How to convert an Array List of objects to Json

Question

I have an ArrayList which I want to transform into a JSON array of objects. How can I transform it?

Array is of type Kunde:

public class Kunde {
    private String knr;
    private String name1;
    private String name2;
    private String anrede;
    private String strasse;
    private String plz;
    private String ort;
    private String erfdat;
    private String telefon;
    private String fax;
    private String handy;
    private String lastbes;
    private String email;
    private String land;

for each member variable there is a getter and a setter.

I store it like this:

   List<Kunde> Kunden = new ArrayList<Kunde>();

My JSON should look like this:

   { 
     "kunden": [
       {"name1": "hans", "name2": "peter"}, 
       {...} 
     ]
   }

Is it really a duplicate if it's Play Framework specific? – Karol Dowbecki Mar 17 '18 at 17:32 — Karol Dowbecki, Mar 17 '18 at 17:32

Karol Dowbecki · Accepted Answer · 2018-03-17T17:29:37.490

1

Play comes with play-json module which can do it. You might have to create a wrapping class to output the kunden root node:

public class Kunden {
  private List<Kunde> kunden;
  // getter and setter
}

Kunden root = new Kunden();
kunden.setKunden(...);

JsonNode rootNode = Json.toJson(root);
ObjectMapper mapper = new ObjectMapper(); 
String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(node);

Note that ObjectMapper is used to pretty print.

See the official Play Framework 2.6.X docs: Mapping Java objects to JSON.

edited Mar 17 '18 at 17:29

answered Mar 17 '18 at 17:17

Karol Dowbecki

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works absolute fine! – Felix Mar 17 '18 at 17:25

score -2 · Answer 2 · answered Mar 17 '18 at 17:17

-2

Try to do something like this

ArrayList<Kundle> list = new ArrayList<Kundle>();
    list.add("yo");
    list.add("yo");
    JSONArray jsArray = new JSONArray(list);

answered Mar 17 '18 at 17:17

Xay

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How to convert an Array List of objects to Json

2 Answers2