How to generate Json with Java

Question

I am working on an application where i have to generate a json like this:

[
  {"title":"Culture","start":"Salary","end":"Work"},
  {"title":"Work","start":"Salary","end":"Work"}
]

But my code generates json like this:

{{"name":"Culture"},[{"name":"Salary"},{"name":"Work"}],}

My code:

public class ParseJson {



public static class EntryListContainer {

    public List<Entry> children = new ArrayList<Entry>();
    public Entry name;

}

public static class Entry {

    private String name;

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

}



public static void main(String[] args) {
    EntryListContainer elc1 = new EntryListContainer();
    elc1.name = new Entry("Culture");
    elc1.children.add(new Entry("Salary"));
    elc1.children.add(new Entry("Work"));




    ArrayList<EntryListContainer> al = new ArrayList<EntryListContainer>();
    Gson g = new Gson();

    al.add(elc1);


    StringBuilder sb = new StringBuilder("{");
    for (EntryListContainer elc : al) {

        sb.append(g.toJson(elc.name));
        sb.append(",");
        sb.append(g.toJson(elc.children));
        sb.append(",");
    }

    String partialJson = sb.toString();

    if (al.size() > 1) {
        int c = partialJson.lastIndexOf(",");
        partialJson = partialJson.substring(0, c);
    }

    String finalJson = partialJson + "}";
    System.out.println(finalJson);

    }

}

Can anyone help me to generate this json in my required format ?? please thanks in advance

Create a class that represents your data, then use Gson to stringify the class — user5283155
– user5283155, Commented Sep 8, 2015 at 14:45
Welcome to Stack Overflow! I added formatting to your required json schema, Also I rewrote a couple of lines to correct gramma and make your question concise. Good luck — Ilya Khaprov
– Ilya Khaprov, Commented Sep 8, 2015 at 14:51
Hint: for a start you need fields called title, start and end ... — Stephen C
– Stephen C, Commented Sep 8, 2015 at 14:51
btw I also suggest you to use library for rendering json. It might be trickier than you think. — Ilya Khaprov
– Ilya Khaprov, Commented Sep 8, 2015 at 14:52

user5283155 · Accepted Answer · 2015-09-08 14:54:03Z

5

Try this

public class Entry {
    public String title;
    public String start;
    public String end;
}

And in another part of your code

private ArrayList<Entry> entries = new ArrayList<>();

// Fill the entries...

String the_json = new Gson().toJson(entries);

answered Sep 8, 2015 at 14:54

user5283155

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Comments

biology.info · Accepted Answer · 2015-09-08 15:10:27Z

1

1) First Create your POJO

public class MyJSONObject {

    private String title;
    private String start;
    private String end;

    //getter and setter methods

   [...]

    @Override
    public String toString() {

    }

}

2) Use com.google.code.gson library

public static void main(String[] args) {

 {
    ArrayList<MyJSONObject> myJSONArray = new ArrayList<>();

    MyJSONObject obj = new MyJSONObject();
    obj.setTitle="Culture";
    obj.set[...]

    myJSONArray.add(obj);

    Gson gson = new Gson();

    // convert java object to JSON format,
    // and returned as JSON formatted string
    String json = gson.toJson(myJSONArray);

    System.out.println(json);
}

Output : [{"title":"Culture","start":"Salary","end":"Work"}, ...]

edited Sep 8, 2015 at 15:10

answered Sep 8, 2015 at 14:54

biology.info

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Comments

The F · Accepted Answer · 2015-09-08 15:46:05Z

0

I recommend you to use some JSON Java API, like Gson. It's very simple to generate a string json from a POJO object or to create a POJO object from a string json.

The code for generating a string json from a POJO object is like this:

Gson gson = new Gson();
String stringJson = gson.toJson(somePojoObject);

The code for creating a POJO object from a string json is like this:

Gson gson = new Gson();
SomePojoClass object = gson.fromJson(stringJson, SomePojoClass.class);

Note that you can not serialize objects with circular references. This causes infinite recursion.

edited Sep 8, 2015 at 15:46

The F

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answered Sep 8, 2015 at 15:10

Max Gontijo de Oliveira

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