Develop Reference

Gson: Expected begin_array but was STRING how to control this

Im learning how to produce and consume JSON in rest services, but I wanna learn it well so im trying all possible cases of objects, one of them is an object that has an List attribute like this class:
import java.util.List;
public class PruebaJSON {
private String nombre;
private List atributos;
private String descripcion;
public String getNombre() {
return nombre;
}
public void setNombre(String nombre) {
this.nombre = nombre;
}
public List getAtributos() {
return atributos;
}
public void setAtributos(List atributos) {
this.atributos = atributos;
}
public String getDescripcion() {
return descripcion;
}
public void setDescripcion(String descripcion) {
this.descripcion = descripcion;
}
}
Then all what im doing on my rest service method is this:
#POST
#Path("/prueba")
#Consumes(MediaType.APPLICATION_JSON)
#Produces(MediaType.APPLICATION_JSON)
public PruebaJSON prueba(String data) {
try {
JSONObject json = new JSONObject(data);
Gson convertir = new GsonBuilder().create();
PruebaJSON pruebaJson = convertir.fromJson(json.toString(), PruebaJSON.class);
return pruebaJson;
} catch (Exception e) {
System.out.println("error " + e);
return null;
}
}
Then in POSTMAN I pass this:
{
"descripcion": "Primera prueba",
"nombre": "Prueba 1",
"atributos": [
"hello",
"kek",
"lul"
]
}
And it works fine, the problem is when I try to do the same by Java, for example:
List atributos = new ArrayList<>();
atributos.add("hello");
atributos.add("kek");
atributos.add("lul");
System.out.println(bus.prueba("Prueba 1", "Primera Prueba", atributos));
bus.prueba just executes the service but then in console I get this error:
14:16:56,567 INFO [stdout] (default task-2) error com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 66 path $.atributos
I did the search of the error and found this:
Gson: Expected begin_array but was STRING
I understand the error but whats the solution?
I can't really control how the JSON builds the arraylist can I?
This is the method prueba in my client:
public String prueba(String nombre, String descripcion, List atributos) {
HashMap map = new HashMap<>();
map.put("nombre", nombre);
map.put("descripcion", descripcion);
map.put("atributos", atributos);
String respuesta = utilidadesRestSeguridad.consumir("prueba", map);
return respuesta;
}
In my client component this is the method that builds the json:
public static JsonObject generateJSON(HashMap map) throws MalformedURLException {
JsonObject json = new JsonObject();
for (Object key : map.keySet()) {
json.addProperty(key.toString(), map.get(key).toString());
}
return json;
}
And thats it guys if you wanna see more code or me to explain something tell me I appreciate any help.
I think maybe the error is in the method generateJSON because of the .toString(), but then how I should handle that case?

Assuming that the line utilidadesRestSeguridad.consumir("prueba", map) ends up calling your generateJSON method downstream, then your issue is likely in the generateJSON() method as you suspect. Basically, you are just adding all elements as strings. If one of the elements in your map is an instance of a List, then you need to call JsonObject#add("atributos", value). For example, you will need something like the following code:
if (map.get(key) instanceof List) {
json.add(key.toString(), map.get(key);
} else {
json.addProperty(key.toString(), map.get(key).toString());
}

As I suspected, the error was in the generateJSON method, needed to add this validation that entpnerd suggested:
public static JsonObject generateJSON(HashMap map) throws MalformedURLException {
JsonObject json = new JsonObject();
for (Object key : map.keySet()) {
if (map.get(key) instanceof List) {
JsonParser parser = new JsonParser();
parser.parse((map.get(key).toString()));
json.add(key.toString(), parser.parse((map.get(key).toString())));
} else {
json.addProperty(key.toString(), map.get(key).toString());
}
}
return json;
}
Notice that I had to use JsonParser, not sure how is it working but at the end that made it work.
Source: How to parse this JSON String with GSON?
Anyways Im gonna try the solution entpnerd is suggesting and post it too.
Here is the implementation of entpnerd suggestion:
public static JsonObject generateJSON(HashMap map) throws MalformedURLException {
JsonObject json = new JsonObject();
for (Object key : map.keySet()) {
if (map.get(key) instanceof List) {
JsonArray jsonArray = new JsonArray();
for (Object object : (ArrayList<Object>) map.get(key)) {
jsonArray.add(object.toString());
}
json.add(key.toString(), jsonArray);
} else {
json.addProperty(key.toString(), map.get(key).toString());
}
}
return json;
}
it works too, you guys decide which one to use, thanks very much.
My only question is, what if the element that is an array, has more arrays inside it, what would you do?

You don't need to get that json value manually, add requestbody annotation to your method parameter
public PruebaJSON prueba(#RequestBody PruebaJSON json){
System.out.println(json);
};

Failed to show the output from json object

I want to parse json from json object and put it on textview. I tried some method but failed. The error:
expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
API SERVICE: Full ver http://139.255.86.189:83/service/api/checklistpertanyaan/1
{
"success": true,
"data": [
{
"idRchecklistpompa": "1",
"nmChecklist": "Membersihkan Body Pompa"
},
{
"idRchecklistpompa": "2",
"nmChecklist": "Membersihkan Kabel Tray Pompa"
},
Harian.java
public class Harian {
#SerializedName("idRchecklistpompa")
#Expose
private String idRchecklistpompa;
#SerializedName("nmChecklist")
#Expose
private String nmChecklist;
public String getIdRchecklistpompa() {
return idRchecklistpompa;
}
public String getNmChecklist() {
return nmChecklist;
}
public void setIdRchecklistpompa(String idRchecklistpompa) {
this.idRchecklistpompa = idRchecklistpompa;
}
public void setNmChecklist(String nmChecklist) {
this.nmChecklist = nmChecklist;
}
}
MainActivity.java
public class HarianActivity extends AppCompatActivity {
private TextView textViewResult;
/*private static String url = "http://139.255.86.189:83/service/api/checklistpertanyaan/1";*/
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_harian);
textViewResult = findViewById(R.id.text_view_result);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://139.255.86.189:83/service/api/")
.addConverterFactory(GsonConverterFactory.create())
.build();
HarianApi harianApi = retrofit.create(HarianApi.class);
Call<List<Harian>> call = harianApi.getHarian();
call.enqueue(new Callback<List<Harian>>() {
#Override
public void onResponse(Call<List<Harian>> call, Response<List<Harian>> response) {
if (!response.isSuccessful()) {
textViewResult.setText("CodeL " + response.code());
return;
}
List<Harian> harians = response.body();
for (Harian harian : harians) {
String content = "";
content += "ID " + harian.getIdRchecklistpompa() + "\n";
content += "NAMA " + harian.getNmChecklist() + "\n";
textViewResult.append(content);
}
}
#Override
public void onFailure(Call<List<Harian>> call, Throwable t) {
textViewResult.setText(t.getMessage());
}
});
}
}

I would expect JSON that encapsulated a List of Harians to look like this:
[
{
"idRchecklistpompa": "1",
"nmChecklist": "Membersihkan Body Pompa"
},
{
"idRchecklistpompa": "2",
"nmChecklist": "Membersihkan Kabel Tray Pompa"
}
]
Instead, yours begins with:
{
"success": true,
"data": [
...
So it isn't correct for your API to return List<Harian>. Instead, your API should return a different class which looks more like:
public class Container {
#SerializedName("success")
private boolean success;
#SerializedName("data")
List<Harian> data;
public static class Harian {
#SerializedName("idRchecklistpompa")
#Expose
private String idRchecklistpompa;
#SerializedName("nmChecklist")
#Expose
private String nmChecklist;
public String getIdRchecklistpompa() {
return idRchecklistpompa;
}
public String getNmChecklist() {
return nmChecklist;
}
public void setIdRchecklistpompa(String idRchecklistpompa) {
this.idRchecklistpompa = idRchecklistpompa;
}
public void setNmChecklist(String nmChecklist) {
this.nmChecklist = nmChecklist;
}
}
}
And have your Retrofit API return Container rather than List<Harian>

Not sure if I understand but, to debug the problem what I would do is:
1.- Check as a String that response is a well formed JSON String.
Log.d(TAG, "My JSON String: " + response.code());
1.5.- Check if that string is a JSONObject or a JSONArray
2.- Probably try to create a JSONObject/JSONArray from that String to see if it triggers an exception.
try {
JSONObject jsonObject = new JSONObject(response.code());
} catch (JSONException e) {
e.printStackTrace();
}
3.- Try to parse the JSONObject but checking for exceptions:
try {
String nmChecklist = jsonObject.getString("nmChecklist");
} catch (JSONException e) {
e.printStackTrace();
}
4.- If you want to avoid exceptions since some objects may or may not have a key or value:
String nmChecklist = jsonObject.has("nmChecklist") && !jsonObject.isNull("nmChecklist") ? jsonObject.getString("nmChecklist") : null;
I hope this helps.

I think there is some problem with your class. The response is different from your pojo class. See json to pojo and create your Model as per the generated pojo.

Response from Retrofit can't get object value

{ "StatusCode": 200, "StatusDescription": "OK", "ErrorMessage":
"", "ErrorDetail": "", "Results": [
{
"Key": "AccessTokens",
"Value": "[{\"Key\":\"XXXXX",
\"Value\":\"BABABA\"},{\"Key\":\"DIDADIDA\",\"Value\":\"YYYYY"
} ]"}]}
This is the response i will get when i success call the API. The datatype of "Results" is List. Can anyone explain for me how to get the "Key" and the "Value".
My Object Classes
public class KeyValueItem {
private String Key;
private String Value;
public String getKey() {
return Key;
}
public void setKey(String key) {
Key = key;
}
public String getValue() {
return Value;
}
public void setValue(String value) {
Value = value;
}
}
Response Class
public class RestServiceResponse {
#SerializedName("StatusCode")
#Expose
public int StatusCode;
public int getStatusCode() {
return StatusCode;
}
#SerializedName("StatusDescription")
#Expose
public String StatusDescription;
public String getStatusDescription() {
return StatusDescription;
}
#SerializedName("ErrorMessage")
#Expose
public String ErrorMessage;
public String getErrorMessage() {
return ErrorMessage;
}
#SerializedName("ErrorDetail")
#Expose
public String ErrorDetail;
public String getErrorDetail() {
return ErrorDetail;
}
#SerializedName("Results")
#Expose
public List<KeyValueItem> Results;
public List<KeyValueItem> getResults() {
return Results;
}
}
Anyone help please =(
Some of my code:
public void onResponse(Call<RestServiceResponse> call, Response<RestServiceResponse> response) {
Log.i("ddsddsadsa", String.valueOf(response.code()));
RestServiceResponse restServiceResponse = response.body();
if(restServiceResponse.getStatusCode() == 200){
List<KeyValueItem> list = response.body().getResults();
JSONArray jsonArray = new JSONArray(list);
try {
JSONObject job = jsonArray.getJSONObject(1);
String testttt = job.getString("Key");
Log.i("dsadsadsadas", testttt);
} catch (JSONException e) {
e.printStackTrace();
}
}

2 things you have to understand first.
Your JSON data is not in valid format. It contains \ (slashes) to escape double quotes in key-value pair. To confirm whether the returned JSON data is valid or not please copy & paste your JSON response into JSON validator and Formatter. Maybe problem in server script.
If you're using GsonConvertorFactory with Retrofit, Retrofit will automatically converts JSON response data to POJO internally. So, you don't need parse it again inside onResponse() method. If you get proper JSON response from server side then use it like below.
public void onResponse(Call<RestServiceResponse> call, Response<RestServiceResponse> response) {
// code....
RestServiceResponse restServiceResponse = response.body();
if (restServiceResponse.getStatusCode() == 200) {
List<KeyValueItem> list = response.body().getResults();
for(int i = 0; i < list.size(); i++) {
KeyValueItem kvi = list.get(i);
// do whatever you want with kvi object
}
}
}

public void onResponse(Call<RestServiceResponse> call, Response<RestServiceResponse> response) {
Log.i("ddsddsadsa", String.valueOf(response.code()));
RestServiceResponse restServiceResponse = response.body();
if(restServiceResponse.getStatusCode() == 200){
List<KeyValueItem> list = response.body().getResults();
for(KeyValueItem keyValueItem : list) {
String key = keyValueItem.getKey();
String value = keyValueItem.getValue();
Log.i("Keykeykey", key);
}
try {
JSONArray jsonArray = new JSONArray(value);
for(int i = 0; i < jsonArray.length();i++) {
JSONObject obj = jsonArray.getJSONObject(i);
String keykey = obj.getString("Key");
String VAlll = obj.getString("Value");
Log.i("c1111",keykey);
Log.i("c222222", VAlll);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}else if(restServiceResponse.getErrorMessage() != null){
builder = new AlertDialog.Builder(LoginActivity.this);
builder.setTitle("Error");
builder.setMessage(restServiceResponse.getErrorMessage());
builder.setPositiveButton("Ok",null);
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
}
OK. Btw. i have try this to get my result. and it works!
To answer those about a invalid JSON format maybe because i have changed the value of the JSON so may have some mistake on it.
Below is the final log i get:
74/com.appandus.user.konnect I/Keykeykey: AccessTokens 07-12
17:14:38.177 6274-6274/com.appandus.user.konnect I/c1111: XXXXX 07-12
17:14:38.177 6274-6274/com.appandus.user.konnect I/c222222: BABABA
07-12 17:14:38.177 6274-6274/com.appandus.user.konnect I/c1111: NS/NH
: DIDAIDA 07-12 17:14:38.177 6274-6274/com.appandus.user.konnect
I/c222222: YYYYYY

Android: How to get JSON object keys from this json:

This is the JSON array:
{
"server_response": [{
"Total": "135",
"Paid": "105",
"Rest": "30"
}]
}
So, how can i get the object names? I want to put them in separate TextView.
Thanks.

Put this out side everything. I mean outside onCreate() and all.
private <T> Iterable<T> iterate(final Iterator<T> i){
return new Iterable<T>() {
#Override
public Iterator<T> iterator() {
return i;
}
};
}
For getting the names of objects :
try
{
JSONObject jsonObject = new JSONObject("{" +"\"server_response\": [{" +"\"Total\": \"135\"," +"\"Paid\": \"105\"," +"\"Rest\": \"30\"" +"}]"+"}";);
JSONArray jsonArray = jsonObject.getJSONArray("server_response");
JSONObject object = jsonArray.getJSONObject(0);
for (String key : iterate(object.keys()))
{
// here key will be containing your OBJECT NAME YOU CAN SET IT IN TEXTVIEW.
Toast.makeText(HomeActivity.this, ""+key, Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
Hope this helps :)

My suggestion:
Go to this website:
Json to pojo
Get your pojo classes and then use them in Android.
All you need to do is to use Gson.fromGson(params here).
One of your params is the class that you created using the online schema.

You can use jackson ObjectMapper to do this.
public class ServerResponse {
#JsonProperty("Total")
private String total;
#JsonProperty("Paid")
private String paid;
#JsonProperty("Rest")
private String rest;
//getters and setters
//toString()
}
//Now convert json into ServerResponse object
ObjectMapper mapper = new ObjectMapper();
TypeReference<ServerResponse> serverResponse = new TypeReference<ServerResponse>() { };
Object object = mapper.readValue(jsonString, serverResponse);
if (object instanceof ServerResponse) {
return (ServerResponse) object;
}

JSONObject jsonObject = new JSONObject("Your JSON");
int Total = jsonObject.getJSONArray("server_response").getJSONObject(0).getInt("Total");
int Paid = jsonObject.getJSONArray("server_response").getJSONObject(0).getInt("Paid");
int Rest = jsonObject.getJSONArray("server_response").getJSONObject(0).getInt("Rest");

Iterating through json array with appended json string in android after json as response from url using volley

Hi i am trying to iterate through a json string that looks like this:
{
"vendor":[
{
"vendor_name":"Tapan Moharana",
"vendor_description":"",
"vendor_slug":"tapan",
"vendor_logo":null,
"contact_number":null
}
],
"products":
{
"25":
{
"name":"Massage",
"price":"5000.0000",
"image":"http:\/\/carrottech.com\/lcart\/media\/catalog\/product\/cache\/1\/image\/150x\/9df78eab33525d08d6e5fb8d27136e95\/2\/9\/29660571-beauty-spa-woman-portrait-beautiful-girl-touching-her-face.jpg"
},
"26":
{
"name":"Chicken Chilly",
"price":"234.0000",
"image":"http:\/\/carrottech.com\/lcart\/media\/catalog\/product\/cache\/1\/image\/150x\/9df78eab33525d08d6e5fb8d27136e95\/c\/h\/cheicken.jpg"
},
"27":
{
"name":"Chicken Biryani",
"price":"500.0000",
"image":"http:\/\/carrottech.com\/lcart\/media\/catalog\/product\/cache\/1\/image\/150x\/9df78eab33525d08d6e5fb8d27136e95\/placeholder\/default\/image_1.jpg"
}
}
}
here is a better view of the json string:
I am iterating through the vendor array of this json string using this code:
JSONObject jsono = new JSONObject(response);
JSONArray children = jsono.getJSONArray("vendor");
for (int i = 0; i <children.length(); i++) {
JSONObject jsonData = children.getJSONObject(i);
System.out.print(jsonData.getString("vendor_name") + "<----");
// String vendorThumbNailURL=jsonData.getString("")
//jvendorImageURL.setImageUrl(local, mImageLoader);
vendorLogo=vendorLogo+jsonData.getString("vendor_logo").trim();
jvendorImageURL.setImageUrl(vendorLogo, mImageLoader);
jvendorName.setText(jsonData.getString("vendor_name"));
jvendorAbout.setText(jsonData.getString("vendor_description"));
jvendorContact.setText(jsonData.getString("contact_number"));
}
but I dont know how to get data from the "products" object please help me how do i set my json objects to iterate through "products"
when i try to change the format of the array so that both products and vendor are a separate json array i still get the above json format..
this is what i am doing
$resp_array['vendor'] = $info;
$resp_array['products'] = $vendorProductsInfo;
$resp_array = json_encode($resp_array);
print_r($resp_array);
please help me with this
MODIFIED QUESTION:
I have modified my web response like this:
[{"entity_id":24,"product_name":"Burger","product_image_url":"\/b\/u\/burger_large.jpg","price":"234.0000","category_id":59},{"entity_id":27,"product_name":"Chicken Biryani","product_image_url":"\/b\/i\/biryani.jpg","price":"500.0000","category_id":59},{"entity_id":31,"product_name":"Pizza","product_image_url":"\/p\/i\/pizza_png7143_1.png","price":"125.0000","category_id":59}]
and the code:
JSONArray children = jsono.getJSONArray("vendor");
for (int i = 0; i <children.length(); i++) {
JSONObject jsonData = children.getJSONObject(i);
System.out.print(jsonData.getString("vendor_name") + "<----");
// String vendorThumbNailURL=jsonData.getString("")
//jvendorImageURL.setImageUrl(local, mImageLoader);
vendorLogo=vendorLogo+jsonData.getString("vendor_logo").trim();
jvendorImageURL.setImageUrl(vendorLogo, mImageLoader);
jvendorName.setText(jsonData.getString("vendor_name"));
jvendorAbout.setText(jsonData.getString("vendor_description"));
jvendorContact.setText(jsonData.getString("contact_number"));
System.out.print(jsonData.getString("products") + "<----");
}
JSONObject jsono1 = new JSONObject(response);
JSONArray childrenProducts = jsono1.getJSONArray("products");
for(int i=0;i<childrenProducts.length();i++){
JSONObject jsonData = childrenProducts.getJSONObject(i);
System.out.print(jsonData.getString("name") + "<----dd");
}
but still the products part is not working... please help

Here is the working solution: Using GOOGLE GSON (Open source jar)
import java.io.IOException;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
public class JsonToJava {
public static void main(String[] args) throws IOException {
try{
String json = "<YOUR_JSON>";
Gson gson = new GsonBuilder().create();
VendorInfo vInfo = gson.fromJson(json, VendorInfo.class);
System.out.println(vInfo.getVendorName());
} catch(Exception ex) {
ex.printStackTrace();
}
}
}
Create classes for Vendor and Product
public class Vendor {
public String vendor_name;
public String vendor_description;
public String vendor_slug;
public String vendor_logo;
public String contact_number;
public String getName() {
return vendor_name;
}
}
public class Product {
public String name;
public long price;
public String image;
public String getName() {
return name;
}
}
VendorInfo is the JSON object form:
import java.util.Map;
public class VendorInfo {
public Vendor[] vendor;
public Map<Integer, Product> products;
public String getVendorName() {
return vendor[0].getName();
}
public Product getProduct() {
System.out.println(products.size());
return products.get(25);
}
}
You can add your getters for Vendor, Product and VendorInfo. You are done! You will get all the data.
Output of JsonToJava:
Tapan Moharana

To get your products data , you need to use Iterator
JSONObject jProducts = jsonObject
.optJSONObject("products");
try {
if (jProducts
.length() > 0) {
Iterator<String> p_keys = jProducts
.keys();
while (p_keys
.hasNext()) {
String keyProduct = p_keys
.next();
JSONObject jP = jProducts
.optJSONObject(keyProduct);
if (jP != null) {
Log.e("Products",
jP.toString());
}
}
}
} catch (Exception e) { // TODO:
// handle
// exception
}

you can try with this
JSONObject jsono = null;
try {
jsono = new JSONObject(response);
JSONObject productObject = jsono.getJSONObject("products");
Iterator<String> keys = productObject.keys();
while (keys.hasNext())
{
// get the key
String key = keys.next();
// get the value
JSONObject value = productObject.getJSONObject(key);
//get seprate objects
String name = value.getString("name");
String image = value.getString("image");
Log.i(TAG,name+"-"+image);
}
}
catch (JSONException e) {
e.printStackTrace();
}

Try this :
JSONObject productObject = jsono.getJSONObject("products");
JSONObject json_25 = productObject getJSONObject("25");
String name_25= json_25.getString("name");
String price_25= json_25.getString("price");
String image_25= json_25.getString("image");
JSONObject json_26 = productObject getJSONObject("26");
String name_26= json_26.getString("name");
String price_26= json_26.getString("price");
String image_26= json_26.getString("image");
JSONObject json_27 = productObject getJSONObject("27");
String name_27= json_27.getString("name");
String price_27= json_27.getString("price");
String image_27= json_27.getString("image");