GSON/Jackson in Android

Question

I was able to successfully parse the below JSON string in Android using JSONObject and JSONArray. Have had no success achieving the same result with GSON or Jackson. Can som

Answer 1

Following are simple examples of using Gson and Jackson to deserialize/serialize JSON (similar to the invalid JSON in the original question) to/from a matching Java data structure.

The JSON:

{
    "response": {
        "status": 200
    },
    "items": [
        {
            "item": {
                "body": "Computing",
                "subject": "Math",
                "attachment": false
            }
        },
        {
            "item": {
                "body": "Analytics",
                "subject": "Quant",
                "attachment": true
            }
        }
    ],
    "score": 10,
    "thesis": {
        "submitted": false,
        "title": "Masters",
        "field": "Sciences"
    }
}

The Matching Java Data Structure:

class Thing
{
  Response response;
  ItemWrapper[] items;
  int score;
  Thesis thesis;
}

class Response
{
  int status;
}

class ItemWrapper
{
  Item item;
}

class Item
{
  String body;
  String subject;
  boolean attachment;
}

class Thesis
{
  boolean submitted;
  String title;
  String field;
}

Jackson Example:

import java.io.File;

import org.codehaus.jackson.annotate.JsonAutoDetect.Visibility;
import org.codehaus.jackson.map.ObjectMapper;

public class JacksonFoo
{
  public static void main(String[] args) throws Exception
  {
    ObjectMapper mapper = new ObjectMapper();  
    mapper.setVisibilityChecker(  
      mapper.getVisibilityChecker()  
        .withFieldVisibility(Visibility.ANY));
    Thing thing = mapper.readValue(new File("input.json"), Thing.class);
    System.out.println(mapper.writeValueAsString(thing));
  }
}

Gson Example:

import java.io.FileReader;

import com.google.gson.Gson;

public class GsonFoo
{
  public static void main(String[] args) throws Exception
  {
    Gson gson = new Gson();
    Thing thing = gson.fromJson(new FileReader("input.json"), Thing.class);
    System.out.println(gson.toJson(thing));
  }
}