文檔：https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=9_1

JSAPI下單

必傳參數(shù)：

nonce_str方法：

/**
* 獲取32位隨機(jī)字符串
* @return
*/
public static String getNonceStr() {
    Random random = new Random();
    return MD5Util.md5(String.valueOf(random.nextInt(10000)));
}

sign生成方法：

/**
* 微信支付sign簽名 --> 參數(shù)按ascii排序，key=value& 形式拼接，最后拼接上api_key，md5加密轉(zhuǎn)大寫
* @param parameters 除了sign以外的請(qǐng)求參數(shù)
* @param api_key    商戶api key
* @return
*/
public static String createSign(SortedMap<Object, Object> parameters,String api_key) {
    StringBuffer sb = new StringBuffer();
    Set<Map.Entry<Object, Object>> es = parameters.entrySet();
    Iterator<Map.Entry<Object, Object>> it = es.iterator();
    while (it.hasNext()) {
        Map.Entry<Object, Object> entry = (Map.Entry<Object, Object>) it.next();
        String k = (String) entry.getKey();
        Object v = entry.getValue();
        /** 如果參數(shù)為key或者sign，則不參與加密簽名 */
        if (null != v && !"".equals(v) && !"sign".equals(k) && !"key".equals(k)) {
            sb.append(k + "=" + v + "&");
        }
    }
    /** 支付密鑰必須參與加密，放在字符串最后面 */
    sb.append("key=" + api_key);
    /** 記得最后一定要轉(zhuǎn)換為大寫 */
    String sign = MD5Util.md5(sb.toString()).toUpperCase();
    return sign;
}

paySign生成方法

/**
* paySign生成方法 --> 參數(shù)按ascii排序，key=value& 形式拼接，最后拼接上api_key，md5加密轉(zhuǎn)大寫
* @param parameters 參數(shù)包括appId、timeStamp、nonceStr、package、signType
* @param api_key    商戶api key
* @return
*/
public static String getPaySign(SortedMap<Object, Object> resultParams){
    StringBuilder sb = new StringBuilder();
    for(Map.Entry entry : resultParams.entrySet()){
        sb.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
    }
    sb.append("key=").append(MCH_KEY);
    return MD5Util.md5(sb.toString()).toUpperCase();
}

jsapi下單方法

/**
* jsapi方法 --> 將參數(shù)以xml格式post
* @param openId openId
* @param money  金額
* @param ip 小程序端ip
* @return 返回小程序支付需要的參數(shù)
*/
public static WechatPayModel wechatPay(String openId, int money, String ip){
    SortedMap<Object, Object> parameters = new TreeMap<Object, Object>();
    parameters.put("appid", appid);
    parameters.put("mch_id", MCH_ID);
    parameters.put("openid", openId);
    parameters.put("nonce_str", getNonceStr());
    parameters.put("body", "智能柜支付");
    parameters.put("out_trade_no", createBillNo());
    parameters.put("total_fee", money);
    parameters.put("spbill_create_ip", ip);
    parameters.put("notify_url", "http://test.chinasuperbox.com/notifyUrl");
    parameters.put("trade_type", "JSAPI");
    String sign = createSign(parameters, MCH_KEY);
    parameters.put("sign", sign);
    String requestXML = XmlUtil.getRequestXml(parameters);
    Map<String,String> resultMap = payPost(wechatPayUrl, requestXML);
    WechatPayModel wechatPayModel = new WechatPayModel();
    if( resultMap.get("return_code").equals("SUCCESS") && resultMap.get("result_code").equals("SUCCESS") ){
        log.info("支付預(yù)請(qǐng)求成功");
        String prepay_id = resultMap.get("prepay_id");
        String nonce_str = resultMap.get("nonce_str");
        long timeStamp = System.currentTimeMillis()/1000;

        SortedMap<Object, Object> resultParams = new TreeMap<Object, Object>();
        resultParams.put("appId", appid);
        resultParams.put("timeStamp", timeStamp);
        resultParams.put("nonceStr", nonce_str);
        resultParams.put("package", "prepay_id="+prepay_id);
        resultParams.put("signType", "MD5");
        String paySign = getPaySign(resultParams);
        wechatPayModel.setPaySign(paySign);

        wechatPayModel.setAppId(appid);
        wechatPayModel.setNonceStr(nonce_str);
        wechatPayModel.setPackageStr("prepay_id="+prepay_id);
        wechatPayModel.setSignType("MD5");
        wechatPayModel.setTimeStamp(timeStamp);
        wechatPayModel.setMsg("支付預(yù)請(qǐng)求成功");
        return wechatPayModel;
    }else{
        if( resultMap.containsKey("err_code_des") ){
            wechatPayModel.setMsg(resultMap.get("err_code_des"));
        }else{
            wechatPayModel.setMsg(resultMap.get("return_msg"));
        }
        log.info("支付預(yù)請(qǐng)求失敗,  return_msg = {}, err_code_des = {}", resultMap.get("return_msg"), resultMap.get("err_code_des"));
        return wechatPayModel;
    }
}

工具類：

/**
* post方法，將返回的xml解析成map返回
* @param requestUrl 請(qǐng)求地址
* @param requestXML 請(qǐng)求xml字符串
* @return 返回map
*/
public static Map<String,String> payPost(String requestUrl, String requestXML){
    CloseableHttpClient httpclient = HttpClients.custom().build();
    Map<String,String> result = new HashMap<String,String>();
    HttpPost httpPost = new HttpPost(requestUrl);
    StringEntity reqEntity  = new StringEntity(requestXML, "utf-8");
    // 設(shè)置content type類型
    reqEntity.setContentType("application/x-www-form-urlencoded");
    httpPost.setEntity(reqEntity);
    try{
        CloseableHttpResponse response = httpclient.execute(httpPost);
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            // 從request中取得輸入流
            InputStream inputStream = entity.getContent();
            // 讀取輸入流
            SAXReader reader = new SAXReader();
            Document document = reader.read(inputStream);
            // 得到xml根元素
            Element root = document.getRootElement();
            // 得到根元素的所有子節(jié)點(diǎn)
            List<Element> elementList = root.elements();
            // 遍歷所有子節(jié)點(diǎn)
            for (Element e : elementList) {
                result.put(e.getName(), e.getText());
            }
        }
        return result;
    }catch (Exception e){
        e.printStackTrace();
        return null;
    }
}

/**
 * 將請(qǐng)求參數(shù)轉(zhuǎn)換為xml格式的string
 * @param parameters
 * @return
 */
public static String getRequestXml(SortedMap<Object, Object> parameters) {
    StringBuffer sb = new StringBuffer();
    sb.append("<xml>");
    Set<Map.Entry<Object, Object>> es = parameters.entrySet();
    Iterator<Map.Entry<Object, Object>> it = es.iterator();
    while (it.hasNext()) {
        Map.Entry<Object, Object> entry = (Map.Entry<Object, Object>) it.next();
        String k = (String) entry.getKey();
        String v = entry.getValue() + "";
        if ("attach".equalsIgnoreCase(k) || "body".equalsIgnoreCase(k) || "sign".equalsIgnoreCase(k)) {
            sb.append("<" + k + ">" + "<![CDATA[" + v + "]]></" + k + ">");
        } else {
            sb.append("<" + k + ">" + v + "</" + k + ">");
        }
    }
    sb.append("</xml>");
    return sb.toString();
}

回調(diào)xml

<?xml version="1.0" encoding="utf-8"?>
<xml>
  <appid><![CDATA[wx303cbfa214a64a4c]]></appid>
  <bank_type><![CDATA[OTHERS]]></bank_type>
  <cash_fee><![CDATA[1]]></cash_fee>
  <fee_type><![CDATA[CNY]]></fee_type>
  <is_subscribe><![CDATA[N]]></is_subscribe>
  <mch_id><![CDATA[1536185011]]></mch_id>
  <nonce_str><![CDATA[bb57db42f77807a9c5823bd8c2d9aaef]]></nonce_str>
  <openid><![CDATA[o_W745D0ptmzIyj7kmykJqciJPYU]]></openid>
  <out_trade_no><![CDATA[075500305202132034782700473]]></out_trade_no>
  <result_code><![CDATA[SUCCESS]]></result_code>
  <return_code><![CDATA[SUCCESS]]></return_code>
  <sign><![CDATA[4C8B3F62B4212F84BC7C830858D5BFFF]]></sign>
  <time_end><![CDATA[20210603093212]]></time_end>
  <total_fee>1</total_fee>
  <trade_type><![CDATA[JSAPI]]></trade_type>
  <transaction_id><![CDATA[4200001039202106031250761263]]></transaction_id>
</xml>

回調(diào)方法

/**
 * 回調(diào)方法 -- 注意接收字符串為xml字符串，返回格式為xml字符串
 * @param parameters
 * @return
 */
@PostMapping("/notifyUrl")
public String notifyUrl(HttpServletRequest request) {
    log.info("into notifyUrl");
    try {
        //微信返回的請(qǐng)求體
        String body = NetUtil.getRequestBody(request);
        Map<String, String> xmlMap = XmlUtil.xmlToMap(body);
        //業(yè)務(wù)邏輯處理
                payConsumService.paySuccess(xmlMap);

    } catch (Exception e) {
        e.printStackTrace();
    }
    return "<xml>"
            +"<return_code>SUCCESS</return_code>"
            +"<return_msg>OK</return_msg>"
            +"</xml>";
}