util.getRandomString(30, null)); paramMap1.put("package", "prepay_id="+prepay_id);//签名类型 paramMap1.put("signType", paramMap.get("sign_type"));//签名类型 paramMap1.put("sign1",Signature.createSign("UTF-8", paramMap1));//签名 LOGGER.info("最终签名:"+paramMap1.get("sign1")); //生成前台支付需要的数据 Map<String, Object> map = new HashMap<String, Object>(); map.put("appId", paramMap.get("appid")); String s1 = String.valueOf(Util.getSecond()); map.put("timeStamp", s1); map.put("nonceStr", Util.getRandomString(30, null)); map.put("package", "prepay_id="+prepay_id); map.put("signType", paramMap.get("sign_type")); map.put("paySign", paramMap1.get("sign1")); System.out.println("tttttttttttttttttttttttttttttt9999999999999tttttttttttttttttttttttttttttttttttttt"); result.setT(map); } }
7./** * @Title：getWechatXmlToMap * @Description：微信返回xml结果转为Map * @param result * @return * @throws Exception Map<String,String> 返回类型 */ private Map<String, String> getWechatXmlToMap(String result) throws Exception{ SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser parser = factory.newSAXParser(); XMLHandler xmlHandler = new XMLHandler(); parser.parse(new ByteArrayInputStream(result.getBytes("UTF-8")), xmlHandler); return xmlHandler.getParams(); }
8.授权成功回调方法
/*** @Title：weixinPayBack* @Description：支付回调(微信支付)* @param request* @return String 返回类型*/@RequestMapping(value="/weiXinPayNotify")public String weixinPayBack(HttpServletRequest request){ try { InputStream inStream = request.getInputStream(); ByteArrayOutputStream outSteam = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while ((len = inStream.read(buffer)) != -1) { outSteam.write(buffer, 0, len); } outSteam.close(); inStream.close(); String resultStr = new String(outSteam.toByteArray(),"utf-8"); System.out.println("微信支付的回调："+resultStr); Map<String, String> resultMap = getWechatXmlToMap(resultStr); String return_code = resultMap.get("return_code"); if("SUCCESS".equals(return_code)){ //检验API返回的数据里面的签名是否合法，避免数据在传输的过程中被第三方篡改 if(!Signature.checkIsSignValidFromResponseString(resultStr)){ throw new MessageException("微信回调参数签名不合法"); } String result_code = resultMap.get("result_code"); if("SUCCESS".equals(result_code)){ //支付成功的业务逻辑 //通知微信.异步确认成功.必写.不然微信会一直通知后台.八次之后就认为交易失败了. return "<xml><return_code><![CDATA[SUCCESS]]></return_code><return_msg><![CDATA[OK]]></return_msg></xml>"; } } } catch (Exception e) { LOGGER.error(e.getMessage() ,e); } return "<xml><return_code><![CDATA[FAIL]]></return_code><return_msg><![CDATA[ERROR]]></return_msg></xml>";}
9.签名错误测试方法：
https://pay.weixin.qq.com/wiki/doc/api/native.php?chapter=20_1
填入如下参数
点击生成签名：出现如下xml
复制xml:
重新选择xml校验方式
生成签名出现下面的提示，校验通过，说明签名正确
其他签名错误情况检查参数是否正确
