Here is a simple Java tutorial which demonstrate how to parse JSONObject and JSONArrays in Java.
JSON syntax is a subset of the JavaScript object notation syntax:
- Data is in name/value pairs
- Data is separated by commas
- Curly braces hold objects
- Square brackets hold arrays
Just incase if you want to take a look at simple JSON tutorial which I’ve written sometime back. In this example we will read JSON File Crunchify_JSON.txt from file system and then we will iterate through it.
In order to run below Java project, please add below Maven Dependency to your project in pom.xml file.
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<dependency> <groupId>org.json</groupId> <artifactId>json</artifactId> <version>20151123</version> </dependency> |
Create this .txt file and update path in Java project:
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{ "blogURL": "https://crunchify.com", "twitter": "https://twitter.com/Crunchify", "social": { "facebook": "http://facebook.com/Crunchify", "pinterest": "https://www.pinterest.com/Crunchify/crunchify-articles", "rss": "http://feeds.feedburner.com/Crunchify" } } |
Java Program:
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package com.crunchify.tutorials; import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import org.json.JSONException; import org.json.JSONObject; /** * @author Crunchify.com * */ public class CrunchifyParseJSONObject { public static void main(String[] args) throws FileNotFoundException, JSONException { String jsonData = ""; BufferedReader br = null; try { String line; br = new BufferedReader(new FileReader("/Users/<username>/Documents/Crunchify_JSON.txt")); while ((line = br.readLine()) != null) { jsonData += line + "\n"; } } catch (IOException e) { e.printStackTrace(); } finally { try { if (br != null) br.close(); } catch (IOException ex) { ex.printStackTrace(); } } // System.out.println("File Content: \n" + jsonData); JSONObject obj = new JSONObject(jsonData); System.out.println("blogURL: " + obj.getString("blogURL")); System.out.println("twitter: " + obj.getString("twitter")); System.out.println("social: " + obj.getJSONObject("social")); } } |
Result:
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blogURL: https://crunchify.com twitter: https://twitter.com/Crunchify social: {"facebook":"http://facebook.com/Crunchify","rss":"http://feeds.feedburner.com/Crunchify","pinterest":"https://www.pinterest.com/Crunchify/crunchify-articles"} |
what library are you using ?
Hi Mulk – i’m using org.json maven library in this tutorial.
Are you getting any error? If you want to convert project to maven project then you could follow this tutorial: https://crunchify.com/how-to-convert-existing-java-project-to-maven-in-eclipse/
Hello Sir, I need some help from you. Actually i’m getting JSON data from a url and i want to show the data on my website. I
Successfully showing all JSON data except JSON Hierarchy data. I easily accessing Array data (“person”) and also in front
data(i.e “error”) but i can’t access hierarchy which is “updated”.
I have to access “updated.time”. I’m get very much frustrations in doing this. Can you help..?
import java.io.IOException;
import java.net.URL;
import org.apache.commons.io.IOUtils;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import org.json.simple.parser.ParseException;
public class ParseJson1 {
public static void main(String[] args) {
String url = “http://freemusicarchive.org/api/get/genres.json?api_key=60BLHNQCAOUFPIBZ&limit=2”;
*/
{
“person”: [
{
“name”: “John”,
“city”: “Mumbai”
},
{
“name”: “Rahul”,
“city”: “Delhi”
},
{
“name”: “Sanjana”,
“city”: “Amritsar”
},
{
“name”: “Anjali”,
“city”: “Hyderabad”
},
{
“name”: “Mukund”,
“city”: “Bangalore”
},
{
“name”: “Raunak”,
“city”: “Patna”
}
],
“updated”: {
“time”: “14:17:48”,
“date”: “2016-04-10”
},
“error”: “2353”,
}
/*
try {
String genreJson = IOUtils.toString(new URL(url));
JSONObject genreJsonObject = (JSONObject) JSONValue.parseWithException(genreJson);
// get the error
System.out.println(genreJsonObject.get(“error”));
//Get Array Values
JSONArray genreArray = (JSONArray) genreJsonObject.get(“person”);
// get the first genre
JSONObject firstGenre = (JSONObject) genreArray.get(0);
System.out.println(firstGenre.get(“name”));
// get the Second
JSONObject firstGenre = (JSONObject) genreArray.get(1);
System.out.println(firstGenre.get(“name”));
// get the third
JSONObject firstGenre = (JSONObject) genreArray.get(2);
System.out.println(firstGenre.get(“city”));
} catch (IOException | ParseException e) {
e.printStackTrace();
}
}
}
Hi Subham –
Here is a program to get Updated.time from JSON Object.
package crunchify.com.tutorials; import java.io.FileReader; import java.io.IOException; import org.json.simple.JSONObject; import org.json.simple.parser.JSONParser; import org.json.simple.parser.ParseException; /** * @author Crunchify.com * */ public class CrunchifyParseJSONObject { public static void main(String[] args) { JSONParser parser = new JSONParser(); try { Object obj = parser.parse(new FileReader("/Users/appshah/Documents/crunchify.txt")); JSONObject genreJsonObject = (JSONObject) obj; JSONObject updated = (JSONObject) genreJsonObject.get("updated"); String time = (String) updated.get("time"); System.out.println(time); } catch (IOException | ParseException e) { e.printStackTrace(); } } }Also, JSONObject I’m using is:
{ "person": [{ "name": "John", "city": "Mumbai" }, { "name": "Rahul", "city": "Delhi" }, { "name": "Sanjana", "city": "Amritsar" }, { "name": "Anjali", "city": "Hyderabad" }, { "name": "Mukund", "city": "Bangalore" }, { "name": "Raunak", "city": "Patna" }], "updated": { "time": "14:17:48", "date": "2016-04-10" } }when i am writing the below code in eclipse editor, It shows me syntax error in edirot and when i mouse hover it gives me 2 suggestiosn to fix :
1.Remove argument to match JSONObject
2.Change type of jsonData to map
public void getJSONData(String file) throws FileNotFoundException, JSONException {
String jsonData = “”;
BufferedReader br = null;
try {
String line;
br = new BufferedReader(new FileReader(file));
while ((line = br.readLine()) != null) {
jsonData += line + “n”;
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null)
br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
System.out.println(“File Content: n” + jsonData);
//return jsonData;
JSONObject obj = new JSONObject(jsonData);
System.out.println(“blogURL: ” + obj.getString(“blogURL”));
//System.out.println(“twitter: ” + obj.getString(“twitter”));
//System.out.println(“social: ” + obj.getJSONObject(“social”));
}
Make sure you clean your project and json dependency is added correctly. I just tried it on my eclipse and it worked fine.
even i am facing the same problem did you fix it ?
Hi Nidhi – I’ve just updated above tutorial with org.json dependency. Can you try now?
at the following line “JSONObject obj = new JSONObject(jsonData);” I am getting error “Remove argument to match json” Or “change type of jsonData to map”
Hi Shraddha – i didn’t get it. Can you help share screenshot or any exception you are getting?
Hi Shraddha – I’ve added org.json dependency in above project. Please update project once you add .jar to your project or update pom.xml file.