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How to merge two JSON string

I have two JSON strings, I want to merge these two response string into a single one. Is there any way to merge these two JSON string using java ?
String str1 = "{
"data" : {
"values" : {
"name" : "kiran",
"age" : "24"
}
}
}"
String str2 = "{
"data" : {
"values" : {
"name" : "Mamu",
"age" : "26"
}
}
}"
I wnat to merge these two JSON string as follows
String mergeResult = "{
"data" : {
"values" : [
{
"name" : "kiran",
"age" : "24"
},
{
"name" : "Manu",
"age" : "26"
}
]
}
}"

From your example JSON it looks like there can be many more input objects than two, so I'd use a JSON to JSON transform via JOLT library (https://github.com/bazaarvoice/jolt) as follows:
Form a JSON array of all the input {"data" : ...} objects (either by collecting the original objects and putting them in a List before serialization or just manually by concatenating their JSONs with square brackets):
[
{
"data": {
"values": {
"name": "kiran",
"age": "24"
}
}
},
{
"data": {
"values": {
"name": "Mamu",
"age": "26"
}
}
}
]
Use the JOLT spec:
[
{
"operation": "shift",
"spec": {
"*": {
"data": {
"values": {
"#": "data.values[]"
}
}
}
}
}
]
The resulting JSON:
{
"data" : {
"values" : [ {
"name" : "kiran",
"age" : "24"
}, {
"name" : "Mamu",
"age" : "26"
} ]
}
}
You can test or modify the spec yourself at http://jolt-demo.appspot.com before using it in your application.
Here's what Java side might look like:
Resource transformationSpec = ...
String inputJson = ...
List<Object> specs = JsonUtils.jsonToList(transformationSpec.getInputStream());
Chainr chainr = Chainr.fromSpec(specs);
Object inputObject = JsonUtils.jsonToObject(inputJson);
Object transformedObject = chainr.transform(inputObject);
String transformedJson = JsonUtils.toJsonString(transformedObject);

Library Josson & Jossons has concatenate operation to combine array from datasets.
https://github.com/octomix/josson
Jossons jossons = new Jossons();
jossons.putDataset("resp1", Josson.fromJsonString(
"{" +
" \"data\": {" +
" \"values\": {" +
" \"name\": \"kiran\"," +
" \"age\": \"24\"" +
" }" +
" }" +
"}"));
jossons.putDataset("resp2", Josson.fromJsonString(
"{" +
" \"data\": {" +
" \"values\": {" +
" \"name\": \"Mamu\"," +
" \"age\": \"26\"" +
" }" +
" }" +
"}"));
JsonNode mergeValues = jossons.evaluateQuery(
"resp1->data.toArray() <+< resp2->data.toArray()");
System.out.println(mergeValues.toPrettyString());
JsonNode mergeResult = Josson.create(mergeValues).getNode(
"toObject('values').toObject('data')");
System.out.println(mergeResult.toPrettyString());
mergeValues
[ {
"name" : "kiran",
"age" : "24"
}, {
"name" : "Mamu",
"age" : "26"
} ]
mergeResult
{
"data" : {
"values" : [ {
"name" : "kiran",
"age" : "24"
}, {
"name" : "Mamu",
"age" : "26"
} ]
}
}

May be not the most efficient solution but very simple one would be to parse each String into a Map (or specific POJO if you have one) and merge them as maps, and than serialize back into Json String. To parse a json string to map or a specific POJO you can use Jackson library - method readValue() of ObjectMapper Or Gson library. Also, I wrote my own simple wrapper over Jackson library that simplifies the use. Class JsonUtils is available as part of MgntUtils library (written and maintained by me). This class just has the methods that allow you to parse and de-serialize from/to Json String from/to a class instance. So your code could be as follows:
public String mergeJsonStrings(String str1, Str2) throws IOException {
Map<String, Object> map1 = convertJsonStringToMap(str1);
Map<String, Object> map2 = convertJsonStringToMap(str2);
Map<String, Object> dataMap1 = (Map<String, Object>)map1.get("data");
Map<String, Object> valuesMap1 = (Map<String, Object>)dataMap1.get("values");
Map<String, Object> dataMap2 = (Map<String, Object>)map2.get("data");
Map<String, Object> valuesMap2 = (Map<String, Object>)dataMap2.get("values");
valuesMap1.putAll(valuesMap2);
return convertMapToJsonString(map1);
}
Map<String, Object> convertJsonStringToMap(String str) throws IOException {
return JsonUtils.readObjectFromJsonString(str, Map.class);
}
Strong convertMapToJsonString(Map<String,Object> map) throws JsonProcessingException{
return JsonUtils.writeObjectToJsonString(map);
}
This example uses MgntUtils library to parse and serialize JSON but of course you can use Jackson, Gson or any other library you want. MgntUtils library available as Maven artifact and on Github (including source code and Javadoc)

Java - How to iterate over a list of hashmap?

I have a following response from a HTTP call which looks like this...
[{"id": 1, "name" : abc, "above50" : true} , {"id": 2, "name" : "xyc", "above50" : false, "kids" : "yes"} ]
I need to iterate through this list and find if there is a key called kids and if there is the key kids, i need to store the value . How do i do it in java?

First you need to parse the json string - it's a list of objects. If you don't have classes to match those objects, by default they can be represented as Map<String, Object>. Then you need to iterate the list, and for every object in it, you have to iterate the entries in the object. If the key matches, store it.
//parse json string with whatever parser you like
List<Map<String, Object>> list = ...;
//iterate every object in the list
for (Map<String, Object> map : list) {
//iterate every entry in the object
for (Map.Entry<String, Object> entry : map.entrySet()) {
if (entry.getKey().equals("kids")) {
//you can store the key and the value however you want/need
System.out.println(entry.getKey() + " -> " + entry.getValue());
}
}
}

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
-------------------------------------------
#Test
public void test04() throws IOException {
final String preString = "[{\"id\": 1, \"name\" : \"abc\", \"above50\" : true} , {\"id\": 2, \"name\" : \"xyc\", \"above50\" : false, \"kids\" : \"yes\"} ]";
final ObjectMapper objectMapper = new ObjectMapper();
final JsonNode arrayNode = objectMapper.readTree(preString);
if (arrayNode.isArray()) {
for (JsonNode it : arrayNode) {
final JsonNode kids = it.get("kids");
if (kids != null) {
//TODO: Storage this value by you want
System.out.println(kids.asText());
}
}
}
}

You can use JSONObject or JSONArray
String message = ""list" : [{"id": 1, "name" : abc, "above50" : true} , {"id": 2, "name" : "xyc", "above50" : false, "kids" : "yes"} ]";
JSONObject jsonObject = new JSONObject(message);
JSONArray array = jsonObject.getJsonArray("list");
//so now inside the jsonArray there is 2 jsonObject
//then you can parse the jsonArray and check if there is
//a jsonObject that have "kids" like jsonObject.get("kids") != null
// or jsonObject.getString("kids") != null

Dynamic way to access JSON nested values in Java

I have this JSON object:
{
"maindrawer":
{
"enabled": true,
"actions":
[
{
"type": "Section",
"title": "Section 1"
},
{
"id": 1,
"type": "Primary",
"title": "Title 1",
"badge":
{
"enabled": false,
"value": 0,
"textColor": "#000000",
"badgeColor": "#ff0990"
},
"subActions":
[
{
"id": 1,
"type": "Primary",
"title": "Sub Title 1"
}
]
}
]
}
}
This is the code I'm using to access the badge -> textColor value:
public void loadJSONFromRaw(Context context, int id)
{
json = null;
try
{
//read and return json sting
InputStream is = context.getResources().openRawResource(id);
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
json = new String(buffer, "UTF-8");
//convert json to object
Type type = new TypeToken<Map<String, Object>>() {}.getType();
Map<String, Object> data = new Gson().fromJson(json, type);
//access maindrawer property
Map<String, Object> maindrawer = (Map<String, Object>)data.get("maindrawer");
//access actions list
List<Object> actions = (List<Object>)maindrawer.get("actions");
//return first item in the list
Map<String, Object> action = (Map<String, Object>) actions.get(1);
//return badge object
Map<String, String> badge = (Map<String, String>) action.get("badge");
//access badge -> textColor value
String textColor = badge.get("textColor");
}
catch (IOException e)
{
e.printStackTrace();
}
}
Is there a better/faster or more dynamic way to access JSON nested properties using java/android? I'm using Gson library for this task and don't mind to switch to any other solution to make it easier as this is too much of code to write just to access a single variable.
Ideally, I'm looking for something like:
String textColor = data.get("maindrawer").get("actions").get(1).get("badge").get("textColor");
Also I'm not very interested in using POJO for now.
Lastly, I'm still new to Java so I'm probably missing something here or maybe there are some limitations? anyways thanks for you help!!

Found what I need using JsonPath library. It looks like it does similar to what I need. Here's a sample code I found:
String textColor = JsonPath.parse(json).read("$.maindrawer.actions[1].badge.textColor");
Very clean and straightforward. Hopes this will save someone else's time as well.

Since you are accessing json file locally, it means you know its structure.
So instead of using -
Map<String, Object> data = new Gson().fromJson(json, type);
You can use something like this-
Map<String, MainDrawer> data = new Gson().fromJson(json, type);
where MainDrawer is a class with member variables - enabled, actions and array of another type.
That would make easier to fetch your values like using -
mainDrawer.isEnabled()

Here are two solutions without importing a new library.
Write a simple path parser:
String textColor = (String)parse(data, "maindrawer", "actions", 1, "badge", "textColor");
//...
static Object parse(Object root, Object... params) {
Object current = root;
for (Object p : params) {
if (p instanceof Number) {
current = ((List<?>)current).get(((Number)p).intValue());
} else {
current = ((Map<?,?>)current).get(p.toString());
}
}
return current;
}
Or parse and walk through Gson's JsonElement:
JsonElement root = new Gson().fromJson(json, JsonElement.class);
String textColor = root
.getAsJsonObject().get("maindrawer")
.getAsJsonObject().get("actions")
.getAsJsonArray().get(1)
.getAsJsonObject().get("badge")
.getAsJsonObject().get("textColor")
.getAsString();

You can also do this with BSON using a single line query. You have to cast the object to the type as you go down into Nested JSON objects.
//import java.util.ArrayList;
//import org.bson.Document;
Document root = Document.parse("{ \"maindrawer\" : { \"enabled\" : true, \"actions\" : [{ \"type\" : \"Section\", \"title\" : \"Section 1\" }, { \"id\" : 1, \"type\" : \"Primary\", \"title\" : \"Title 1\", \"badge\" : { \"enabled\" : false, \"value\" : 0, \"textColor\" : \"#000000\", \"badgeColor\" : \"#ff0990\" }, \"subActions\" : [{ \"id\" : 1, \"type\" : \"Primary\", \"title\" : \"Sub Title 1\" }] }] } }");
System.out.println(((String)((Document)((Document)((ArrayList)((Document)root.get("maindrawer")).get("actions")).get(1)).get("badge")).get("textColor")));

iterate a List<HashMap<String, String>> values using java

I have a json response like this
{
"queryPath": "/api/",
"nId": "f084f5ad24fcfaa9e9faea0",
"statusCode": 707
"statusMessage": "Success",
"results": {
"data": [
{
"id": "10248522500798",
"capabilities": [
"men",
"women"
],
"name": "errt2"
},
{
"id": "418143778",
"capabilities": [
"dog",
"cat"
],
"name": "Livin"
}
]
}
}
Here am adding results.data to a list as follows
private List<HashMap<String, String>> episodes = new ArrayList<HashMap<String, String>>();
episodes =helper.getJSONValue(response, "results.data");
public <T>T getJSONValue(Response res, String path ){
String json = res.asString();
JsonPath jpath = new JsonPath(json);
return jpath.get(path);
}
so episodes contains all data i mean all results.data
While i debuging am getting this way
[{id=10248522500798, name=errt2, capabilities=[men, women]}, {id=418143778, name=Livin, capabilities=[dog, cat]}]
Here i have capabilities [men, women] and [dog, cat].i need to check capability contains men or dog.
How can i do that?

If i were you i haven't done this..
Use gson and map your json into a java model. It's way better. Afterwards you can access all your model parts with getters and setters.
MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2
As you see it's very simple :)
But if you want to iterate a list that contains a map you can use code block below:
List<Map<String, String>> test = new ArrayList<Map<String, String>>();
for( Map<String, String> map : test ){
for( Entry<String, String> entry : map.entrySet() ){
System.out.println( entry.getKey() + " : " + entry.getValue() );
}
}
With the code above you can get all the entry's keys and values and check them.
Edit:
You have to change your List to List<Map<String,Object>> after that:
List<Map<String, Object>> test = new ArrayList<Map<String, Object>>();
for( Map<String, Object> map : test ){
for( Entry<String, Object> entry : map.entrySet() ){
if( entry.getKey().equalsIgnoreCase( "capabilities" ) ){
List<String> myCapabilities = ( List )entry.getValue();
if( myCapabilities.contains( "dog" ) && myCapabilities.contains( "cat" ) ){
// BLA BLA
}
}
}
}
It's a nasty way.. I recommend you to use gson..

Check if a particular JSON Object is available or not

I have JSON File as below which has to be dumped into an ArrayList:
{
"main1" : [
{
"child1" : valueA,
"child2" : valueB,
"child3" : valueC,
},
{
"child1" : value1,
"child3" : value3,
},
],
"main2" : "valueMain2"
}
The element child2 has to be checked if it exists or not and then the value is taken. You can see that it doesn't appear in the second array.
I am using Native JSON (org.JSON)
Java Code is below:
ArrayList<HashMap<String,String>> myList = new ArrayList<HashMap<String,String>>();
JSONObject json = <my_json_object>;
JSONObject getchild2;
JSONArray jArray = <my_json_object>.getJSONArray("main1");
for(int j = 0; j < jArray.length(), j++){
HashMap<String,String> map = new HashMap<String,String>();
map.put("First Value", jArray.getJSONObject(j).getString("child1"));
map.put("Third Value", jArray.getJSONObject(j).getString("child3"));
getchild2 = jArray.getJSONObject(j).getJSONObject("child2");
if(getchild2 == null){
map.put("Second Value", "Some Dummy Value");
} else {
map.put("Second Value", jArray.getJSONObject(j).getString("child2"));
}
myList.add(map);
}
How can I achieve this?
<my_json_object> uses native URL Parsing as I get the HTTP Response of a URL request found here: http://mobisys.in/blog/2012/01/parsing-json-from-url-in-android/
It doesn't work as error is below:
E/AndroidRuntime(664): Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0

Anyway, I got the solution with some Googling:
I re-framed it as,
if (!jArray.getJSONObject(j).has("child2")) {
map.put("Second Value", "N.A");
} else {
map.put("Second Value", jArray.getJSONObject(j).getString("child2"));
}
Creating the JSONObject getchild2 = jArray.getJSONObject(j).getJSONObject("child2"); was rather, unnecessary.
And this works, rather perfectly! Refer this for more details: Checking if exists subObject in JSON
Thanks everyone for the help!

getJSONObject("child2");
Will throw an exception if child2 does not exist. Try this instead:
getchild2 = jArray.getJSONObject(j).optJSONObject("child2");
That way you don't have to catch an exception if child2 doesn't exist and can instead check for null.

Try this:
{"main1" : [{
"id":"1"
"child1" : "valueA",
"child2" : "valueB",
"child3" : "valueC",
}, {
"id":"2"
"child1" : "value1",
"child3" : "value3",
}]
}