how to parse dynamic and nested json in java

How to parse a dynamic JSON key in a Nested JSON result?

stackoverflow.com › questions › 7304002 › how-to-parse-a-dynamic-json-key-in-a-nested-json-result

Use JSONObject keys() to get the key and then iterate each key to get to the dynamic value.

Roughly the code will look like:


// searchResult refers to the current element in the array "search_result" but whats searchResult?
JSONObject questionMark = searchResult.getJSONObject("question_mark");
Iterator keys = questionMark.keys();
    
while(keys.hasNext()) {
    // loop to get the dynamic key
    String currentDynamicKey = (String)keys.next();
        
    // get the value of the dynamic key
    JSONObject currentDynamicValue = questionMark.getJSONObject(currentDynamicKey);
        
        // do something here with the value...
}

Answer from momo on Stack Overflow

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stackoverflow.com › questions › 7304002 › how-to-parse-a-dynamic-json-key-in-a-nested-json-result

java - How to parse a dynamic JSON key in a Nested JSON result? - Stack Overflow

Top answer

1 of 5

123

Use JSONObject keys() to get the key and then iterate each key to get to the dynamic value.

Roughly the code will look like:


// searchResult refers to the current element in the array "search_result" but whats searchResult?
JSONObject questionMark = searchResult.getJSONObject("question_mark");
Iterator keys = questionMark.keys();
    
while(keys.hasNext()) {
    // loop to get the dynamic key
    String currentDynamicKey = (String)keys.next();
        
    // get the value of the dynamic key
    JSONObject currentDynamicValue = questionMark.getJSONObject(currentDynamicKey);
        
        // do something here with the value...
}

2 of 5

Another possibility is to use Gson (Note, I use lombok here to generates getters/setters, toString, etc):

package so7304002;

import java.util.List;
import java.util.Map;

import lombok.AccessLevel;
import lombok.Data;
import lombok.NoArgsConstructor;

import com.google.gson.Gson;
import com.google.gson.annotations.SerializedName;
import com.google.gson.reflect.TypeToken;

@NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class JsonDemo {
    @Data
    private static class MyMap {
        private int count;

        @SerializedName("more_description")
        private String moreDescription;

        private int seq;
    }

    @Data
    private static class Product {
        private String product;

        private int id;

        @SerializedName("question_mark")
        private Map<String, MyMap> questionMark;
    }

    @Data
    private static class MyObject {
        private String status;

        @SerializedName("search_result")
        private List<Product> searchResult;
    }

    private static final String INPUT = ""; // your JSON

    public static void main(final String[] arg) {
        final MyObject fromJson = new Gson().fromJson(INPUT, 
            new TypeToken<MyObject>(){}.getType());
        final List<Product> searchResult = fromJson.getSearchResult();
        for (final Product p : searchResult) {
            System.out.println("product: " + p.getProduct() 
                + "\n" + p.getQuestionMark()+ "\n");
        }
    }
}

Output:

product: abc
{141=JsonDemo.MyMap(count=141, moreDescription=this is abc, seq=2), 
 8911=JsonDemo.MyMap(count=8911, moreDescription=null, seq=1)}

product: XYZ
{379=JsonDemo.MyMap(count=379, moreDescription=null, seq=5), 
 845=JsonDemo.MyMap(count=845, moreDescription=null, seq=6), 
 12383=JsonDemo.MyMap(count=12383, moreDescription=null, seq=4), 
 257258=JsonDemo.MyMap(count=257258, moreDescription=null, seq=1)}

reddit.com › r/javahelp › parsing a json object with nested dynamic values (with known keys)

r/javahelp on Reddit: Parsing a JSON object with nested dynamic values (with known keys)

October 16, 2024 -

In a problem I am working on, I have an endpoint where I will need to receive a JSON object which have a key that might contain different objects depending on the call. The list of possible objects is known in advance, but I am struggling with how best to model it. Splitting the endpoint into multiple is not an option.

The example looks something like this:

outerObject {
  ...,
  key: object1 | object2 | object3
}

object1 {
  "a": "a"
  "b": "b"
}

object2 {
  "c": 2
  "d": "d"
}

object3 {
  "e": 3,
  "f": 4
}

If I was writing it in Rust I would use an `enum` with structs for each of the different objects. This is for Java 21, so using sealed types is not yet an option (I might be able to upgrade, but I am not sure if the different

Using either Jackson or Gson I was think of representing it in one of their Json structures and then determining which object fits when the call is made.

Is this the best option or are there any more generic solutions?

Top answer

1 of 4

like that? https://stackoverflow.com/a/32777371

2 of 4

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