用QT编写的文字识别程序，代码如下：

void RequestDialog::startRequest()
{
QFile file("d:/word.jpg");
if(!file.open(QFile::ReadOnly))
{
return ;
}
QByteArray fileBuff = file.readAll();
file.close();

QUrl url("https://aip.baidubce.com/rest/2.0/ocr/v1/general");
QUrlQuery urlQuery;
urlQuery.addQueryItem("access_token", "XXX_XXXXXXXX");
url.setQuery(urlQuery);
QNetworkRequest request;
request.setRawHeader("Content-Type", "application/x-www-form-urlencoded");
request.setUrl(url);
QByteArray postArray;
postArray.append("image=");
postArray.append(fileBuff.toPercentEncoding());//按照要求UrlEncode

reply = qnam.post(request, postArray);
//...
}

总是返回image transcode error，貌似UrlEncode不对？望高人指点！