AWS签名4: Java和Crypto-JS不前进

Question

我正在使用java做一些AWS签名头的帖子。签名过程如下

    private String calculateSignature(String stringToSign) {
        try {
                byte[] signatureKey = getSignatureKey(secretAccessKey, currentDate, regionName, serviceName);
                byte[] signature = HmacSHA256(stringToSign, signatureKey);
                String strHexSignature = bytesToHex(signature);
                return strHexSignature;
            } catch (Exception ex) {
                ex.printStackTrace();
            }
            return null;
    }

    private byte[] HmacSHA256(String data, byte[] key) throws Exception {
        String algorithm = "HmacSHA256";
        Mac mac = Mac.getInstance(algorithm);
        mac.init(new SecretKeySpec(key, algorithm));
        return mac.doFinal(data.getBytes("UTF8"));
    }

    private byte[] getSignatureKey(String key, String date, String regionName, String serviceName) throws Exception {
        byte[] kSecret = ("AWS4" + key).getBytes("UTF8");
        byte[] kDate = HmacSHA256(date, kSecret);
        byte[] kRegion = HmacSHA256(regionName, kDate);
        byte[] kService = HmacSHA256(serviceName, kRegion);
        byte[] kSigning = HmacSHA256(aws4Request, kService);
        return kSigning;
    }

    private String bytesToHex(byte[] bytes) {
        final StringBuilder hexString = new StringBuilder();
        for(byte b : bytes)
            hexString.append(String.format("%02x", b));
        return hexString.toString().toLowerCase().trim();
    }

但是，当我使用此签名发送时，它与服务器计算的签名不匹配。服务器端采用PHP编写，使用Crypto-JS进行签名计算。我比较了两个字符串需要签名和规范的请求在Java和PHP之间。它们是匹配的。

我已经检查了空间，命令和其他特征。但却找不到原因。Java HmacSHA256和crypto-js HmacSHA256有什么不同？还是bytesToHex方法出了什么问题？

规范请求的Java输出

POST
/

content-length:667
content-type:application/json
host:host.name.com
x-amz-date:20171205T012629Z
x-amz-target:_20141201.XXXXXXX

content-length;content-type;host;x-amz-date;x-amz-target
c5b31b699700e6debe4548836a723f89b73ffcef6570e1bed4c534c0f247dc26

PHP返回：

POST
/

content-length:667
content-type:application/json
host:host.name.com
x-amz-date:20171205T012629Z
x-amz-target:_20141201.XXXXXXX

content-length;content-type;host;x-amz-date;x-amz-target
c5b31b699700e6debe4548836a723f89b73ffcef6570e1bed4c534c0f247dc26

任何帮助或任何想法都将不胜感激。