/**
     * 微信支付回调
     * @param params
     * @return
     */
    @RequestMapping("/wechatPayCallback")
    public JSONObject wechatPayCallback(@RequestBody Map<String, Object> params) {
 
        log.info("WechatPayCallback...");
 
        JSONObject resourceJson = JSONUtil.parseObj(params.get("resource"));
        log.info(resourceJson.toString());
        try {
            String decrypt = WechatUtil.decryptToString(resourceJson.getStr("associated_data").getBytes(), resourceJson.getStr("nonce").getBytes(), resourceJson.getStr("ciphertext"));
            log.info(decrypt);
 
            JSONObject decryptJson = JSONUtil.parseObj(decrypt);
            String out_trade_no = decryptJson.getStr("out_trade_no");
            // out_trade_no就是创建订单时的编号，下面就是写自己的支付逻辑
        } catch (Exception e) {
            log.info(e.getMessage());
            e.printStackTrace();
        }
 
        return JSONUtil.createObj()
                .set("code", "SUCCESS")
                .set("message", "成功");
    }
/**
     * 解密
     * @param associatedData
     * @param nonce
     * @param ciphertext
     * @return
     * @throws GeneralSecurityException
     * @throws IOException
     */
    public static String decryptToString(byte[] associatedData, byte[] nonce, String ciphertext)
            throws GeneralSecurityException, IOException {
        try {
            Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 
            SecretKeySpec key = new SecretKeySpec(API_V3_KEY.getBytes(), "AES");
            GCMParameterSpec spec = new GCMParameterSpec(128, nonce);
 
            cipher.init(Cipher.DECRYPT_MODE, key, spec);
            cipher.updateAAD(associatedData);
 
            return new String(cipher.doFinal(Base64.getDecoder().decode(ciphertext)), StandardCharsets.UTF_8);
        } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
            throw new IllegalStateException(e);
        } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
            throw new IllegalArgumentException(e);
        }
    }