How to parse JSON from String represention of list of JSONs object?

Question

I have a string of the form

String str = "[
             {"id": 1, "name":"Abc", "Eligible": "yes"},
             {"id": 2, "name":"Def", "Eligible": "no"},
             {"id": 3, "name":"Ghi", "Eligible": "yes"},
             {"id": 4, "name":"Jkl", "Eligible": "no"}
             ]";

I want to parse each JSON from the list. Thank you.

@VictorPoloDeGyvesMontero I am still very confused about how to convert this string to list first. — Utkarsh, Jun 02 '21 at 07:22
Unfortunately this is very basic question and asked dozens of times here only. Did you try to research on this? — Pradeep Simha, Jun 02 '21 at 07:24
Yes, I do but can not find a solution. @PradeepSimha, I am confused because the list is a form of string. — Utkarsh, Jun 02 '21 at 07:26
I have no clue how to convert the string representation of list into the actual list because I can not simply split the from comma because JSON may also contain a comma. @PradeepSimha — Utkarsh, Jun 02 '21 at 07:37
That's what we are saying, if you search stackoverflow or see the duplicate question. You will get clue on this. Once you have clue and idea, that is the best time to ask new question here. — Pradeep Simha, Jun 02 '21 at 07:39
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/233223/discussion-between-utkarsh-and-pradeep-simha). — Utkarsh, Jun 02 '21 at 07:45

Manpreet Singh Bhinder · Answer 1 · 2021-06-02T08:25:45.640

Hi I can provide very crude answer to you question.

Add this dependecy in pom.xml

    <dependencies>
        ...
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.7</version>
        </dependency>
      ...
    </dependencies>

Jave Code:

 public static void main(String... args) {
       String str = "[ {\"id\": 1, \"name\":\"Abc\", \"Eligible\": \"yes\"}, {\"id\": 2, \"name\":\"Def\", \"Eligible\": \"no\"}, {\"id\": 3, \"name\":\"Ghi\", \"Eligible\": \"yes\"}, {\"id\": 4, \"name\":\"Jkl\", \"Eligible\": \"no\"}]";

        Gson gson = new Gson();
        Object o = gson.fromJson(str, Object.class);
        String name = ((LinkedTreeMap) ((ArrayList) o).get(0)).get("name").toString();
        System.out.println("name is "+ name);
}

Output:

name is Abc

score 0 · Answer 2 · answered Jun 02 '21 at 08:00

You can parse list from the input json string, there are multiple ways and different libraries you can use to parse.

Using json

Maven dependency :

<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20210307</version>
</dependency>

 String str = "[{\"id\":1,\"name\":\"Abc\",\"Eligible\":\"yes\"},{\"id\":2,\"name\":\"Def\",\"Eligible\":\"no\"},{\"id\":3,\"name\":\"Ghi\",\"Eligible\":\"yes\"},{\"id\":4,\"name\":\"Jkl\",\"Eligible\":\"no\"}]";

     JSONArray jsonArray = new JSONArray(str);

        for (int i = 0; i < jsonArray.length(); i++) {
            int id = ((JSONObject)jsonArray.get(i)).getInt("id");
            String name = ((JSONObject)jsonArray.get(i)).getString("name");
            String eligible = ((JSONObject)jsonArray.get(i)).getString("Eligible");
             
        }

Using google gson

Maven dependency

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.7</version>
</dependency>

Create a class for the object that corresponds to the object in the input list.

In your case it would be:

class Item{
        int id;
        String name;
        String Eligible;
        //getter setter
    }

String str = "[{\"id\":1,\"name\":\"Abc\",\"Eligible\":\"yes\"},{\"id\":2,\"name\":\"Def\",\"Eligible\":\"no\"},{\"id\":3,\"name\":\"Ghi\",\"Eligible\":\"yes\"},{\"id\":4,\"name\":\"Jkl\",\"Eligible\":\"no\"}]";
Type listType = new TypeToken<ArrayList<Item>>(){}.getType();
List<Item> items = new Gson().fromJson(str, listType);
for (Item item: items){
   //access the item
}

How to parse JSON from String represention of list of JSONs object?

2 Answers2