How to extract property from JSON embedded within JSON?

Question

This is the JSON String I am getting back from a URL and I would like to extract highDepth value from the below JSON String.

{
  "description": "",
  "bean": "com.hello.world",
  "stats": {
    "highDepth": 0,
    "lowDepth": 0
  }
}

I am using GSON here as I am new to GSON. How do I extract highDepth from the above JSON Strirng using GSON?

String jsonResponse = restTemplate.getForObject(url, String.class);

// parse jsonResponse to extract highDepth

This is a possible duplicate of: http://stackoverflow.com/questions/8233542/parse-a-nested-json-using-gson http://stackoverflow.com/questions/19169754/parsing-nested-json-data-using-gson http://stackoverflow.com/questions/4453006/java-gson-parsing-nested-within-nested — Zoneh, Apr 09 '14 at 06:07

Sotirios Delimanolis · Accepted Answer · 2014-04-09T06:26:04.453

2

You create a pair of POJOs

public class ResponsePojo {    
    private String description;
    private String bean;
    private Stats stats;  
    //getters and setters       
}

public class Stats {    
    private int highDepth;
    private int lowDepth;
    //getters and setters     
}

You then use that in the RestTemplate#getForObject(..) call

ResponsePojo pojo = restTemplate.getForObject(url, ResponsePojo.class);
int highDepth = pojo.getStats().getHighDepth();

No need for Gson.

Without POJOs, since RestTemplate by default uses Jackson, you can retrieve the JSON tree as an ObjectNode.

ObjectNode objectNode = restTemplate.getForObject(url, ObjectNode.class);
JsonNode highDepth = objectNode.get("stats").get("highDepth");
System.out.println(highDepth.asInt()); // if you're certain of the JSON you're getting.

edited Apr 09 '14 at 06:26

answered Apr 09 '14 at 06:08

Sotirios Delimanolis

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Thanks for suggestion. But suppose if I don't need any POJO in my use case. I just need to extract only that `highDepth` value - How would I do that then? – john Apr 09 '14 at 06:09
Man, you saved my week, I figured out that I can use com.fasterxml.jackson.databind.node.ObjectNode as a field of my POJO if I don't want to parse it or if it is dynamicly changes and should be parsed manually by Gson for example. – Vadim Kirilchuk Jun 03 '15 at 20:09

score 1 · Answer 2 · edited May 23 '17 at 12:32

1

Refering to JSON parsing using Gson for Java, I would write something like

JsonElement element = new JsonParser().parse(jsonResponse);
JsonObject rootObject = element.getAsJsonObject();
JsonObject statsObject = rootObject.getAsJsonObject("stats");
Integer highDepth = Integer.valueOf(statsObject.get("highDepth").toString());

edited May 23 '17 at 12:32

Community

1
1

answered Apr 09 '14 at 06:22

Smutje

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How to extract property from JSON embedded within JSON?

2 Answers2