Parsing JSON response(includes a list) in java

Question

I did a http client and I'm getting a response. I am using a JSONObject to parse the data and when I execute the code below it prints out all of the JSON just fine

HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        if(entity!=null){
            try(InputStream instream = entity.getContent()) {
                String responseString = readInputStream(instream);
                JSONObject job = new JSONObject(responseString);
                statusLabel.setText("Command Result: " + job.toString());

Here is the readInputSream function:

static 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();
}

If I change it from job.toString() to:

statusLabel.setText("Command Result: " + job.get("result"));

it prints a 1 which is correct, it works all the way up to my_list. I'm not sure how to parse the list. I put a snippet of the response below. Ive tried "my_list", "my_list[]", my_list[0]" which none have worked. I get JSONObject "blank" not found

{"result":1,  "ver":1,"total":2,"catch":true,"my_list":[{"id":3,"mid":0,"format":3,"user":4,"property":1,"type":0,"title":"hello","start":146,"end":1464,"hid":3,"bid":1,"reason":1,"time":0,"creator":"1","hello":0,"my":0,"year":"0","ggg":614,"name":"","ch":"0","attr":0,"type":1,"vtype":1,"tm_log": {"fr":4,"action":0,"vr":"82","started":1,"av_ended":2,"tr":1}}

Why are you trying to read it by yourself, instead of using something ready like: docs.oracle.com/javaee/7/api/javax/json/… — uylmz
– uylmz, Commented Jun 2, 2016 at 16:12

The Head Rush · Accepted Answer · 2016-06-02 16:08:08Z

2

The element you trying to retrieve is parsed into a JSONArray, not a JSONObject. Try:

JSONArray my_list = job.getJSONArray("my_list");

answered Jun 2, 2016 at 16:08

The Head Rush

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1 Comment

B.minnick Over a year ago

Thank you, now I am able to get the data. But when I do my_list.get(0) It prints out the data in random order. Is there a way to say only get "id" from my_list?

Michael Gantman · Accepted Answer · 2016-06-02 16:20:54Z

Assuming that you are using json parser project JSON-java to parse your JSON you need to retrieve a JSONArray instance - this is how arrays are storred in JSONObject. so do the following: JSONArray my_list = job.getJSONArray("my_list"); and then use methods of JSONArray class to access your array. The Javadoc to JSON-java package can be found here: http://stleary.github.io/JSON-java/index.html. Also note that JSON-java is very simple and easy to use JSON parser project but it is not very efficient for any serious project. Common recommendation for commercial use is Jackson JSON Processor which is one of the fastest and powerful JSON parsers. Here are some links to read about it: https://github.com/FasterXML/jackson, http://wiki.fasterxml.com/JacksonHome

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