method does not support a request body: GET/POST

Question

Cannot send GET or POST reply request to server, getting following error

java.net.ProtocolException: method does not support a request body: GET/POST

What I try to do is to read site content and calculate a simple math equation which is being generated in there and send answer back to server. Cannot figure out why it throws exception and how to fix my issue.

class HTTPRequest extends AsyncTask<String, String, String> {
    String field1;
    String field2;

    public HTTPRequest (String arg1, String arg2) {
        field1 = arg1;
        field2 = arg2;
    }

    @Override
    protected String doInBackground(String... urls) {
        try {
            URL url = new URL(urls[0]);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setDoOutput(true);
            conn.setChunkedStreamingMode(0);

            InputStream in = new BufferedInputStream(conn.getInputStream());
            String html = readStream(in);

            Pattern pattern = Pattern.compile("\\t+(\\d+) ([+-]) (\\d+) = <input name=\"answer\"");
            Matcher matcher = pattern.matcher(html);

            Integer res = null;
            if (matcher.find()) {
                if (matcher.group(2).equals("-"))
                    res = Integer.parseInt(matcher.group(1)) - Integer.parseInt(matcher.group(3));
                else if (matcher.group(2).equals("+"))
                    res = Integer.parseInt(matcher.group(1)) + Integer.parseInt(matcher.group(3));
            }

            //Result is calculated! sending POST request
            if (res != null) {
                Log.d("RESULT", Integer.toString(res));
                String data = URLEncoder.encode("field1", "UTF-8")
                        + "=" + URLEncoder.encode(field1, "UTF-8");
                data += "&" + URLEncoder.encode("field2", "UTF-8") + "="
                        + URLEncoder.encode(field2, "UTF-8");
                data += "&" + URLEncoder.encode("answer", "UTF-8") + "="
                        + URLEncoder.encode(Integer.toString(res), "UTF-8");

                //ERR ON THIS LINE
                DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
                wr.writeBytes(data);
                wr.flush();
                wr.close();

                BufferedReader in1 = new BufferedReader(
                        new InputStreamReader(conn.getInputStream()));
                String inputLine;
                StringBuffer response = new StringBuffer();

                while ((inputLine = in1.readLine()) != null) {
                    response.append(inputLine);
                }
                in.close();
                Log.d("RESPONE",respone);

            }
            conn.disconnect();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    private String readStream(InputStream is) throws IOException {
        StringBuilder sb = new StringBuilder();
        BufferedReader r = new BufferedReader(new InputStreamReader(is),1000);
        for (String line = r.readLine(); line != null; line =r.readLine()){
            sb.append(line);
            sb.append(System.getProperty("line.separator"));
        }
        is.close();
        return sb.toString();
    }
}

traceback:

System.err: java.net.ProtocolException: method does not support a request body: POST
System.err:     at libcore.net.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:201)
System.err:     at com.streak.myapp.HTTPRequest.doInBackground(HTTPRequest.java:73)
System.err:     at com.streak.myapp.HTTPRequest.doInBackground(HTTPRequest.java:24)
System.err:     at android.os.AsyncTask$2.call(AsyncTask.java:287)
System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
System.err:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
System.err:     at java.lang.Thread.run(Thread.java:841)

add `conn.setDoInput(true);` and run it again ? Could you also post the complete stacktrace of the exception ? — Blackbelt, Jan 06 '16 at 10:58
are you writing the backend too? Is it possible that the backend does not support post requests? — Blackbelt, Jan 06 '16 at 11:07
@Blackbelt no i don't, but it does since i've done the same on python and it worked — PYPL, Jan 06 '16 at 11:08
@Blackbelt `DataOutputStream wr = new DataOutputStream(conn.getOutputStream());` — PYPL, Jan 06 '16 at 11:15
@Blackbelt my device is 5.0.2 but its also happning on android emulator on api level 18 — PYPL, Jan 06 '16 at 11:36
@Blackbelt first im reading the html to get math equation and then sending answer back to server and reading the server's respone — PYPL, Jan 06 '16 at 11:42
what happens if you send a fix string. Without reading the first time. Do you get the same exception ? — Blackbelt, Jan 06 '16 at 11:43
@Blackbelt no it does not throw any exception... thats strange — PYPL, Jan 06 '16 at 11:47
no it is not imo. I would have expected the same behaviour. What happens if you use the old code (reading, writing, reading), and remove `is.close();` from readStream? — Blackbelt, Jan 06 '16 at 11:55

score 2 · Accepted Answer · answered Jan 07 '16 at 14:56

Solved my issue by adding

CookieHandler.setDefault( new CookieManager( null, CookiePolicy.ACCEPT_ALL ) );

and creating new connection to the same host.

@Override
protected Void doInBackground(String... urls) {
    CookieHandler.setDefault( new CookieManager( null, CookiePolicy.ACCEPT_ALL ) );
    String data="";
    try {
        URL url = new URL(urls[0]);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        InputStream in = new BufferedInputStream(conn.getInputStream());
        String html = readStream(in);

        Pattern pattern = Pattern.compile("\\t+(\\d+) ([+-]) (\\d+) = <input name=\"answer\"");
        Matcher matcher = pattern.matcher(html);

        Integer res = null;
        if (matcher.find()) {
            if (matcher.group(2).equals("-"))
                res = Integer.parseInt(matcher.group(1)) - Integer.parseInt(matcher.group(3));
            else if (matcher.group(2).equals("+"))
                res = Integer.parseInt(matcher.group(1)) + Integer.parseInt(matcher.group(3));
        }

        if (res != null) {
            data += URLEncoder.encode("field1", "UTF-8")
                    + "=" + URLEncoder.encode(field1, "UTF-8");
            data += "&" + URLEncoder.encode("field2", "UTF-8") + "="
                    + URLEncoder.encode(field2, "UTF-8");
            data += "&" + URLEncoder.encode("answer", "UTF-8") + "="
                    + URLEncoder.encode(Integer.toString(res), "UTF-8");
        }
        conn.disconnect();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        URL url = new URL(urls[0]);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("charset", "utf-8");
        conn.setDoOutput(true); //ENABLE POST REQUEST
        DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
        wr.writeBytes(data);
        wr.flush(); wr.close();
        InputStream in = new BufferedInputStream(conn.getInputStream());
        data = readStream(in);
        conn.disconnect();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    // Now data==final html respond
    Document doc = Jsoup.parse(data);
    Elements allAnchorTags = doc.select("tr");
    return null;
}

method does not support a request body: GET/POST

1 Answers1