Create Java array from JSON in URL

Question

I have a URL. In it there is a straightforward JSON array in this format:

["england","france","germany","america","denmark","italy","greece","portugal","poland"]

All I need to do is read this from the Java, and put it into an ArrayList.

It sounded so simple, but I've been on it for hours.

This is what I've done so far:

package com.example.landmarksapp;

import java.io.BufferedReader;
import java.io.IOException; 
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;

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

/**
 * Fetches JSON results and returns into correct format for the GUI
 * @author Alicia
 *
 */
public class Conector {
    private String urlToCities = "http://jagdeep.co:8080/LandmarkServers-0.1/city/listJSON/";

    /**
     * Fetches list of cities
     * @param urlToCities the link to the JOSN file with the list of cities
     * @return ArrayList<String> of cities
     * @throws IOException
     * @throws JSONException
     */
    public List<String> fetchCities(String urlToCities) throws IOException, JSONException {
        List<String> result = new ArrayList();
        JSONObject jsonResults = readJsonFromUrl(urlToCities);  
        return result;
    }

    /**
     * @inheritDoc
     */
    public List<String> fetchCities() throws IOException, JSONException {
        return fetchCities(urlToCities);
    }

    /**
     * 
     * @param rd 
     * @return
     * @throws IOException
     */
    private String readAll(Reader rd) throws IOException {
        StringBuilder sb = new StringBuilder();
        int cp;
        while ((cp = rd.read()) != -1) {
            sb.append((char) cp);
            System.out.println(cp);
        }
        return sb.toString();
    }

    /**
     * 
     * @param url
     * @return
     * @throws IOException
     * @throws JSONException
     */
    private JSONObject readJsonFromUrl(String url) throws IOException, JSONException {
        InputStream is = new URL(url).openStream();
        try {
            BufferedReader rd = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
            String jsonText = readAll(rd);
            JSONObject json = new JSONObject(jsonText);
            return json;
        } finally {
            is.close();
        }
    }
}

Ravi K Thapliyal · Accepted Answer · 2013-10-26 21:53:24Z

1

Wrap the response text into JSONArray instead.

List<String> countries = new ArrayList<String>();
String json = "[\"england\",\"france\",\"germany\",\"america\"," +
        "\"denmark\",\"italey\",\"greece\",\"portugal\",\"poland\"]";

JSONArray countryArr = new JSONArray(json);
for (int i = 0; i < countryArr.length(); i++) {
    countries.add(countryArr.getString(i));
}
System.out.println(countries);

Output :

[england, france, germany, america, denmark, italey, greece, portugal, poland]

answered Oct 26, 2013 at 21:53

Ravi K Thapliyal

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