src/main/java/com/qingstor/sdk/upload/UploadManager.java
private void sign(RequestHandler requestHandler) throws QSException {
        if (callBack != null) {
            String signed = callBack.onSignature(requestHandler.getStringToSignature());
            if (!QSStringUtil.isEmpty(signed))
                requestHandler.setSignature(callBack.onAccessKey(), signed);
            String correctTime = callBack.onCorrectTime(requestHandler.getStringToSignature());
            if (correctTime != null && correctTime.trim().length() > 0)
                requestHandler.getBuilder().setHeader(QSConstant.HEADER_PARAM_KEY_DATE, correctTime);
        }
    }
private void sign(RequestHandler requestHandler) throws QSException {
        if (callBack != null) {
            String signed = callBack.onSignature(requestHandler.getStringToSignature());
            if (!QSStringUtil.isEmpty(signed))
                requestHandler.setSignature(callBack.onAccessKey(), signed);
            String correctTime = callBack.onCorrectTime(requestHandler.getStringToSignature());
            if (correctTime != null && correctTime.trim().length() > 0)
                requestHandler.getBuilder().setHeader(QSConstant.HEADER_PARAM_KEY_DATE, correctTime);
        }
    }
When sending a request will call this method to sign with server.
@param requestHandler handler of the request.
@throws QSException exception