Parsing InputStream into Json object and getting a value

Question

The response json:

{
    "filename": "vcops-6.0.0-MPforAWS-1.1-1695068.pak",
    "links": [
        {
            "rel": "pak_information",
            "href": "https://<IP>:443/casa/upgrade/cluster/pak/MPforAWS-600/information"
        },
        {
            "rel": "pak_file_information",
            "href": "https://<IP>:443/casa/upgrade/slice/pak/MPforAWS-600/file_information"
        },
        {
            "rel": "pak_cluster_status",
            "href": "https://<IP>:443/casa/upgrade/cluster/pak/MPforAWS-600/status"
        }
    ],
    "pak_id": "MPforAWS-600"
}

I am using one helper of the framework we have. Framework returns response as "InputStream". I want to get "pak_id" from this "InputStream". I tried with inputStreamObj.toString() this does not work for me.

The method I am using is:

private String getPakId(InputStream uploadResponse) {
    String pakId = null;
    try {
        String responseString = readInputStream(uploadResponse);
        JSONObject jObj = new JSONObject(responseString);
        pakId = jObj.getString("pak_id").trim();
        Reporter.log("Pak id is=" + pakId, true);
    } catch (Exception e) {
        Reporter.log("Error in getting pak_id " + e.getMessage(), true);
    }
    return pakId;
}

and

private String readInputStream(InputStream inputStream) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(
            inputStream, "UTF-8"));
    String tmp;
    StringBuilder sb = new StringBuilder();
    while ((tmp = reader.readLine()) != null) {
        sb.append(tmp).append("\n");
    }
    if (sb.length() > 0 && sb.charAt(sb.length() - 1) == '\n') {
        sb.setLength(sb.length() - 1);
    }
    reader.close();
    return sb.toString();
}

You have to read the String from your InputStream and then parse it using JSON library. — Aleks G, Apr 14 '14 at 09:56
possible duplicate of http://stackoverflow.com/questions/6511880/how-to-parse-a-json-input-stream — Joffrey, Apr 14 '14 at 09:58
JSONObject jObj = new JSONObject(response.toString()); pakId = jObj.getString("pak_id").trim(); — Shashi Ranjan, Apr 14 '14 at 10:20
The question is duplicate. Try this solution: https://stackoverflow.com/a/47265988/1264496 — Surendra Kumar, Nov 15 '17 at 11:13

score 2 · Answer 1 · answered Apr 14 '14 at 11:31

If you look at the documentation for InputStream, you'll notice it will not promise you that toString will present you the contents of the stream.

If you're not interested in actually streaming the stream (which is reasonable if you expect the response to be small, like it appears to be the case here), it's OK to first get all the bytes from the stream, put them into a String, and then parse the String.

To get the String out of the InputStream, I'd recommend IOUtils.toString from apache commons-io.

jeojavi · Answer 2 · 2014-04-14T13:37:47.570

0

If you only want the pak_id value using only the standard library:

InputStream is = ...
String line;
StringBuilder text = new StringBuilder();
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
while((line = reader.readLine()) != null) {
    text.append(line).append(" ");
}
String pakId = text.toString().replaceAll(".*\"pak_id\": \"([^\"]+)\".*", "$1");

edited Apr 14 '14 at 13:37

answered Apr 14 '14 at 10:08

jeojavi

876
1
6
15

What I want to say, I have this response stored in "InputStream" object, and I need to retrieve "pak_id" – Shashi Ranjan Apr 14 '14 at 10:21
I updated my answer so now you can obtain the `pak_id` value directly from the `InputStream` – jeojavi Apr 14 '14 at 12:27

score -1 · Answer 3 · answered Nov 01 '17 at 16:32

-1

Well, better late than never... the following worked for me:

JSONTokener tokener = new JSONTokener(new InputStreamReader(istream));
JSONObject result;
try {
    result = new JSONObject(tokener);
} catch (JSONException e) {
    // Handle me!
}

answered Nov 01 '17 at 16:32

ender2101

1
1

Parsing InputStream into Json object and getting a value

The response json:

3 Answers3