how to parse nested json array in java

Question

I would like to parse netsted json in Java: Below is json string:

[
    {
        "id": 1,
        "empid": "12345",
        "details": {
            "name": "xyz",
            "age": "30",
            "sex": "M",
            "Address": {
                "Office": "office",
                "Home": "Home"
            }
        },
        "abcDetails": "asdf",
        "mobile": 123455
    },
    {
        "id": 2,
        "empid": "64848",
        "details": {
            "name": "eryje",
            "age": 3027,
            "sex": "M",
            "Address": {
                "Office": "office",
                "Home": "Home"
            }
        },
        "abcDetails": "fhkdl",
        "mobile": 389928
    }
]

I need name, age details from above json, can someone help how to parse these value in java, i tried the below code to get those value - it seems its nested and not sure how to get those value.

        JSONArray jsonarray = new JSONArray(str);
        for (int i = 0; i < jsonarray.length(); i++) {
            JSONObject obj1 = jsonarray.getJSONObject(i);

            String name = obj1.getString("name");
            String age = obj1.getString("age");

            System.out.println(name);
            System.out.println(age);
        }

Why you dont try to parse JSON using this library: code.google.com/p/json-simple. :) — Leo
– Leo, Commented Jul 17, 2015 at 1:25
I'm getting this exception - if I try to use getString("name") - org.json.JSONException: JSONObject["name"] not found. at org.json.JSONObject.get(JSONObject.java:498) at org.json.JSONObject.getString(JSONObject.java:669) — learn java
– learn java, Commented Jul 17, 2015 at 1:31

hiropon · Accepted Answer · 2015-07-17 01:55:09Z

You probably need to use #getJSONObject() for getting nested object.

But, this is my personal impression, why org.json package's version strings are date format ? Probably it's not good library...

Example:

package testing;

import org.json.JSONArray;
import org.json.JSONObject;

/**
 * Hello world!
 */
public class App {

    static String json = ""
 + "["
 + " {"
 + "     \"id\": 1,"
 + "     \"empid\": \"12345\","
 + "     \"details\": {"
 + "         \"name\": \"xyz\","
 + "         \"age\": \"30\","
 + "         \"sex\": \"M\","
 + "         \"Address\": {"
 + "             \"Office\": \"office\","
 + "             \"Home\": \"Home\""
 + "         }"
 + "     },"
 + "     \"abcDetails\": \"asdf\","
 + "     \"mobile\": 123455"
 + " },"
 + " {"
 + "     \"id\": 2,"
 + "     \"empid\": \"64848\","
 + "     \"details\": {"
 + "         \"name\": \"eryje\","
 + "         \"age\": 3027,"
 + "         \"sex\": \"M\","
 + "         \"Address\": {"
 + "             \"Office\": \"office\","
 + "             \"Home\": \"Home\""
 + "         }"
 + "     },"
 + "     \"abcDetails\": \"fhkdl\","
 + "     \"mobile\": 389928"
 + " }"
 + "]";

    public static void main(String[] args) throws Exception {

        JSONArray jsonarray = new JSONArray(json);
        System.out.println(String.format("JSONArray length => %d", jsonarray.length()));

        for (int i = 0; i < jsonarray.length(); i++) {
            JSONObject obj1 = jsonarray.getJSONObject(i);
            JSONObject details = obj1.getJSONObject("details");
            System.out.println(String.format("details => %s", details.toString()));

            String name = details.getString("name");
            int age = details.getInt("age");
            System.out.println(name);
            System.out.println(age);
        }
    }
}

Results:

$ mvn exec:java -Dexec.mainClass="testing.App"
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building testing 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> exec-maven-plugin:1.2.1:java (default-cli) @ testing >>>
[INFO]
[INFO] <<< exec-maven-plugin:1.2.1:java (default-cli) @ testing <<<
[INFO]
[INFO] --- exec-maven-plugin:1.2.1:java (default-cli) @ testing ---
JSONArray length => 2
details => {"sex":"M","Address":{"Home":"Home","Office":"office"},"age":"30","name":"xyz"}
xyz
30
details => {"sex":"M","Address":{"Home":"Home","Office":"office"},"age":3027,"name":"eryje"}
eryje
3027
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.576s
[INFO] Finished at: Fri Jul 17 10:46:29 JST 2015
[INFO] Final Memory: 7M/106M
[INFO] ------------------------------------------------------------------------

Thanks you! It works. But I've scenario like some time i'll get the json without "details" object also.. Like below - [ { "id": 1, "empid": "12345", "details": { "name": "xyz", "age": "30", "sex": "M", "Address": { "Office": "office", "Home": "Home" } }, "abcDetails": "asdf", "mobile": 123455 }, { "id": 2, "empid": "64848", "abcDetails": "fhkdl", "mobile": 389928 } ] In this case - how to handle it?
@learnjava See also javadoc of #keys or #has. Probably, you should check JSON keys before getting it. If key doesn't exist, you call continue statement in for loop.

xy1m · Accepted Answer · 2015-07-17 02:05:26Z

The property name and age are in the details Try this code

JSONArray jsonarray = new JSONArray(str);
        for (int i = 0; i < jsonarray.length(); i++) {
            JSONObject obj1 = jsonarray.getJSONObject(i);
            JSONObject details = obj1.getJSONObject("details");
            String name = details.getString("name");
            String age = details.getString("age");

            System.out.println(name);
            System.out.println(age);
        }

Scary Wombat · Accepted Answer · 2015-07-17 01:57:18Z

0

In your code your are doing

String name = obj1.getString("name");

but name is a sub-element of detail so you need to get the detail object first.

JSONObject detail = obj1.getJSONObject("details");

and then

String name = detail.getString("name");

answered Jul 17, 2015 at 1:57

Scary Wombat

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2 Comments

learn java Over a year ago

Thanks for the response. But i've scenario sometime I wont receive "details" object like this - [ { "id": 1, "empid": "12345", "details": { "name": "xyz", "age": "30", "sex": "M", "Address": { "Office": "office", "Home": "Home" } }, "abcDetails": "asdf", "mobile": 123455 }, { "id": 2, "empid": "64848", "abcDetails": "fhkdl", "mobile": 389928 } ] - How to handle this scenario

Scary Wombat Over a year ago

wrap in up in an try/catch block catching the JSONException see json.org/javadoc/org/json/…

Mateo · Accepted Answer · 2019-10-02 21:18:31Z

//import java.util.ArrayList;
//import org.bson.Document;

Document root= Document.parse("{\"records\":[\n" +
"    {\n" +
"        \"id\": 1,\n" +
"        \"empid\": \"12345\",\n" +
"        \"details\": {\n" +
"            \"name\": \"xyz\",\n" +
"            \"age\": \"30\",\n" +
"            \"sex\": \"M\",\n" +
"            \"Address\": {\n" +
"                \"Office\": \"office\",\n" +
"                \"Home\": \"Home\"\n" +
"            }\n" +
"        },\n" +
"        \"abcDetails\": \"asdf\",\n" +
"        \"mobile\": 123455\n" +
"    },\n" +
"    {\n" +
"        \"id\": 2,\n" +
"        \"empid\": \"64848\",\n" +
"        \"details\": {\n" +
"            \"name\": \"eryje\",\n" +
"            \"age\": 3027,\n" +
"            \"sex\": \"M\",\n" +
"            \"Address\": {\n" +
"                \"Office\": \"office\",\n" +
"                \"Home\": \"Home\"\n" +
"            }\n" +
"        },\n" +
"        \"abcDetails\": \"fhkdl\",\n" +
"        \"mobile\": 389928\n" +
"    }\n" +
"]}");


System.out.println((((Document)((ArrayList)root.get("records")).get(0)).get("id")));
System.out.println(((String)((Document)((ArrayList)root.get("records")).get(0)).get("empid")));
System.out.println(((String)((Document)((Document)((ArrayList)root.get("records")).get(0)).get("details")).get("name")));
System.out.println(((String)((Document)((Document)((ArrayList)root.get("records")).get(0)).get("details")).get("age")));
System.out.println(((String)((Document)((Document)((ArrayList)root.get("records")).get(0)).get("details")).get("sex")));
System.out.println(((String)((Document)((Document)((Document)((ArrayList)root.get("records")).get(0)).get("details")).get("Address")).get("Office")));
System.out.println(((String)((Document)((Document)((Document)((ArrayList)root.get("records")).get(0)).get("details")).get("Address")).get("Home")));
System.out.println(((String)((Document)((ArrayList)root.get("records")).get(0)).get("abcDetails")));
System.out.println((((Document)((ArrayList)root.get("records")).get(0)).get("mobile")));
System.out.println((((Document)((ArrayList)root.get("records")).get(1)).get("id")));
System.out.println(((String)((Document)((ArrayList)root.get("records")).get(1)).get("empid")));
System.out.println(((String)((Document)((Document)((ArrayList)root.get("records")).get(1)).get("details")).get("name")));
System.out.println((((Document)((Document)((ArrayList)root.get("records")).get(1)).get("details")).get("age")));
System.out.println(((String)((Document)((Document)((ArrayList)root.get("records")).get(1)).get("details")).get("sex")));
System.out.println(((String)((Document)((Document)((Document)((ArrayList)root.get("records")).get(1)).get("details")).get("Address")).get("Office")));
System.out.println(((String)((Document)((Document)((Document)((ArrayList)root.get("records")).get(1)).get("details")).get("Address")).get("Home")));
System.out.println(((String)((Document)((ArrayList)root.get("records")).get(1)).get("abcDetails")));
System.out.println((((Document)((ArrayList)root.get("records")).get(1)).get("mobile")));

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