使用HttpClient类发送JSON数据提示UTF8错误

使用HttpClient类发送JSON数据到指定地址，该地址带用户名和密码验证，所以我在header加上以下代码：

    m_pFile->AddRequestHeaders("Accept: */*,application/json");
    m_pFile->AddRequestHeaders("Accept-Charset:UTF-8");
    m_pFile->AddRequestHeaders("Accept-Language: zh-cn;q=0.8,en;q=0.6,ja;q=0.4");
    m_pFile->AddRequestHeaders("Content-Type:application/json; charset=UTF-8");
    m_pFile->AddRequestHeaders("Authorization:Basic YKaa");

POST发送一段JSON数据后提示如下错误

{"error":"Format 'UTF8: Type cannot be determined' invalid or incompatible with argument"}

请教一下，这会是哪里出了问题？

参考一下：

String parma = "{\"name\": \"hah\"}";
                url = new URL("url");
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setDoOutput(true);
                connection.setDoInput(true);
                connection.setUseCaches(false);
                connection.setRequestMethod("POST");
                connection.setRequestProperty("Connection", "Keep-Alive");
                connection.setRequestProperty("Content-Length", String.valueOf(parma.length()));
                connection.setRequestProperty("Content-Type","application/json; charset=UTF-8");
                connection.setRequestProperty("accept","application/json");

                OutputStream out = connection.getOutputStream();
                out.write(parma.getBytes());
                out.flush();
                out.close();