How to access the nested field in json using Java?

Question

I have a big JSON file(demo.json). Here is how it looks like:

{  
   "preview":false,
   "result":{  
      "search_term":"rania",
      "request_time":"Sat Apr 01 12:47:04 -0400 2017",
      "request_ip":"127.0.0.1",
      "stats_type":"stats",
      "upi":"355658761",
      "unit":"DR",
      "job_title":"Communications Officer",
      "vpu":"INP",
      "organization":"73",
      "city":"Wash",
      "country":"DC",
      "title":"Tom",
      "url":"www.demo.com",
      "tab_name":"People-Tab",
      "page_name":"PEOPLE",
      "result_number":"5",
      "page_num":"0",
      "session_id":"df234f468cb3fe8be",
      "total_results":"5",
      "filter":"qterm=rina",
      "_time":"2017-04-01T12:47:04.000-0400"
   }
}
{"preview"......}
{"preview"......}
....

I would like to access search term and page_name which is inside of the result and convert them into the string . Below is my java code which is not working:

BufferedReader br = new BufferedReader(new FileReader("demo.json"));
String line;
while ((line = br.readLine()) != null) {

                JSONParser parser = new JSONParser();
                Object obj = parser.parse(line);
                JSONObject jsonObject = (JSONObject) obj;
                String searchterm= (String) jsonObject.get("search_term");
                String page_name = (String) jsonObject.get("page_name");
}

I am not familiar with how to access the nested fields and convert those into string. Any help is appreciated.

You're trying to parse each line. But { is not valid JSON. "preview":false, is not valid JSON either. — JB Nizet
– JB Nizet, Commented May 2, 2017 at 19:05
My JSON is valid. The one I posted was just for example. I want to know how to access the nested field search_term which is inside result — Rose
– Rose, Commented May 2, 2017 at 19:06

NastyDiaper · Accepted Answer · 2017-05-02 19:14:18Z

1

boolean preview = jsonObject.get("preview");
JSONObject result = jsonObject.getJSONObject("result");
String search_term = result.getString("search_term");
String page_name = result.getString("page_name");

edited May 2, 2017 at 19:14

answered May 2, 2017 at 19:07

NastyDiaper

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4 Comments

Rose Over a year ago

Thanks for the reply. Do I have to add any dependency in maven? I am getting an error on getJSONObject "getJSONObject(String) is undefined for the type JSONObject"

NastyDiaper Over a year ago

No you should just import org.json.JSONObject; stleary.github.io/JSON-java/org/json/JSONObject.html

Rose Over a year ago

I used the specified import, but I am getting an error "The import org.json.JSONObject cannot be resolved ". I have a maven dependency mvnrepository.com/artifact/com.googlecode.json-simple/… for another part of the program. Do you think this might be a problem?

NastyDiaper Over a year ago

Cha. Wrong library. Here's your repo. mvnrepository.com/artifact/org.json/json/20160810

Vikrant · Accepted Answer · 2017-05-02 19:11:32Z

0

You can use library like Gson .Convert the data into Map

    BufferedReader br = new BufferedReader(new FileReader("demo.json"));
String line;
StringBuilder builder=new StringBuilder();
while ((line = br.readLine()) != null) {
builder.append(line);

} 

       Type type = new TypeToken<Map<String, String>>(){}.getType();
       Map<String, String> myMap = gson.fromJson(builder.toString(), type);

You can use myMap to get Values for json Keys . For nested Key you can another convert it to Map again.

answered May 2, 2017 at 19:11

Vikrant

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Comments

ALUMOM · Accepted Answer · 2017-05-02 19:22:01Z

0

Use ObjectMapper to convert your JSON to PoJo and then use it.

answered May 2, 2017 at 19:22

ALUMOM

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