微信支付V3（公众号支付demo）

之前没排版，看起来很难受，现在舒服多了！

准备工作

商户证书

微信支付证书

通知地址notifyUrl（必须外网可访问！）

1、组装必要参数，调用下单接口

// 自动更新微信支付证书

private static AutoUpdateCertificatesVerifier verifier;

// 商户私钥（privateKey：一串特别长的base64串）
PrivateKey merchantPrivateKey = PemUtil.loadPrivateKey(new ByteArrayInputStream(privateKey.getBytes("utf-8")));

// 使用自动更新的签名验证器，不需要传入证书
verifier = new AutoUpdateCertificatesVerifier(
      new WechatPay2Credentials(mchid, new PrivateKeySigner(mchSerialNo, merchantPrivateKey)),
      apiV3Key.getBytes("utf-8"));

// 构建httpClient
httpClient = WechatPayHttpClientBuilder.create().withMerchant(mchid, mchSerialNo, merchantPrivateKey)
      .withValidator(new WechatPay2Validator(verifier)).build();

// v3下单接口
HttpPost httpPost = new HttpPost("https://api.mch.weixin.qq.com/v3/pay/transactions/jsapi");

// 设置订单失效时间4分钟（微信要求日期格式）
long expireTime = System.currentTimeMillis()+4*60*1000;
DateFormat sf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX");
Date date = new Date(expireTime);
String format = sf.format(date);

// 组装订单json串
String data = "{\r\n" +
    "    \"time_expire\": \""+ format +"\",\r\n" +
    "    \"amount\": {\r\n" +
    "        \"total\": "+ amount +",\r\n" +
    "        \"currency\": \"CNY\"\r\n" +
    "    },\r\n" +
    "    \"mchid\": \""+ mchid +"\",\r\n" +
    "    \"description\": \""+ orgiValue +"，数量：" + numI + "客服微信：qzy345371236"+"\",\r\n" +
    "    \"notify_url\": \""+ WeChatPayConstants.notifyUrl +"\",\r\n" +
    "    \"payer\": {\r\n" +
    "        \"openid\": \""+ openid +"\"\r\n" +
    "    },\r\n" +
    "    \"out_trade_no\": \""+ outTradeNo +"\",\r\n" +
    "    \"appid\": \""+ appid +"\",\r\n" +
    "    \"attach\": \""+ orgi +"\",\r\n" +
    "    \"scene_info\": {\r\n" +
    "        \"payer_client_ip\": \""+ createIp +"\"\r\n" +
    "    }\r\n" +
    "}";

// 订单json串
StringEntity reqEntity = new StringEntity(data, ContentType.create("application/json", "utf-8"));
httpPost.setEntity(reqEntity);
httpPost.addHeader("Accept", "application/json");
// 微信支付证书序列号
httpPost.addHeader("Wechatpay-Serial", wechatPaySerial);

// 执行下单
CloseableHttpResponse response1 = httpClient.execute(httpPost);
try {
    HttpEntity entity = response1.getEntity();
    String s = EntityUtils.toString(entity);
    JSONObject parseObject = JSONObject.parseObject(s);
    String prepayId = parseObject.getString("prepay_id");
    EntityUtils.consume(entity);
    long now = System.currentTimeMillis()/1000;
    String nonceStr = SignUtil.generateNonceStr();
    prepayId = "prepay_id="+prepayId;
    String token = SignUtil.getToken(appid, prepayId, now, nonceStr);
    // 组装唤起微信支付
    mmap.put("appId", appid);
    mmap.put("timeStamp", now);
    mmap.put("nonceStr", nonceStr);
    mmap.put("packageStr", prepayId);
    mmap.put("paySign", token);
    mmap.put("outTradeNo", outTradeNo);
    if (!StringUtils.isBlank(returnUrl)) {
        mmap.put("returnUrl", returnUrl);// 付款成功后返回的地址
    }
}
finally {
    response1.close();
}
return "pay";// 唤起微信支付的页面路径

2、唤起支付页面直接用微信给的demo，改改路径参数直接用就行！

3、支付回调

boolean successFlag = true;
HttpServletRequest request;
// 获取回调报文
request.setCharacterEncoding("UTF-8");
int size = request.getContentLength();
InputStream is = request.getInputStream();
byte[] reqBodyBytes = readBytes(is, size);
String resBody = new String(reqBodyBytes);

//回调响应头必要数据，没有这些参数说明回调不对
String headerTimestamp = request.getHeader("Wechatpay-Timestamp");
String headerNonce = request.getHeader("Wechatpay-Nonce");
String headerSerial = request.getHeader("Wechatpay-Serial");
String headerSignature = request.getHeader("Wechatpay-Signature");
if(headerTimestamp==null || headerNonce==null || headerSerial==null || headerSignature==null) {
    logger.error("回调响应头参数有误！");
    failReason = "回调响应头参数有误！";
    successFlag = false;
}else {
	// 组装验证回调微信支付签名必要参数
	PrivateKey merchantPrivateKey = PemUtil.loadPrivateKey(new ByteArrayInputStream(privateKey.getBytes("utf-8")));
	verifier = new AutoUpdateCertificatesVerifier(
	        new WechatPay2Credentials(mchid, new PrivateKeySigner(mchSerialNo, merchantPrivateKey)),
	        apiV3Key.getBytes("utf-8"));
	String message = headerTimestamp + "\n" + headerNonce + "\n" + resBody + "\n";
	// 执行验证回调微信支付签名
	boolean verify = verifier.verify(headerSerial, message.getBytes(StandardCharsets.UTF_8), headerSignature);
	if(!verify) {
	    logger.error("回调验证签名失败！");
	    failReason = "回调验证签名失败！";
	    successFlag = false;
	}
	//验证头部携带的序列号是否和付款时候一致，不一致说明有可能被串改，不执行后续操作
	if(!wechatPaySerial.equals(headerSerial)) {
	    logger.error("回调的微信支付证书序列号与请求的不一致！");
	    failReason = "回调的微信支付证书序列号与请求的不一致！";
	    successFlag = false;
	}
}

if(successFlag) {
   	//解析回调主体
    JSONObject po = JSON.parseObject(resBody);
    JSONObject jo = po.getJSONObject("resource");
    String ciphertext = jo.getString("ciphertext");
    String nonce = jo.getString("nonce");
    String associatedData = jo.getString("associated_data");
    //解密密文
    String jsonData = "";
    AesUtil decryptor = new AesUtil(apiV3Key.getBytes(StandardCharsets.UTF_8));
    if(associatedData != null) {
        jsonData = decryptor.decryptToString(associatedData.getBytes(StandardCharsets.UTF_8), nonce.getBytes(StandardCharsets.UTF_8), ciphertext);
    }else {
        jsonData = decryptor.decryptToString(null, nonce.getBytes(StandardCharsets.UTF_8), ciphertext);
    }
    //解密完之后的资源数据
    HashMap<String, Object> map = JSON.parseObject(jsonData, HashMap.class);
    //商户订单号
    String outTradeNo = (String) map.get("out_trade_no");
    String tradeState = (String) map.get("trade_state");
    
    if ("SUCCESS".equals(tradeState)) {
        logger.info("success,测试回调验签成功");
        // 1.查询订单，修改订单状态
    }
}
// 返回响应
response.setContentType("text/html;charset=UTF-8");
response.setCharacterEncoding("UTF-8");
response.getOutputStream().write(响应code.getBytes());
response.flushBuffer();

//回调结束

// readBytes工具
public static final byte[] readBytes(InputStream is, int contentLen) {
    if (contentLen > 0) {
        int readLen = 0;
        int readLengthThisTime = 0;
        byte[] message = new byte[contentLen];
        try {
            while (readLen != contentLen) {
                readLengthThisTime = is.read(message, readLen, contentLen - readLen);
                if (readLengthThisTime == -1) {// Should not happen.
                    break;
                }
                readLen += readLengthThisTime;
            }
            return message;
        } catch (IOException e) {
        }
    }
    return new byte[] {};
}

注意：商户证书和微信支付证书一定要分清楚！