I have a json string returning:
[{"TRAIN_JOURNEY_STAFF[],"ID":15,"EMAIL_ADDRESS":"jk#connectedrail.com","PASSWORD":"test","FIRST_NAME":"Joe","LAST_NAME":"Kevin","DATE_OF_BIRTH":"1996-04-20T00:00:00","GENDER":"Male","STAFF_ROLE":"Conductor","PHOTO":null},{new record..}]
There are several records here, I can't find a way to convert this json string to individual objects. I'm using the following to read in the data:
StringBuffer response;
try (BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()))) {
String inputLine;
response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
}
System.out.print(response.toString());
}
I've tried the simple json libary but the parser mixes up the string, Which is not ideal as I need to output the data to rows object by object to jtables.
Any help would be appreciated.
Solved it with the below with GSON. Many thanks everyone!
JsonElement jelement = new JsonParser().parse(response.toString());
JsonArray jarray = jelement.getAsJsonArray();
JsonObject jobject = jarray.get(0).getAsJsonObject();
System.out.println(jobject.get("FIRST_NAME"));
You can use something like this:
public class ObjectSerializer {
private static ObjectMapper objectMapper;
#Autowired
public ObjectSerializer(ObjectMapper objectMapper) {
ObjectSerializer.objectMapper = objectMapper;
}
public static <T> T getObject(Object obj, Class<T> class1) {
String jsonObj = "";
T userDto = null;
try {
jsonObj = objectMapper.writeValueAsString(obj);
userDto = (T) objectMapper.readValue(jsonObj, class1);
System.out.println(jsonObj);
} catch (JsonProcessingException jpe) {
} catch (IOException e) {
e.printStackTrace();
}
return userDto;
}
Pass your JSON Object to this method alogn with class name and it will set the JSON data to that respective class.
Note:
Class must have the same variables as in the JSON that you want to map with it.
Using org.json library:
JSONObject jsonObj = new JSONObject("{\"phonetype\":\"N95\",\"cat\":\"WP\"}");
see this
You can use Jackson to convert JSON to an object.Include the dependency :
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.6.3</version>
</dependency>
Then make a POJO class to store the JSON .The pojo class should reflect the json string structure and should have appropriate fields to map the values(Here in sample code Staff.class is a pojo class).Then, by using ObjectMapper class you can convert the JSON string to a java object as follows :
StringBuffer response;
try (BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()))) {
String inputLine;
response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
}
System.out.print(response.toString());
ObjectMapper mapper = new ObjectMapper();
//JSON from file to Object
Staff obj = mapper.readValue(new File("c:\\file.json"), Staff.class);
//JSON from String to Object
Staff obj = mapper.readValue(response.toString(), Staff.class);
Another simple method to read a JSON string and convert it into an object is :
JSON String:
{
"lastName":"Smith",
"address":{
"streetAddress":"21 2nd Street",
"city":"New York",
"state":"NY",
"postalCode":10021
},
"age":25,
"phoneNumbers":[
{
"type":"home", "number":"212 555-1234"
},
{
"type":"fax", "number":"212 555-1234"
}
],
"firstName":"John"
}
public class JSONReadExample
{
public static void main(String[] args) throws Exception
{
// parsing file "JSONExample.json"
Object obj = new JSONParser().parse(new FileReader("JSONExample.json"));
// typecasting obj to JSONObject
JSONObject jo = (JSONObject) obj;
// getting firstName and lastName
String firstName = (String) jo.get("firstName");
String lastName = (String) jo.get("lastName");
System.out.println(firstName);
System.out.println(lastName);
// getting age
long age = (long) jo.get("age");
System.out.println(age);
// getting address
Map address = ((Map)jo.get("address"));
// iterating address Map
Iterator<Map.Entry> itr1 = address.entrySet().iterator();
while (itr1.hasNext()) {
Map.Entry pair = itr1.next();
System.out.println(pair.getKey() + " : " + pair.getValue());
}
// getting phoneNumbers
JSONArray ja = (JSONArray) jo.get("phoneNumbers");
// iterating phoneNumbers
Iterator itr2 = ja.iterator();
while (itr2.hasNext())
{
itr1 = ((Map) itr2.next()).entrySet().iterator();
while (itr1.hasNext()) {
Map.Entry pair = itr1.next();
System.out.println(pair.getKey() + " : " + pair.getValue());
}
}
}
}
For reference:
https://www.geeksforgeeks.org/parse-json-java/
https://www.mkyong.com/java/jackson-2-convert-java-object-to-from-json/
What you have basically is this :
[
{
"TRAIN_JOURNEY_STAFF":[
],
"ID":15,
"EMAIL_ADDRESS":"jk#connectedrail.com",
"PASSWORD":"test",
"FIRST_NAME":"Joe",
"LAST_NAME":"Kevin",
"DATE_OF_BIRTH":"1996-04-20T00:00:00",
"GENDER":"Male",
"STAFF_ROLE":"Conductor",
"PHOTO":null
},
{
}
]
You can use JSON constructor to serialize this array to an Array of JSONObjects.
Try looking for JSONObject and JSONArray classes in Java.
The constructor basically takes the stringified JSON (which you already have).
Related
The problem I am facing is that I want to ser/des null values when only it comes to non top-level attributes, and I have no idea how to achieve that. So let's say I have a User class:
Class User {
String name;
int id;
Address address;
}
And an Address class:
Class Address{
String street;
String city;
String country;
}
Right now, I can use below Gson instance to ser/des null values:
Gson gson = new GsonBuilder().serializeNulls().create();
Address address = new Address(null, "New York", "US");
User user = new User("Adam", 123, address);
String userJson = gson.toJson(user);
Output is:
{
"name": "Adam",
"id": 123,
"address": {
"street": null,
"city": "New York",
"country": "US"
}
}
However, I do NOT want to ser/des nulls when it comes to top-level attributes of User. For example for below User:
User user = new User("Adam", 123, null);
I want to have an output as below and without address field:
{
"name": "Adam",
"id": 123
}
I am now trying to use a customized serializer to hardcode every top-level attributes and remove them if they are null:
public class SerializerForUser implements JsonSerializer<ConfigSnapshot> {
#Override
public JsonElement serialize(User user, Type type, JsonSerializationContext jsc) {
Gson gson = new GsonBuilder().serializeNulls().create();
JsonObject jsonObject = gson.toJsonTree(user).getAsJsonObject();
if (user.getAddress() == null) {
jsonObject.remove("address");
}
// if... (same with other top-level attributes)
return jsonObject;
}
}
Gson gson = new GsonBuilder().serializeNulls().registerTypeAdapter(User.class, new SerializerForUser()).create();
But somehow it is not working, I will still get below output when for example address is null:
{
"name": "Adam",
"id": 123,
"address: null
}
can anyone give me some hints on what did I wrong here? Or it would be perfect if anyone can tell me if there is more straight forward/general way to achieve this(since I also want to use the same gson instance to ser/des other objects)?
Any comments are appreciated.
Because you are using
Gson gson = new GsonBuilder().serializeNulls().create();
which shows null value.
To skip showing null, let's try
Gson gson = new Gson();
You can test here
public static void main(String[] args) {
Gson yourGson = new GsonBuilder().serializeNulls().create(); // this is how you create your Gson object, which shows null value
Address address = new Address(null, "New York", "US");
User user = new User("Adam", 123, address);
String userJson = yourGson.toJson(user);
System.out.println(userJson);
Gson newGson = new Gson(); // with this one, it doesn't show value
System.out.println(newGson.toJson(user));
}
Update
I have tried to override the method serialize with a few times and it failed until I try #5
public class UserCustomSerializer implements JsonSerializer<User> {
#Override
public JsonElement serialize(User src, Type typeOfSrc, JsonSerializationContext context) {
JsonObject obj = new JsonObject();
if (src.name != null) {
obj.addProperty("name", src.name);
}
obj.addProperty("id", src.id);
if (src.address != null) {
// try #1
//JsonObject addressJsonObj = new JsonObject();
//addressJsonObj.addProperty("street", src.address.street != null ? src.address.street : null);
//addressJsonObj.addProperty("city", src.address.city != null ? src.address.city : null);
//addressJsonObj.addProperty("country", src.address.country != null ? src.address.country : null);
//obj.add("address", addressJsonObj);
// try #2
//Gson gson = new GsonBuilder().serializeNulls().create();
//JsonElement jsonElement = gson.toJsonTree(src.address);
//obj.add("address", jsonElement);
// try #3
//Gson gson2 = new GsonBuilder().serializeNulls().create();
//obj.addProperty("address", gson2.toJson(src.address));
// try #4
//Gson gson = new GsonBuilder().serializeNulls().create();
//JsonObject jsonObject = gson.toJsonTree(src.address).getAsJsonObject();
//obj.add("address", jsonObject);
// try #5
JsonObject addressJsonObj = new JsonObject();
addressJsonObj.addProperty("street", src.address.street != null ? src.address.street : "null");
addressJsonObj.addProperty("city", src.address.city != null ? src.address.city : "null");
addressJsonObj.addProperty("country", src.address.country != null ? src.address.country : "null");
obj.add("address", addressJsonObj);
}
return obj;
}
}
For try #3, I built the incorrect String.
For try #1, #2 and #4, I have the problem with the null value. I searched and found the reason and also the suggestion here
In a JSON "object" (aka dictionary), there are two ways to represent absent values: Either have no key/value pair at all, or have a key with the JSON value null.
So you either use .add with a proper value what will get translated to null when you build the JSON, or you don't have the .add call.
And my #5 approach is to check if the child node is null, I just add the string "null" literally and then I replace it when I build the json string
private String parseToGson(User user){
Gson gson = new GsonBuilder().registerTypeAdapter(User.class, new UserCustomSerializer()).create();
return gson.toJson(user).replace("\"null\"", "null");
}
Here are some test cases I defined
#Test
public void children_attribute_is_null() throws Exception {
String expected = "{\"name\":\"Adam\","
+ "\"id\":123,"
+ "\"address\":{"
+ "\""+ "street\":null,"
+ "\"city\":\"New York\","
+ "\"country\":\"US"
+ "\"}"
+ "}";
Address address = new Address(null, "New York", "US");
User user = new User("Adam", 123, address);
assertEquals(expected, parseToGson(user));
Gson g = new Gson();
User usr = g.fromJson( parseToGson(user), User.class);
assertEquals("Adam", usr.name);
assertEquals(123, usr.id);
assertEquals(null, usr.address.street);
assertEquals("New York", usr.address.city);
assertEquals("US", usr.address.country);
}
#Test
public void parent_attribute_is_null() throws Exception {
String expected = "{\"name\":\"Adam\","
+ "\"id\":123" + "}";
User user = new User("Adam", 123, null);
assertEquals(expected, parseToGson(user));
Gson g = new Gson();
User usr = g.fromJson( parseToGson(user), User.class);
assertEquals("Adam", usr.name);
assertEquals(123, usr.id);
assertEquals(null, usr.address);
}
#Test
public void parent_attribute_and_children_attribute_are_null() throws Exception {
String expected = "{\"id\":123,"
+ "\"address\":{"
+ "\"street\":null,"
+ "\"city\":\"New York\","
+ "\"country\":\"US"
+ "\"}"
+ "}";
Address address = new Address(null, "New York", "US");
User user = new User(null, 123, address);
assertEquals(expected, parseToGson(user));
Gson g = new Gson();
User usr = g.fromJson( parseToGson(user), User.class);
assertEquals(null, usr.name);
assertEquals(123, usr.id);
assertEquals(null, usr.address.street);
assertEquals("New York", usr.address.city);
assertEquals("US", usr.address.country);
}
Update #2
Since the previous version is not a generic one, I would like to update the answer.
For generic, I created MyCustomSerializer as following
public class MyCustomSerializer<T> implements JsonSerializer<T> {
private final Class<T> type;
public MyCustomSerializer(Class<T> type) {
this.type = type;
}
public Class<T> getMyType() {
return this.type;
}
#Override
public JsonElement serialize(T src, Type typeOfSrc, JsonSerializationContext context) {
JsonObject obj = new JsonObject();
try {
Field[] declaredFields = this.type.getDeclaredFields();
for (Field field : declaredFields) {
Object object = field.get(src);
if (object != null) {
// Here, we check for 4 types of JsonObject.addProperty
if (object instanceof String) {
obj.addProperty(field.getName(), (String) object);
continue;
}
if (object instanceof Number) {
obj.addProperty(field.getName(), (Number) object);
continue;
}
if (object instanceof Boolean) {
obj.addProperty(field.getName(), (Boolean) object);
continue;
}
if (object instanceof Character) {
obj.addProperty(field.getName(), (Character) object);
continue;
}
// This is where we check for other types
// The idea is if it is an object, we need to care its child object as well, so parse it into json string and replace the null value.
Gson gson = new GsonBuilder().serializeNulls().create();
String json = gson.toJson(object);
json = json.replace("null", "\"null\""); // We have to build the string first, then replace it with our special keys. In this case, I use the string "null"
JsonObject convertedObject = new Gson().fromJson(json, JsonObject.class); // Then convert it back to json object
obj.add(field.getName(), convertedObject);
}
}
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return obj;
}
}
The main idea is still the same as previous version but I made it to a generic one.
I also added some additional properties to test for the string this code builds with the results
{
"id":123,
"address":{
"street":null,
"city":"New York",
"country":"US",
"info":{
"zipcode":null,
"address2":"stackoverflow",
"workPlaceAddress":{
"street":null,
"companyName":"google"
}
}
}
}
To call this, we need to do
private String parseToGson(User user) {
Gson gson = new GsonBuilder().registerTypeAdapter(User.class, new MyCustomSerializer<>(User.class)).create();
return gson.toJson(user).replace("\"null\"", "null");
}
Update #3
Since you still concern about your solution, I tried to adapt it as well
public class YourSerializer <T> implements JsonSerializer<T>{
private final Class<T> type;
public YourSerializer(Class<T> type) {
this.type = type;
}
public Class<T> getMyType() {
return this.type;
}
#Override
public JsonElement serialize(T src, Type typeOfSrc, JsonSerializationContext context) {
Gson gson = new GsonBuilder().serializeNulls().create();
JsonObject jsonObject = gson.toJsonTree(src).getAsJsonObject();
Field[] declaredFields = this.type.getDeclaredFields();
for (Field field : declaredFields) {
try {
if(field.get(src) == null) {
jsonObject.remove(field.getName());
}
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
return jsonObject;
}
}
The reason is you used serializeNulls() incorrectly which makes your output is incorrect. To correct it, you should registerTypeAdapter first to create your custom json, then you call serializeNulls
private String parseToGson(User user) {
Gson gson = new GsonBuilder().registerTypeAdapter(User.class, new YourSerializer<>(User.class)).serializeNulls().create();
return gson.toJson(user);
}
I tested and got the same result with update#2
{
"id":123,
"address":{
"street":null,
"city":"New York",
"country":"US",
"info":{
"zipcode":null,
"address2":"aaa",
"workPlaceAddress":{
"street":null,
"companyName":"google"
}
}
}
}
I have a json as below. I want to get mobile_number from this jsonObject.
json:-
{"id": "ABCD", "report": { "data": { "phone": { "mobile_number": 9876543210, "active": "Y", "content": null } } } }
I am doing it like this and it works fine but can someone help me with any other approach for it without getting every key.
JSONObject jsonObject = new JSONObject(json);
JSONObject report = getJSONObjectFromJson(jsonObject, "report");
JSONObject data = getJSONObjectFromJson(jsonObject, "data");
JSONObject phone = getJSONObjectFromJson(data, "phone");
long mobileNumber = getLongFromJson(phone, "mobile_number");
private Long getLongFromJson(JSONObject object, String key){
return (object !=null && object.has(key)) ? object.getLong(key) : null;
}
private JSONObject getJSONObjectFromJson(JSONObject object, String key){
return (object !=null && object.has(key)) ? object.getJSONObject(key) : null;
}
I've just dealing with the similar issue and decided to use JsonPath like this:
final DocumentContext jsonContext = JsonPath.parse(jsonString);
final Object read = jsonContext.read("$['report']['data']['phone']['mobile_number']");
You can use Jackson ObjectMapper.
try {
ObjectMapper mapper = new ObjectMapper();
String jsonString = "{\"id\": \"ABCD\", \"report\": { \"data\": { \"phone\": { \"mobile_number\": 9876543210, \"active\": \"Y\", \"content\": null } } } }";
JsonNode rootNode = mapper.readTree(jsonString);
JsonNode mobileNumber = rootNode.path("report").path("data").path("phone").path("mobile_number");
System.out.println("Mobile Number: " + mobileNumber.longValue());
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
So there are lot of ways to do it but everything leads eventually to traversing the tree.
So to conclude all the approaches,
1. **Convert string to JsonObject and traverse.**
JSONObject jsonObject = new JSONObject(json);
JSONObject report = getJSONObjectFromJson(jsonObject, "report");
JSONObject data = getJSONObjectFromJson(jsonObject, "data");
JSONObject phone = getJSONObjectFromJson(data, "phone");
long mobileNumber = getLongFromJson(phone, "mobile_number");
private Long getLongFromJson(JSONObject object, String key){
return (object !=null && object.has(key)) ? object.getLong(key) : null;
}
private JSONObject getJSONObjectFromJson(JSONObject object, String key){
return (object !=null && object.has(key)) ? object.getJSONObject(key) : null;
}
2. **Using jackson objectMapper to get the JsonNode and then traverse.**
ObjectMapper mapper = new ObjectMapper();
JsonNode jsonNode= mapper.readTree(json);
JsonNode mobileNumber = jsonNode.path("report").path("data").path("phone").path("mobile_number");
3. **Using gson jsonmapper to convert to map and then iterate the map.**
Gson gson = new Gson();
Map map = gson.fromJson(json, Map.class);
jsonObject.getJSONObject("x").getJSONObject("Y").getJSONObject("z");
Another route would be to leverage the ObjectMapper.
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");
I convert JSONObject in string for parse it in JsonNode with jackson but i have a List in my JSONObject and when i parse it with a ObjectMapper i get this :
["{Property1 : value1, Property2 : value2}"]
And i can't call myJsonNodeObject.get(i).get("Property1") this is my problem.
I have tried to cast my List in JSONArray in my JSONObject but don't work.
resultAsJSONObject = new JSONObject();
resultAsJSONObject.put("Label", getMetricStatisticsResult.getLabel());
resultAsJSONObject.put("Datapoints", getMetricStatisticsResult.getDatapoints());
resultAsJSONObject.put("fromDate", fromDate.getTimeInMillis());
resultAsJSONObject.put("toDate", toDate.getTimeInMillis());
resultAsJSONObject.put("error", "");
resultAsString = resultAsJSONObject.toString();
mapper.readValue(resultAsString, MetricsData.class);
Assuming that you have a JSON string which you just want to change. Then you can use Jackson to parse it as a ObjecNode and then modify it. Here is an example:
public class JacksonModifyJson {
static final String JSON = "{\"name\":\"Bob\", \"age\":13}";
public static void main(String[] args) throws IOException {
final ObjectMapper mapper = new ObjectMapper();
final ObjectNode jsonNode = mapper.readValue(JSON, ObjectNode.class);
jsonNode.put("url", "example.com");
System.out.println(mapper.writeValueAsString(jsonNode));
}
}
Output:
{"name":"Bob","age":13,"url":"example.com"}
THis method is really easy and works too
try {
JSONObject jsonObject = new JSONObject(THESTRINGHERE);
String[] names = JSONObject.getNames(jsonObject);
JSONArray jsonArray = jsonObject.toJSONArray(new JSONArray(names));
ArrayList<String> listdata = new ArrayList<String>();
JSONArray jArray = (JSONArray)jsonArray;
if (jArray != null) {
for (int i=0;i<jArray.length();i++){
listdata.add(jArray.get(i).toString());
}
}
// System.out.println(listdata);
} catch (Exception e) {
System.out.println(e.getMessage());
}
I would like to append JSON object to existing JSON array to get data structure like this.
"results":[
{
"lat":"value",
"lon":"value"
},
{
"lat":"value",
"lon":"value"
}
]
I'm trying to do it using the code in example, but unfortunately whole object is overriden everytime.
Log.i(AppHelper.APP_LOG_NAMESPACE, "POSITIONS AVAILABLE " + jsonDataString);
AppHelper helper = new AppHelper(ctx);
JSONObject mainObject = new JSONObject(jsonDataString);
JSONObject valuesObject = new JSONObject();
JSONArray list = new JSONArray();
//putv given values to the JSON
valuesObject.put("lat", lat.toString());
valuesObject.put("lon", lon.toString());
valuesObject.put("city", city);
valuesObject.put("street", street);
valuesObject.put("date", helper.getActualDateTime());
valuesObject.put("time", helper.getActualDateTime());
list.put(valuesObject);
//mainObject.put("values", list);
mainObject.accumulate("values", list);
saveJsonData(ctx, mainObject.toString(),"positions");
How it should be right?
Put and accumulate everytime rewrite all previous values, but i would like to append this object:
{
"lat":"value",
"lon":"value"
},
Into results parent.
BTW: I would like to do it without GSON.
Thanks for any help..
There isnt any problem with your code. It does append
String jsonDataString = "{\"results\":[{\"lat\":\"value\",\"lon\":\"value\" }, { \"lat\":\"value\", \"lon\":\"value\"}]}";
JSONObject mainObject = new JSONObject(jsonDataString);
JSONObject valuesObject = new JSONObject();
JSONArray list = new JSONArray();
valuesObject.put("lat", "newValue");
valuesObject.put("lon", "newValue");
valuesObject.put("city", "newValue");
valuesObject.put("street", "newValue");
valuesObject.put("date", "newValue");
valuesObject.put("time", "newValue");
list.put(valuesObject);
mainObject.accumulate("values", list);
System.out.println(mainObject);
This prints {"values":[[{"date":"newValue","city":"newValue","street":"newValue","lon":"newValue","time":"newValue","lat":"newValue"}]],"results":[{"lon":"value","lat":"value"},{"lon":"value","lat":"value"}]}.
Isnt this what you are expecting?
With gson you can do like
import com.google.gson.Gson;
import com.google.gson.JsonObject;
public class AddJson {
public static void main(String[] args) {
String json = "{\"results\":[{\"lat\":\"value\",\"lon\":\"value\" }, { \"lat\":\"value\", \"lon\":\"value\"}]}";
Gson gson = new Gson();
JsonObject inputObj = gson.fromJson(json, JsonObject.class);
JsonObject newObject = new JsonObject() ;
newObject.addProperty("lat", "newValue");
newObject.addProperty("lon", "newValue");
inputObj.get("results").getAsJsonArray().add(newObject);
System.out.println(inputObj);
}
}
Simple Approach
String jsonData = "{\"results\":[{\"lat\":\"value\",\"lon\":\"value\" }]}";
System.out.println(jsonData);
try {
JSONArray result = new JSONObject(jsonData).getJSONArray("results");
result.getJSONObject(0).put("city","Singapore");
jsonData = "{\"results\":"+result.toString()+"}";
System.out.println(jsonData);
} catch (JSONException e) {
e.printStackTrace();
}
OutPut Before Appending
{"results":[{"lat":"value","lon":"value" }]}
OutPut After Appending
{"results":[{"lon":"value","lat":"value","city":"Singapore"}]}
If you want to add new value to an Object you can try the below as well
Before:
{
"Name": "EnCoMa",
"Manager": "Abhishek Kasetty"
}
code :
JsonFactory factory = new JsonFactory();
ObjectMapper mapper = new ObjectMapper(factory);
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
String json = ow.writeValueAsString(TheObjectToWhichYouWantToAddNewValue);
ObjectNode node = (ObjectNode) mapper.readTree(json);
node.putPOJO("new Key","new value")
after:
{
"Name": "EnCoMa",
"Manager": "Abhishek Kasetty",
"new Key": "new value"
}