POST request JSON Parser Java

Question

I've read this post on how to do a POST request in Java. I don't understand how I can implement this in a JSON parser. This is what I tried so far:

public class JSONParser {
    private String read(BufferedReader bufferedReader) throws IOException {
        //Creates new StringBuilder to avoid escaping chars
        StringBuilder stringBuilder = new StringBuilder();
        //Gets the currentLine
        String currentLine;
        while((currentLine = bufferedReader.readLine()) !=null ){
            //Adds the currentLine to the stringBuild if the currentLine is not null
            stringBuilder.append(currentLine);
        }
        //Returns the StringBuilder is String format
        return stringBuilder.toString();
    }

    public JSONObject readJsonFromUrl(String JSONurl) throws IOException, JSONException {
        InputStream url = new URL(JSONurl).openStream();
        try {
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(url));
            String jsonText = read(bufferedReader);
            JSONObject json = new JSONObject(jsonText);
            return json;
        } finally {
            url.close();
        }
    }

    public void printJSON() throws IOException, JSONException {
        JSONObject json = readJsonFromUrl("http://grwn.ddns.net:1337/locations");
        System.out.print(json);

        //for (Integer i = 0; i < json.getJSONArray("damage_or_theft_car").length(); i++) {
        //    System.out.println(json.getJSONArray("damage_or_theft_car")
        //.getJSONObject(i).get("hood_id"));
        //}
    }
}

When I run this code with a link which doesn't require a POST request it all works fine but when I run this code on a link which DOES require a POST request I get the following error:

Exception in thread "main" java.io.FileNotFoundException: http://grwn.ddns.net:1337/locations
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1872)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
    at java.net.URL.openStream(URL.java:1045)
    at com.company.JSONParser.readJsonFromUrl(JSONParser.java:30)
    at com.company.JSONParser.printJSON(JSONParser.java:42)
    at com.company.Main.main(Main.java:33)

Could someone help me out or point me in the right direction?

The reason you are getting FileNotFoundE is probably because the response code is 404. Have you tried some other post request that does not result in 404 response ? — semywow, Jun 28 '17 at 09:09
@semywow It's not sending a POST request because I don't know how — Sander bakker, Jun 28 '17 at 10:04

score 1 · Accepted Answer · answered Jun 28 '17 at 10:24

1

I think you need to specify that you want to make a POST request after you open the connection, maybe try something like this.

public JSONObject readJsonFromUrl(String JSONurl) throws IOException, JSONException {
    URL url = new URL(JSONurl);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("POST");
    conn.setRequestProprtry("Content-type", "application/JSON");
    try {
        BufferedReader bufferedReader = new BufferedReader(conn. getInputStream());
        String jsonText = read(bufferedReader);
        JSONObject json = new JSONObject(jsonText);
        return json;
    } finally {
        url.close();
    }
}

answered Jun 28 '17 at 10:24

gugge

918
1
11
17

BufferReader cannot be applied to java.io.inputstream – Sander bakker Jun 28 '17 at 10:26
You could make a inputStreamReader instance and then a BufferReader like you did. I can't test it since I'm on a phone atm. – gugge Jun 28 '17 at 10:52
I've fixed it already. I will edit your answer in a second and accept it! – Sander bakker Jun 28 '17 at 10:54

score 0 · Answer 2 · answered Jun 28 '17 at 09:36

Possible causes for this issue might be one of the following; 1) Nothing to read/fetch from url 2) Check proxy settings, might be something configured on proxy for access to above url 3) Hostname mapping missing on your host

Some of the ways to verify this manually are as follows; 1) Try to access url from the web browser with proxy setting, see if you can get the desired raw json 2) Try to access url from the web browser without proxy setting, see if you can get the desired raw json 3) If step 1) or Step2) is successful, try same from your java code

POST request JSON Parser Java

2 Answers2