Parsing a JSON String to get all instances of fields

veryangryman · 01-06-2017 9:25pm #1

Hi

This REST query gives among other stuff, the created_at dates. I want to parse the output to get all the dates and then sort them. The lines in question i need to parse look like

"created_at": "2013-01-08T20:11:48Z",

Query here

https://api.github.com/search/repositories?q=language:Java

Is there an efficient way of doing this?

punk_one82 · 02-06-2017 1:00am

veryangryman wrote: »

Is there an efficient way of doing this?

Yes, parsing JSON is usually fairly simple. What language are you coding in? You're looking for the created_at key in an array of "items". If you're using Java, then maybe look at using org.json

awec · 02-06-2017 9:53am

That's a date in ISO 8601 format. I don't know java but I'd be surprised if there isn't a way to parse this format.

veryangryman · 02-06-2017 9:53am

punk_one82 wrote: »

Yes, parsing JSON is usually fairly simple. What language are you coding in? You're looking for the created_at key in an array of "items". If you're using Java, then maybe look at using org.json

Java yes

lawred2 · 02-06-2017 9:54am

veryangryman wrote: »

Hi

This REST query gives among other stuff, the created_at dates. I want to parse the output to get all the dates and then sort them. The lines in question i need to parse look like

"created_at": "2013-01-08T20:11:48Z",

Query here

https://api.github.com/search/repositories?q=language:Java

Is there an efficient way of doing this?

just use an off the shelf json parser

veryangryman · 02-06-2017 10:01am

Trying the recommended one from above...

URI uri = null;
        JSONTokener tokener = null;
        try {
            uri = new URI("https://api.github.com/search/repositories?q=language:Java");
            URL url = uri.toURL();
            InputStream inputStream = url.openStream();
            tokener = new JSONTokener(inputStream.toString());
            JSONObject root = new JSONObject(tokener);
        } catch (Exception e) {
            e.printStackTrace();
        }

But hits exception

org.json.JSONException: A JSONObject text must begin with '{' at character 1
	at org.json.JSONTokener.syntaxError(JSONTokener.java:410)
	at org.json.JSONObject.<init>(JSONObject.java:179)
	at Assignment1.processRestResponse(Assignment1.java:48)
	at Assignment1.main(Assignment1.java:108)

Anything obvious i need to change?

02-06-2017 11:06am

inputStream.toString() does not do what you think it does. Just pass inputStream to the constructor

veryangryman · 02-06-2017 11:11am

28064212 wrote: »

inputStream.toString() does not do what you think it does. Just pass inputStream to the constructor

tokener = new JSONTokener(inputStream);

This is not accepted. Cannot resolve constructor

02-06-2017 11:17am

veryangryman wrote: »

tokener = new JSONTokener(inputStream);

This is not accepted. Cannot resolve constructor

Ah, I was looking at a different JSONTokener. In that case you need to handle the conversion of the InputStream to a String yourself e.g. https://stackoverflow.com/questions/309424/read-convert-an-inputstream-to-a-string

veryangryman · 02-06-2017 11:24am

28064212 wrote: »

Ah, I was looking at a different JSONTokener. In that case you need to handle the conversion of the InputStream to a String yourself e.g. https://stackoverflow.com/questions/309424/read-convert-an-inputstream-to-a-string

Ok nearly there...

Now the Charset name isnt recognised though. Cannot resolve symbol

try (Reader reader = new BufferedReader(
                    new InputStreamReader(
                            inputStream, Charset.forName(StandardCharsets.[COLOR="Red"]UTF8.name[/COLOR]()))))
            {
                int c = 0;
                while ((c = reader.read()) != -1) {
                    textBuilder.append((char) c);
                }
            }catch(Exception e){}

            Scanner s = new Scanner(inputStream).useDelimiter("\\A");
            String result = s.hasNext() ? s.next() : "";

            tokener = new JSONTokener(result);
            JSONObject root = new JSONObject(tokener);

02-06-2017 11:31am

Depends on your Java version, but this might work [no .name()]:

StandardCharsets.UTF_8

Parsing a JSON String to get all instances of fields

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