Json request gives error

Question

i´am trying to send a JSON string over http via android and iam trying to validate it via http://www.jsontest.com/#validate .

I get the response:

"error": "A JSONObject text must begin with '{' at 1 [character 2 line 1]"

Here is my code:

public class Nethelper
{
public JSONObject uploadToServer() throws IOException, JSONException
{
    String query = "http://validate.jsontest.com/?json=";

    URL url = new URL(query);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setConnectTimeout(5000);
    conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
    conn.setDoOutput(true);
    conn.setDoInput(true);
    conn.setRequestMethod("POST");

    JSONObject jsonObject = new JSONObject();
    jsonObject.put("key", "value");
    String json = jsonObject.toString();
    OutputStream os = conn.getOutputStream();

    OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");

    osw.write(json);
    osw.flush();
    osw.close();

    // read the response
    InputStream in = new BufferedInputStream(conn.getInputStream());

    String result = convertStreamToString(in);

    JSONObject jsonObjectres = new JSONObject(result);


    in.close();
    conn.disconnect();

    return jsonObjectres;
}

private String convertStreamToString(InputStream is) {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();

    String line = null;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line).append('\n');
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return sb.toString();
}

Any idea what could be wrong? I have tried several different ways but all gives the same error.

Unrelated to your problem, still noteworthy: You should specify the response encoding too. — Tobias, Jan 30 '17 at 18:45

score 1 · Answer 1 · edited May 23 '17 at 12:33

Yea, you need to properly post your json string with POST var of json:

String query = "http://validate.jsontest.com/";
// create the connection
URL url = new URL(query);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty( "charset", "utf-8");

// set up the data to send ("json=foobar")
JSONObject jsonObject = new JSONObject();
jsonObject.put("key", "value");
String urlParameters  = "json="+ jsonObject.toString();
byte[] postData       = urlParameters.getBytes("UTF-8");
int    postDataLength = postData.length;
conn.setRequestProperty( "Content-Length", Integer.toString( postDataLength ));

// write the postdata to the connection.
OutputStream osw = conn.getOutputStream();
osw.write(postData);
osw.flush();
osw.close();

// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());

String result = convertStreamToString(in);

JSONObject jsonObjectres = new JSONObject(result);


in.close();
conn.disconnect();

other helpful info here : Java - sending HTTP parameters via POST method easily

Json request gives error

1 Answers1