如何从对象内部的数组中获取内部值？

Question

I want to get the values of latitude and longitude from the JSON, which consists of two objects "stoppage" & "routePlaceback", now I'm able to get data from "routePlaceback" only, but I have no clue how to get only the values of latitude and longitude? code is as follows,

import java.io.FileReader;
import java.util.ArrayList;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

public class Finder_Json 
{
@SuppressWarnings("rawtypes")
public static void main(String[] args) throws Exception  
{
// parsing JSON file
    Object sampleFile_object = new JSONParser().parse(new FileReader("sample.json")); 

// typecasting object to JSONObject 
    JSONObject sampleFile_JSONObject = (JSONObject) sampleFile_object;

    JSONArray routePlaceback = (JSONArray) sampleFile_JSONObject.get("routePlaceback");
    Iterator iterator_1 = routePlaceback.iterator();

    while (iterator_1.hasNext())
    {
        System.out.println(iterator_1.next());
        System.out.println("\n");
    }
}
}

My sample.json file consists,

{
"stoppage":
    [
        {
          "latitude": "23.074207",
          "longitude": "72.557227",
          "record_date": 1556217000,
          "start_time": 1556217000,
          "end_time": 1556304360,
          "duration_time": 1456
        }
    ],
"routePlaceback":

    [
        {
          "distance": 0.36,
          "longitude": "72.502385",
          "ignition": 1,
          "record_date": 1556303400,
          "speed": 53.708,
          "latitude": "23.034403"
        },
        {
          "distance": 0.38,
          "longitude": "72.506072",
          "ignition": 1,
          "record_date": 1556303430,
          "speed": 25.927999,
          "latitude": "23.034045"
        }
    ]
}

This is what I get when I run the above code,

But my desired output is as,

23.034403, 72.502385

23.034045, 72.506072

Answer 1

You can extract the required values while displaying:

while (iterator_1.hasNext())
{
    JSONObject obj = (JSONObject) iterator_1.next()l
    System.out.println(obj.get("latitude")+" , "+obj.get("longitude"));
    System.out.println("\n");
}

Answer 2

Here is your while loop modified :

while (iterator_1.hasNext()){
        JSONObject next = (JSONObject) iterator_1.next();
        System.out.print(next.get("latitude") + ", " + next.get("longitude"));
        System.out.println("\n");
}

Just get "latitude" and "longitude" property of object that iterator_1.next() returns. Moreover System.out.println(); prints new line already, System.out.println("\\n); actually prints two new lines. I don't know if it was intended by you.

Answer 3

You are trying to access the property of an Object where you can get the Object .

while (iterator_1.hasNext())
    {
       JSONObject k= (JSONObject)iterator_1.next()
        System.out.println(k.latitude+" "+k.longitude);
        System.out.println("\n");
    }

Answer 4

I modified a little bit your code to achieve your target. Please find the example below:

import java.io.FileReader;
import java.util.Iterator;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

public class Finder_Json 
{
    @SuppressWarnings("rawtypes")
    public static void main(String[] args) throws Exception  
    {
        // parsing JSON file
        Object sampleFile_object = new JSONParser().parse(new FileReader("src/main/resources/sample.json")); 

        // typecasting object to JSONObject 
        JSONObject sampleFile_JSONObject = (JSONObject) sampleFile_object;

        JSONArray routePlaceback = (JSONArray) sampleFile_JSONObject.get("routePlaceback");

        Iterator iterator = routePlaceback.iterator();
        while (iterator.hasNext()) {
            JSONObject objt = (JSONObject) iterator.next();
            System.out.println(objt.get("latitude") + ", " + objt.get("longitude"));
        }

    }
}

I strongly suggest to use Other libraries like GSON or Jackson anyway.