Facebook 消息器不发送消息

Question

I would like to show my codes but I do not know why my facebook has not got the message. Thank you very much for help

    HttpURLConnection myConnection = (HttpURLConnection) ((new URL("https://graph.facebook.com/v2.6/me/messages?access_token=the_access_token").openConnection()));
    myConnection.setDoOutput(true);
    myConnection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
    myConnection.setRequestProperty("Accept", "application/json");      
    myConnection.setRequestMethod("POST");
    myConnection.connect(); 
  JSONObject myTest = new JSONObject();

        try {
            JSONObject recipient = new JSONObject();
            recipient.put("id", "martinxxxxxwang");         
            myTest.put("recipient", recipient);
            JSONObject message = new JSONObject();
            message.put("text", "888");         
            myTest.put("message", message);     
            response.getWriter().append(myTest.toString());             

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }       
        OutputStream os = myConnection.getOutputStream();
        os.write(myTest.toString().getBytes("UTF-8"));
        os.close();

By the way, the content of "myTest" is {"recipient":{"id":"martinxxxxxwang"},"message":{"text":"888"}}. And if i try
"graph.facebook.com/v2.6/me/messages?access_token=token"‌​;, I was told ""error": { "message": "(#100) The parameter user_id is required", "type": "OAuthException", "code": 100, "fbtrace_id": "FEv3jq/ahEq" } }"

Answer 1

The problem is in the recipient Id, if any field of the json not is OK in many times return this error. In your case is the recipient id.