Convert JSONArray to String Array

Question

I want to ask a question about converting a jsonArray to a StringArray on Android. Here is my code to get jsonArray from server.

try {
    DefaultHttpClient defaultClient = new DefaultHttpClient();
    HttpGet httpGetRequest = new HttpGet("http://server/android/listdir.php");
    HttpResponse httpResponse = defaultClient.execute(httpGetRequest);

    BufferedReader reader = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent(),"UTF-8"));

    String json = reader.readLine();

    //JSONObject jsonObject = new JSONObject(json);
    JSONArray jsonArray = new JSONArray(json);
    Log.d("", json);

    //Toast.makeText(getApplicationContext(), json, Toast.LENGTH_SHORT).show();

} catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

And this is the JSON.

[
    {"name": "IMG_20130403_140457.jpg"},
    {"name":"IMG_20130403_145006.jpg"},
    {"name":"IMG_20130403_145112.jpg"},
    {"name":"IMG_20130404_085559.jpg"},
    {"name":"IMG_20130404_113700.jpg"},
    {"name":"IMG_20130404_113713.jpg"},
    {"name":"IMG_20130404_135706.jpg"},
    {"name":"IMG_20130404_161501.jpg"},
    {"name":"IMG_20130405_082413.jpg"},
    {"name":"IMG_20130405_104212.jpg"},
    {"name":"IMG_20130405_160524.jpg"},
    {"name":"IMG_20130408_082456.jpg"},
    {"name":"test.jpg"}
]

How can I convert jsonArray that I've got to StringArray so I can get StringArray like this:

array = {"IMG_20130403_140457.jpg","IMG_20130403_145006.jpg",........,"test.jpg"};

Thank you for your help :)

Why would you want to convert a JSONArray which you showed to an ArrayList or an Array.Any special use? — Nezam
– Nezam, Commented Apr 8, 2013 at 4:51
stackoverflow.com/a/55691694/470749 was helpful for me. list.add(item.getAsString()); — Ryan
– Ryan, Commented Mar 22, 2021 at 16:16

Nicholas K · Accepted Answer · 2019-03-26 06:27:59Z

78

Take a look at this tutorial. Also you can parse above json like :

JSONArray arr = new JSONArray(yourJSONresponse);
List<String> list = new ArrayList<String>();
for(int i = 0; i < arr.length(); i++){
    list.add(arr.getJSONObject(i).getString("name"));
}

edited Mar 26, 2019 at 6:27

Nicholas K

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answered Apr 8, 2013 at 4:37

Saad Asad

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3 Comments

caknia Over a year ago

this convert to Array List first, then I can convert again to StringArray, thank to give an idea... (y)

Menachem Hornbacher Over a year ago

You can use list.add(arr.getString(i) just as well

Christopher Schultz Over a year ago

Since the length of the array is known, the ArrayList should be constructed with an explicit size (e.g. new ArrayList<String>(arr.length()).

JohnK · Accepted Answer · 2022-06-30 14:25:10Z

34

Simplest and correct code is:

public static String[] toStringArray(JSONArray array) {
    if(array==null)
        return new String[0];
    
    String[] arr=new String[array.length()];
    for(int i=0; i<arr.length; i++) {
        arr[i]=array.optString(i);
    }
    return arr;
}

Using List<String> is not a good idea, as you know the length of the array. Observe that it uses arr.length in for condition to avoid calling a method, i.e. array.length(), on each loop.

edited Jun 30, 2022 at 14:25

JohnK

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answered Oct 29, 2015 at 18:08

begrossi

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Comments

Ignacio Lago · Accepted Answer · 2017-05-16 16:27:27Z

14

public static String[] getStringArray(JSONArray jsonArray) {
    String[] stringArray = null;
    if (jsonArray != null) {
        int length = jsonArray.length();
        stringArray = new String[length];
        for (int i = 0; i < length; i++) {
            stringArray[i] = jsonArray.optString(i);
        }
    }
    return stringArray;
}

edited May 16, 2017 at 16:27

Ignacio Lago

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answered Jun 5, 2014 at 9:01

toddsalpen

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2 Comments

indivisible Over a year ago

Code only answers, while they may be correct, are rarely as informative as ones that also explain why. Consider adding some comments or an explanation to your post.

android developer Over a year ago

Checking if "jsonArray" is null after using it - is wrong as you might get NPE before the check itself.

drew moore · Accepted Answer · 2022-09-15 00:27:00Z

10

TERRIBLE TERRIBLE TERRIBLE hack:

String[] arr = jsonArray.toString().replace("},{", " ,").split(" ");

edited Sep 15, 2022 at 0:27

answered Apr 8, 2013 at 4:36

drew moore

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2 Comments

youseeus Over a year ago

this is insecure: [ { "name" : "},{" }, ... ]

youseeus Over a year ago

the problem is, that, if some string contains json (like "},{"), it would be splitted too.

Bhushan Bhangale · Accepted Answer · 2013-04-08 04:39:21Z

8

You can loop to create the String

List<String> list = new ArrayList<String>();
for (int i=0; i<jsonArray.length(); i++) {
    list.add( jsonArray.getString(i) );
}
String[] stringArray = list.toArray(new String[list.size()]);

answered Apr 8, 2013 at 4:39

Bhushan Bhangale

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Comments

YouBee · Accepted Answer · 2020-07-23 05:20:08Z

8

Was trying one of the same scenario but found one different and simple solution to convert JSONArray into List.

import java.lang.reflect.Type;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

String jsonStringArray = "[\"JSON\",\"To\",\"Java\"]";                 
    
//creating Gson instance to convert JSON array to Java array
                   
    Gson converter = new Gson();                  
    Type type = new TypeToken<List<String>>(){}.getType();
    List<String> list =  converter.fromJson(jsonStringArray, type );

Give a try

edited Jul 23, 2020 at 5:20

answered Jul 18, 2019 at 10:23

YouBee

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Comments

Visruth · Accepted Answer · 2014-06-26 14:57:14Z

3

Here is the code :

// XXX satisfies only with this particular string format
        String s = "[{\"name\":\"IMG_20130403_140457.jpg\"},{\"name\":\"IMG_20130403_145006.jpg\"},{\"name\":\"IMG_20130403_145112.jpg\"},{\"name\":\"IMG_20130404_085559.jpg\"},{\"name\":\"IMG_20130404_113700.jpg\"},{\"name\":\"IMG_20130404_113713.jpg\"},{\"name\":\"IMG_20130404_135706.jpg\"},{\"name\":\"IMG_20130404_161501.jpg\"},{\"name\":\"IMG_20130405_082413.jpg\"},{\"name\":\"IMG_20130405_104212.jpg\"},{\"name\":\"IMG_20130405_160524.jpg\"},{\"name\":\"IMG_20130408_082456.jpg\"},{\"name\":\"test.jpg\"}]";
        s = s.replace("[", "").replace("]", "");
        s = s.substring(1, s.length() - 1);
        String[] split = s.split("[}][,][{]");
        for (String string : split) {
            System.out.println(string);
        }

edited Jun 26, 2014 at 14:57

answered Apr 8, 2013 at 4:52

Visruth

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4 Comments

caknia Over a year ago

hmm, I would like if the code is for dynamic data.. but thank you for your answer... :)

Visruth Over a year ago

@andikurnia You have to get the dynamic data in s. please accept the answer if it works for you.

Michael Munsey Over a year ago

I think this would fail if there were escaped brackets ([) within the JSON.

Visruth Over a year ago

@Michael Munsey, It will not fail if the key or value contains [, but the result will not contain [, see s = s.replace("[", "").replace("]", "");. And, I have also mentioned satisfies only with this particular string format. This code should be improved based on @andikurnia's requirement.

Furkan Uyanik · Accepted Answer · 2021-09-26 18:47:28Z

2

The below code will convert JSON array to List

For example;

import org.json.JSONArray

String data = "YOUR_JSON_ARRAY_DATA";
JSONArray arr = new JSONArray(data);
List<String> list = arr.toList().stream().map(Object::toString).collect(Collectors.toList());

edited Sep 26, 2021 at 18:47

answered Sep 25, 2021 at 23:25

Furkan Uyanik

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2 Comments

DavidW Over a year ago

You should make it clear what this compared to the existing answers (which superficially look quite similar). It also doesn't look like you use data.

Furkan Uyanik Over a year ago

I am so sorry. I updated my answer. Thank you for feedback!

Wops · Accepted Answer · 2015-01-18 14:41:41Z

1

There you go:

String tempNames = jsonObj.names().toString();  
String[] types = tempNames.substring(1, tempNames.length()-1).split(","); //remove [ and ] , then split by ','

answered Jan 18, 2015 at 14:41

Wops

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1 Comment

youseeus Over a year ago

this is dangerous, cause there could be other occurrence of "," in the data

Leo · Accepted Answer · 2017-01-10 09:25:51Z

1

Using only the portable JAVA API. http://www.oracle.com/technetwork/articles/java/json-1973242.html

    try (JsonReader reader = Json.createReader(new StringReader(yourJSONresponse))) {
        JsonArray arr = reader.readArray();

        List<String> l = arr.getValuesAs(JsonObject.class)
            .stream().map(o -> o.getString("name")).collect(Collectors.toList());
    }

answered Jan 10, 2017 at 9:25

Leo

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Comments

Zon · Accepted Answer · 2017-05-23 04:57:34Z

A ready-to-use method:

/**
* Convert JSONArray to ArrayList<String>.
* 
* @param jsonArray JSON array.
* @return String array.
*/
public static ArrayList<String> toStringArrayList(JSONArray jsonArray) {

  ArrayList<String> stringArray = new ArrayList<String>();
  int arrayIndex;
  JSONObject jsonArrayItem;
  String jsonArrayItemKey;

  for (
    arrayIndex = 0;
    arrayIndex < jsonArray.length();
    arrayIndex++) {

    try {
      jsonArrayItem =
        jsonArray.getJSONObject(
          arrayIndex);

      jsonArrayItemKey =
        jsonArrayItem.getString(
          "name");

      stringArray.add(
        jsonArrayItemKey);
    } catch (JSONException e) {
      e.printStackTrace();
    }
  }

  return stringArray;
}

Alex Seguin · Accepted Answer · 2019-01-18 18:03:44Z

1

Bit late for an answer, but here's what I came up with using Gson:

for a jsonarray foo: [{"test": "bar"}, {"test": "bar2"}]

JsonArray foo = getJsonFromWherever();
String[] test = new String[foo.size()]
foo.forEach(x -> {test = ArrayUtils.add(test, x.get("test").getAsString());});

answered Jan 18, 2019 at 18:03

Alex Seguin

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Comments

Itération 122442 · Accepted Answer · 2020-01-06 13:11:54Z

1

I do post an answer here for the question here that was closed even though the asnwers here helped, but were not sufficient.

So, this is in order to get a json array to a String[] using jsonsimple.

According to the (marvelous) decode examples and docs, JSONArrays are java List, so we can access List methods.

From there, is it possible to transform it to a String[] with the following:

    JSONObject assemblingTags = (JSONObject) obj.get("assembling-tags");
    JSONArray aTagsList = (JSONArray) assemblingTags.get("list");
    String[] tagsList = (String[]) aTagsList.stream().toArray(String[]::new);

answered Jan 6, 2020 at 13:11

Itération 122442

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Comments

ucMax · Accepted Answer · 2021-08-27 14:25:31Z

1

And here is my solution, You may want to convert and merge more than a single array :

public static String[] multiJsonArrayToSingleStringArray(JSONArray... arrays) {
    ArrayList<String> list=new ArrayList<>();
    for (JSONArray array : arrays)
        for (int i = 0; i < array.length(); i++)
            list.add(array.optString(i));

    return list.toArray(new String[list.size()]);
}

answered Aug 27, 2021 at 14:25

ucMax

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Comments

MUGABA · Accepted Answer · 2022-11-08 14:20:04Z

1

I know this is probably late. I hope it will help someone.

When you have a string array that is stringfied. say something like this

String chars =  "["a","b","c"]";// Json stringfied string
List<String>charArray = (List<String>) JSON.parse(chars);

String[] stringArray = cars.toArray(new String[char.size()]);

There you go the array has something like this

 stringarray = ["a","b","c"];

answered Nov 8, 2022 at 14:20

MUGABA

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Comments

Januka samaranyake · Accepted Answer · 2017-01-29 13:57:43Z

0

You can input json array to this function get output as string array

example Input - { "gender" : ["male", "female"] }

output - {"male", "female"}

private String[] convertToStringArray(Object array) throws Exception {
   return StringUtils.stripAll(array.toString().substring(1, array.toString().length()-1).split(","));
}

edited Jan 29, 2017 at 13:57

answered Jan 29, 2017 at 7:23

Januka samaranyake

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2 Comments

Joe C Over a year ago

While you may have solved this user's problem, code-only answers are not very helpful to users who come to this question in the future. Please edit your answer to explain why your code solves the original problem.

Mbuodile Obiosio Over a year ago

Incomplete answer. If you must provide answers then include and explanation and the extra utils

Cjo · Accepted Answer · 2018-07-06 06:41:20Z

0

The below code will convert the JSON array of the format

[{"version":"70.3.0;3"},{"version":"6R_16B000I_J4;3"},{"version":"46.3.0;3"},{"version":"20.3.0;2"},{"version":"4.1.3;0"},{"version":"10.3.0;1"}]

to List of String

[70.3.0;3, 6R_16B000I_J4;3, 46.3.0;3, 20.3.0;2, 4.1.3;0, 10.3.0;1]

Code :

ObjectMapper mapper = new ObjectMapper(); ArrayNode node = (ArrayNode)mapper.readTree(dataFromDb); data = node.findValuesAsText("version"); // "version" is the node in the JSON

and use com.fasterxml.jackson.databind.ObjectMapper

answered Jul 6, 2018 at 6:41

Cjo

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Comments

Samuel Philipp · Accepted Answer · 2019-07-23 21:36:10Z

You might want to take a look at JSONArray.toList(), which returns a List containing Maps and Lists, which represent your JSON structure. So you can use it with Java Streams like this:

JSONArray array = new JSONArray(jsonString);
List<String> result = array.toList().stream()
        .filter(Map.class::isInstance)
        .map(Map.class::cast)
        .map(o -> o.get("name"))
        .filter(String.class::isInstance)
        .map(String.class::cast)
        .collect(Collectors.toList());

This might just be useful even for more complex objects.

Alternatively you can just use an IntStream to iterate over all items in the JSONArray and map all names:

JSONArray array = new JSONArray(jsonString);
List<String> result = IntStream.range(0, array.length())
        .mapToObj(array::getJSONObject)
        .map(o -> o.getString("name"))
        .collect(Collectors.toList());

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