一、下载证书并导入到系统

微信支付接口中，涉及资金回滚的接口会使用到商户证书，包括退款、撤销接口。商家在申请微信支付成功后，可以按照以下路径下载：微信商户平台(pay.weixin.qq.com)-->账户设置-->API安全-->证书下载。

下载的时候需要手机验证及登录密码。下载后找到apiclient_cert.p12这个证书，双击导入，导入的时候提示输入密码，这个密码就是商户ID,且必须是在自己的商户平台下载的证书。否则会出现密码错误的提示：

导入正确的提示：

二、编写代码

首先初始化退款接口中的请求参数，如微信订单号transaction_id（和商户订单号只需要知道一个）、订单金额total_fee等；其次调用MobiMessage中的RefundResData2xml方法解析成需要的类型；最后调用RefundRequest类的httpsRequest方法触发请求。

/** * 处理退款请求 * @param request * @return * @throws Exception */ @RequestMapping("/refund") @ResponseBody public JsonApi refund(HttpServletRequest request) throws Exception { //获得当前目录 String path = request.getSession().getServletContext().getRealPath("/"); LogUtils.trace(path); Date now = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss");//可以方便地修改日期格式 String outRefundNo = "NO" + dateFormat.format( now ); //获得退款的传入参数 String transactionID = "4008202001201609012791655620"; String outTradeNo = "20160901141024"; Integer totalFee = 1; Integer refundFee = totalFee; RefundReqData refundReqData = new RefundReqData(transactionID,outTradeNo,outRefundNo,totalFee,refundFee); String info = MobiMessage.RefundReqData2xml(refundReqData).replaceAll("__", "_"); LogUtils.trace(info); try { RefundRequest refundRequest = new RefundRequest(); String result = refundRequest.httpsRequest(WxConfigure.REFUND_API, info, path); LogUtils.trace(result); Map<String, String> getMap = MobiMessage.parseXml(new String(result.toString().getBytes(), "utf-8")); if("SUCCESS".equals(getMap.get("return_code")) && "SUCCESS".equals(getMap.get("return_msg"))){ return new JsonApi(); }else{ //返回错误描述 return new JsonApi(getMap.get("err_code_des")); } }catch(Exception e){ e.printStackTrace(); return new JsonApi(); }}

初始化退款接口需要的数据，隐藏了get和set方法。

public class RefundReqData { //每个字段具体的意思请查看API文档 private String appid = ""; private String mch_id = ""; private String nonce_str = ""; private String sign = ""; private String transaction_id = ""; private String out_trade_no = ""; private String out_refund_no = ""; private int total_fee = 0; private int refund_fee = 0; private String op_user_id = ""; /** * 请求退款服务 * @param transactionID 是微信系统为每一笔支付交易分配的订单号，通过这个订单号可以标识这笔交易，它由支付订单API支付成功时返回的数据里面获取到。建议优先使用 * @param outTradeNo 商户系统内部的订单号,transaction_id 、out_trade_no 二选一，如果同时存在优先级：transaction_id>out_trade_no * @param outRefundNo 商户系统内部的退款单号，商户系统内部唯一，同一退款单号多次请求只退一笔 * @param totalFee 订单总金额，单位为分 * @param refundFee 退款总金额，单位为分 */ public RefundReqData(String transactionID,String outTradeNo,String outRefundNo,int totalFee,int refundFee){ //微信分配的公众号ID（开通公众号之后可以获取到） setAppid(WxConfigure.AppId); //微信支付分配的商户号ID（开通公众号的微信支付功能之后可以获取到） setMch_id(WxConfigure.Mch_id); //transaction_id是微信系统为每一笔支付交易分配的订单号，通过这个订单号可以标识这笔交易，它由支付订单API支付成功时返回的数据里面获取到。 setTransaction_id(transactionID); //商户系统自己生成的唯一的订单号 setOut_trade_no(outTradeNo); setOut_refund_no(outRefundNo); setTotal_fee(totalFee); setRefund_fee(refundFee); setOp_user_id(WxConfigure.Mch_id); //随机字符串，不长于32 位 setNonce_str(StringUtil.generateRandomString(16)); //根据API给的签名规则进行签名 SortedMap<Object, Object> parameters = new TreeMap<Object, Object>(); parameters.put("appid", appid); parameters.put("mch_id", mch_id); parameters.put("nonce_str", nonce_str); parameters.put("transaction_id", transaction_id); parameters.put("out_trade_no", out_trade_no); parameters.put("out_refund_no", out_refund_no); parameters.put("total_fee", total_fee); parameters.put("refund_fee", refund_fee); parameters.put("op_user_id", op_user_id); String sign = DictionarySort.createSign(parameters); setSign(sign); //把签名数据设置到Sign这个属性中 }

MobiMessage实现json数据类型和xml数据之间的转换。

public class MobiMessage { public static Map<String,String> xml2map(HttpServletRequest request) throws IOException, DocumentException { Map<String,String> map = new HashMap<String, String>(); SAXReader reader = new SAXReader(); InputStream inputStream = request.getInputStream(); Document document = reader.read(inputStream); Element root = document.getRootElement(); List<Element> list = root.elements(); for(Element e:list){ map.put(e.getName(), e.getText()); } inputStream.close(); return map; } //订单转换成xml public static String JsApiReqData2xml(JsApiReqData jsApiReqData){ MobiMessage.xstream.alias("xml",jsApiReqData.getClass()); return MobiMessage.xstream.toXML(jsApiReqData); } public static String RefundReqData2xml(RefundReqData refundReqData){ MobiMessage.xstream.alias("xml",refundReqData.getClass()); return MobiMessage.xstream.toXML(refundReqData); } public static String class2xml(Object object){ return ""; } public static Map<String, String> parseXml(String xml) throws Exception { Map<String, String> map = new HashMap<String, String>(); Document document = DocumentHelper.parseText(xml); Element root = document.getRootElement(); List<Element> elementList = root.elements(); for (Element e : elementList) map.put(e.getName(), e.getText()); return map; } //扩展xstream，使其支持CDATA块 private static XStream xstream = new XStream(new XppDriver() { public HierarchicalStreamWriter createWriter(Writer out) { return new PrettyPrintWriter(out) { // 对所有xml节点的转换都增加CDATA标记 boolean cdata = true; //@SuppressWarnings("unchecked") public void startNode(String name, Class clazz) { super.startNode(name, clazz); } protected void writeText(QuickWriter writer, String text) { if (cdata) { writer.write("<![CDATA["); writer.write(text); writer.write("]]>"); } else { writer.write(text); } } }; } }); }

RefundRequest类中initCert方法加载证书到系统中，其中证书地址如下：

public static String certLocalPath = "/WEB-INF/cert/apiclient_cert.p12";

RefundRequest类中httpsRequest方法调用微信接口，触发请求。

/** * User: rizenguo * Date: 2014/10/29 * Time: 14:36 */public class RefundRequest { //连接超时时间，默认10秒 private int socketTimeout = 10000; //传输超时时间，默认30秒 private int connectTimeout = 30000; //请求器的配置 private RequestConfig requestConfig; //HTTP请求器 private CloseableHttpClient httpClient; /** * 加载证书 * @param path * @throws IOException * @throws KeyStoreException * @throws UnrecoverableKeyException * @throws NoSuchAlgorithmException * @throws KeyManagementException */ private void initCert(String path) throws IOException, KeyStoreException, UnrecoverableKeyException, NoSuchAlgorithmException, KeyManagementException { //拼接证书的路径 path = path + WxConfigure.certLocalPath; KeyStore keyStore = KeyStore.getInstance("PKCS12"); //加载本地的证书进行https加密传输 FileInputStream instream = new FileInputStream(new File(path)); try { keyStore.load(instream, WxConfigure.Mch_id.toCharArray()); //加载证书密码，默认为商户ID } catch (CertificateException e) { e.printStackTrace(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } finally { instream.close(); } // Trust own CA and all self-signed certs SSLContext sslcontext = SSLContexts.custom() .loadKeyMaterial(keyStore, WxConfigure.Mch_id.toCharArray()) //加载证书密码，默认为商户ID .build(); // Allow TLSv1 protocol only SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory( sslcontext, new String[]{"TLSv1"}, null, SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER); httpClient = HttpClients.custom() .setSSLSocketFactory(sslsf) .build(); //根据默认超时限制初始化requestConfig requestConfig = RequestConfig.custom().setSocketTimeout(socketTimeout).setConnectTimeout(connectTimeout).build(); } /** * 通过Https往API post xml数据 * @param url API地址 * @param xmlObj 要提交的XML数据对象 * @param path 当前目录，用于加载证书 * @return * @throws IOException * @throws KeyStoreException * @throws UnrecoverableKeyException * @throws NoSuchAlgorithmException * @throws KeyManagementException */ public String httpsRequest(String url, String xmlObj, String path) throws IOException, KeyStoreException, UnrecoverableKeyException, NoSuchAlgorithmException, KeyManagementException { //加载证书 initCert(path); String result = null; HttpPost httpPost = new HttpPost(url); //得指明使用UTF-8编码，否则到API服务器XML的中文不能被成功识别 StringEntity postEntity = new StringEntity(xmlObj, "UTF-8"); httpPost.addHeader("Content-Type", "text/xml"); httpPost.setEntity(postEntity); //设置请求器的配置 httpPost.setConfig(requestConfig); try { HttpResponse response = httpClient.execute(httpPost); HttpEntity entity = response.getEntity(); result = EntityUtils.toString(entity, "UTF-8"); } catch (ConnectionPoolTimeoutException e) { LogUtils.trace("http get throw ConnectionPoolTimeoutException(wait time out)"); } catch (ConnectTimeoutException e) { LogUtils.trace("http get throw ConnectTimeoutException"); } catch (SocketTimeoutException e) { LogUtils.trace("http get throw SocketTimeoutException"); } catch (Exception e) { LogUtils.trace("http get throw Exception"); } finally { httpPost.abort(); } return result; }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。