json decode java code example
Example 1: how to parse json in java
import org.json.*;
String jsonString = ... ; //assign your JSON String here
JSONObject obj = new JSONObject(jsonString);
String pageName = obj.getJSONObject("pageInfo").getString("pageName");
JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++)
{
String post_id = arr.getJSONObject(i).getString("post_id");
......
}
Example 2: java parse json
//from object to JSON
Gson gson = new Gson();
gson.toJson(yourObject);
// from JSON to object
yourObject o = gson.fromJson(JSONString,yourObject.class);
Example 3: decode json file in java tutorial
package com.howtodoinjava.demo.jsonsimple;
import java.io.FileWriter;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
public class WriteJSONExample
{
@SuppressWarnings("unchecked")
public static void main( String[] args )
{
//First Employee
JSONObject employeeDetails = new JSONObject();
employeeDetails.put("firstName", "Lokesh");
employeeDetails.put("lastName", "Gupta");
employeeDetails.put("website", "howtodoinjava.com");
JSONObject employeeObject = new JSONObject();
employeeObject.put("employee", employeeDetails);
//Second Employee
JSONObject employeeDetails2 = new JSONObject();
employeeDetails2.put("firstName", "Brian");
employeeDetails2.put("lastName", "Schultz");
employeeDetails2.put("website", "example.com");
JSONObject employeeObject2 = new JSONObject();
employeeObject2.put("employee", employeeDetails2);
//Add employees to list
JSONArray employeeList = new JSONArray();
employeeList.add(employeeObject);
employeeList.add(employeeObject2);
//Write JSON file
try (FileWriter file = new FileWriter("employees.json")) {
file.write(employeeList.toJSONString());
file.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Example 4: decode json file in java tutorial
package com.howtodoinjava.demo.jsonsimple;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
public class ReadJSONExample
{
@SuppressWarnings("unchecked")
public static void main(String[] args)
{
//JSON parser object to parse read file
JSONParser jsonParser = new JSONParser();
try (FileReader reader = new FileReader("employees.json"))
{
//Read JSON file
Object obj = jsonParser.parse(reader);
JSONArray employeeList = (JSONArray) obj;
System.out.println(employeeList);
//Iterate over employee array
employeeList.forEach( emp -> parseEmployeeObject( (JSONObject) emp ) );
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
}
}
private static void parseEmployeeObject(JSONObject employee)
{
//Get employee object within list
JSONObject employeeObject = (JSONObject) employee.get("employee");
//Get employee first name
String firstName = (String) employeeObject.get("firstName");
System.out.println(firstName);
//Get employee last name
String lastName = (String) employeeObject.get("lastName");
System.out.println(lastName);
//Get employee website name
String website = (String) employeeObject.get("website");
System.out.println(website);
}
}