Unity | About WWW POST request using JSON request format

Recent access error correction API Baidu AI text , requires structural body JSON format to describe the contents of a particular request. Access request as follows:

•  code show as below:

private class Body 
{
   public string text = "";
}


IEnumerator ErrorCorrection()
    {
        string apiKey = "自己的apiKey";

        string appSecret = "自己的appSecret";

        WWW www = new WWW("https://aip.baidubce.com/oauth/2.0/token?grant_type=client_credentials&client_id=" + apiKey + "&client_secret=" + appSecret);

        yield return www;

        if (www.isDone)
        {
            if (www.error == null)
            {
                JsonData res = JsonMapper.ToObject(www.text);

                if (res["access_token"] != null)
                {
                    access_token = res["access_token"].ToString();

                    Debug.Log(access_token);

                    //请求参数body
                    Body body = new Body();

                    body.text = "百度是一家人工只能公司";

                    string requestdata = JsonMapper.ToJson(body);

                    //不能这样:
                    //string requestdata = "text=百度是一家人工只能公司";

                    byte[] postBytes = Encoding.UTF8.GetBytes(requestdata);

                    //header
                    Dictionary<string, string> header = new Dictionary<string, string>();

                    header.Add("Content-Type", "application/json");

                    www = new WWW("https://aip.baidubce.com/rpc/2.0/nlp/v1/ecnet?charset=UTF-8&access_token=" + access_token, postBytes, header);

                    yield return www;

                    if (www.isDone)
                    {
                        if (www.error == null)
                        {
                            Debug.Log(www.text);
                        }
                    }
                    else
                    {
                        Debug.Log(www.error);
                    }
                }
            }
            else
            {
                Debug.Log(www.error);
            }
        }

    }

•  Request results were as follows:

{
"log_id":4559397244907480534,
"item":{
   "vec_fragment":[
   {
      "ori_frag":"只能",
      "begin_pos":21,
      "correct_frag":"智能",
      "end_pos":27
   }],
  "score":0.961834,
  "correct_query":"百度是一家人工智能公司"
 },
"text":"百度是一家人工只能公司"
}