Map> to JSON, & Pretty Print

Question

I'm trying to make my dataset correspond to this example:

var family = [{
    "name" : "Jason",
    "age" : "24",
    "gender" : "male"
},
{
    "name" : "Kyle",
    "age" : "21",
    "gender" : "male"
}];

I have a Map<String, HashSet<String>> of Names and unique alpha-numeric values correponding to specific entities to which those names could refer, let's call these entry items "IDs".

So for instance, Fyodor Mikhailovich Dostoyevsky would perhaps be related to the ID Q626, because that's a very specific reference, there aren't many widely known figures with that name. Whereas, Bush might be attached to G027, Q290, and Q118, referencing perhaps the man, the beer, and the shrub, in no particular order.

It looks like this (the real one is much bigger):

[Rao=[Q7293658, , Q7293657, Q12953055, Q3531237, Q4178159, Q1138810, Q579515, Q3365064, Q7293664, Q1133815], Hani Durzy=[], Louise=[, Q1660645, Q130413, Q3215140, Q152779, Q233203, Q7871343, Q232402, Q82547, Q286488, Q156723, Q3263649, Q456386, Q233192, Q14714149, Q12125864, Q57669, Q168667, Q141410, Q166028], Reyna=[Q7573462, Q2892895, Q363257, Q151944, Q3740321, Q2857439, Q1453358, Q7319529, Q733716, Q16151941, Q7159448, Q5484172, Q6074271, Q1753185, Q7319532, Q5171205, Q3183869, Q1818527, Q251862, Q3840414, Q5271282, Q5606181]]

Using Jackson I tried like this:

Map<String, HashSet<String>>  map = q_valMap;
mapper.writeValue(new File("JSON_Output/user.json"), map);

But this seems wrong, as my output was all jumbled together, i.e.

{"Rao":["Q7293658","","Q7293657","Q12953055","Q3531237","Q4178159","Q1138810","Q579515","Q3365064","Q7293664","Q1133815"],"Hani Durzy":[""],"Louise":["","Q1660645","Q130413","Q3215140","Q152779","Q233203","Q7871343","Q232402","Q82547","Q286488","Q156723","Q3263649","Q456386","Q233192","Q14714149","Q12125864","Q57669","Q168667","Q141410","Q166028"],"Reyna":["Q7573462","Q2892895","Q363257","Q151944","Q3740321","Q2857439","Q1453358","Q7319529","Q733716","Q16151941","Q7159448","Q5484172","Q6074271","Q1753185","Q7319532","Q5171205","Q3183869","Q1818527","Q251862","Q3840414","Q5271282","Q5606181"]}

Do I just have to populate this JSON object iteratively?

Like the example up top, I think it should look something like this, though what follows is only a pseudocodish characterization, which is to say, not exactly this but something similar:

{
    key: "Rao"
    value:  ["Q7293658","","Q7293657","Q12953055","Q3531237","Q4178159","Q1138810","Q579515","Q3365064","Q7293664","Q1133815"]

    key: "Hani Durzy"
    value: [""]

    key: "Louise"
    value: ["","Q1660645","Q130413","Q3215140","Q152779","Q233203","Q7871343","Q232402","Q82547","Q286488","Q156723","Q3263649","Q456386","Q233192","Q14714149","Q12125864","Q57669","Q168667","Q141410","Q166028"]

    key: "Reyna"
    value: ["Q7573462","Q2892895","Q363257","Q151944","Q3740321","Q2857439","Q1453358","Q7319529","Q733716","Q16151941","Q7159448","Q5484172","Q6074271","Q1753185","Q7319532","Q5171205","Q3183869","Q1818527","Q251862","Q3840414","Q5271282","Q5606181"]
}

is that not right?

UPDATE

public class JsonMapFileExample 
{
    public static void map(Map<String, HashSet<String>> q_valMap ) 
    {

        ObjectMapper mapper = new ObjectMapper();


        ArrayNode array = mapper.createArrayNode();
        for ( Entry entry: q_valMap.entrySet() ) 
        {
          ObjectNode node = mapper.createObjectNode()
              .put("name", entry.getKey())
              .put("ids", entry.getValue());
          array.add(node);
        }
        mapper.writeValue("/home/matthias/Workbench/SUTD/nytimes_corpus/wdtk-parent/wdtk-examples/JSON_Output/user.json", array);

    }
}


class MyEntity
{
    private String name;
    Set<String> value; // use names that you want in the result JSON

    //constructors
    public MyEntity() 
    {

    }
    public MyEntity(String name) 
    {
        this.name = name;
    }

    //getters
    public String getName() 
    {
        return this.name;
    }
    public Set<String>  getValue() 
    {
        return this.value;
    }

    //setters
    public void setName(String name) 
    {
        this.name = name;
    }
    public void setValue(Set<String> value) 
    {
        this.value = value;
    }
}

@iced thank you for checking this out. what do you think of the answer i just wrote? — smatthewenglish, Apr 25 '15 at 09:02

hsluo · Accepted Answer · 2015-04-25T07:14:02.967

2

You could manually set the key names, something like:

ArrayNode array = mapper.createArrayNode();
for (Entry entry: yourMap.entries()) {
  ObjectNode node = mapper.createObjectNode()
      .put("name", entry.key())
      .putPOJO("ids", entry.value());
  array.add(node);
}
mapper.writeValue(file, array);

Alternatively, you could create a class for your data

class MyEntity {
  String name;
  Set<String> ids; // use names that you want in the JSON result
  // getters, setters if necessary
}

Transform your data map into a list of MyEntity, then use Jackson ObjectMapper to create JSON like mapper.writeValue(file, listOfMyEntities), the output would be like

[
  {
    "name": "some name here",
    "ids": ["id1", "id2", ...]  
  }
  // more elements here
]

edited Apr 25 '15 at 07:14

answered Apr 24 '15 at 05:43

hsluo

1,652
15
20

would the output of that look like what i just added on the bottom of the question? does this use jackson? – smatthewenglish Apr 24 '15 at 05:51
what do you mean by malformed – smatthewenglish Apr 24 '15 at 05:59
You would have 4 `key` and 4 `value` in one JSON object, which is not good – hsluo Apr 24 '15 at 06:00
but under `Storing JSON Data in Arrays` in [this site](http://www.copterlabs.com/blog/json-what-it-is-how-it-works-how-to-use-it/), that's what I'm going for. but I don't know how to make it. – smatthewenglish Apr 24 '15 at 06:02
Please find my updates and see if it's what you're looking for – hsluo Apr 24 '15 at 06:17
seems createArrayNode is undefined for `Map>` – smatthewenglish Apr 24 '15 at 06:22
under **UPDATE** I added what I've been doing. it doesn't like that `put` there's some error about I should cast it to a json node. I made getters and setters for that class, how could i make a list of those? – smatthewenglish Apr 24 '15 at 06:34
If you ever read the documentation or looked at the API popped up in your IDE, you will find how to add an object – hsluo Apr 24 '15 at 06:57
do you have a reference to the documentation i need to look at? i've been trying to find it – smatthewenglish Apr 24 '15 at 10:28

score 0 · Answer 2 · answered Apr 25 '15 at 09:01

how about this:

        String name_list_file = "/home/matthias/Workbench/SUTD/nytimes_corpus/NYTimesCorpus/2005/01/02/test/people_test.txt";

        String single_name;

        try (   
                // read in the original file, list of names, w/e
                InputStream stream_for_name_list_file = new FileInputStream( name_list_file );
                InputStreamReader stream_reader = new InputStreamReader( stream_for_name_list_file , Charset.forName("UTF-8"));
                BufferedReader line_reader = new BufferedReader( stream_reader );
            ) 
        {
            while (( single_name = line_reader.readLine() ) != null) 
            {
                //replace this by a URL encoder
                //String associated_alias = single_name.replace(' ', '+');
                String associated_alias = URLEncoder.encode( single_name , "UTF-8");

                String platonic_key = single_name;
                System.out.println("now processing: " + platonic_key);

                Wikidata_Q_Reader.getQ( platonic_key, associated_alias );
            }
        }

        //print the struc
        Wikidata_Q_Reader.print_data();


    }

Map> to JSON, & Pretty Print

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