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Convert JSON to MAP using GSON library

I want to convert JSON response to Map what is the best approach to get the desired output using GSON library.
I try this and I'm getting only the ArrayList value.
Map<String, Object> map = gson.fromJson(response, HashMap.class);
ArrayList responseOptions = (ArrayList) map.get("data");
output:
[{language=Java, value=8}, {language=Ruby, value=7}, {language=Python, value=7}]
Sample JSON Response
{
"data":[
{
"language":"Java","value":"8"
},
{
"language":"Ruby","value":"7"
},
{
"language":"Python","value":"6"
}]
}
Desired Output in Map
{Java=8, Ruby=7, Python=6}

Test code
String str = "{\n" +
" \"data\":[\n" +
" {\n" +
" \"language\":\"Java\",\"value\":\"8\"\n" +
" },\n" +
" {\n" +
" \"language\":\"Ruby\",\"value\":\"7\"\n" +
" },\n" +
" {\n" +
" \"language\":\"Python\",\"value\":\"6\"\n" +
" }]\n" +
"}";
Map map = new Gson().fromJson(str, Map.class);
List data = (List) map.get("data");
Map<String, String> result = new HashMap<>();
for (Object o : data) {
Map m = (Map) o;
result.put(m.get("language").toString(), m.get("value").toString());
}
System.out.println(result);
Test result

I have json object with contain a list of other object and want to convert it in HashMap in java

this is the json , I wanted to convert to HashMap
`
ob = "{
"arrival": "RONGO",
"segmentPrices": [
{
"id": "",
"localId": "",
"localCode": "",
"localDesignation": "",
"amounts": [
{
"value": 950,
"currency": "Ksh"
}
]
}
]
} ";
Gson gson = new Gson();
HashMap<String,Object> result = new ObjectMapper().readValue(gson.toJson(ob), HashMap.class);
`
but i can't access to amounts object,
the value of result.get("amounts") is null
somebody can please help me for this ?

Using gson 2.0 here is what you can parse your json as HashMap and access amounts array:
public static void main(String[] args) throws IOException {
Gson gson = new Gson();
HashMap<String, Object> map = gson.fromJson(new FileReader("test.json"), HashMap.class);
ArrayList<Object> prices = (ArrayList<Object>) map.get("segmentPrices");
prices.forEach(p -> {
if (p instanceof LinkedHashMap) {
System.out.println(((LinkedHashMap)p).get("amounts"));
}
});
}
test.json file contains your json.
Output is:
[{value=950.0, currency=Ksh}]
You can access the parameters inside the object in the amount array as below:
public static void main(String[] args) throws IOException {
Gson gson = new Gson();
HashMap<String, Object> map = gson.fromJson(new FileReader("test.json"), HashMap.class);
ArrayList<Object> prices = (ArrayList<Object>) map.get("segmentPrices");
prices.forEach(p -> {
if (p instanceof LinkedHashMap) {
ArrayList<Object> amounts = (ArrayList<Object>) (((LinkedHashMap)p).get("amounts"));
amounts.forEach(amount -> {
System.out.println(((HashMap<String,Object>)amount).get("value"));
});
}
});
}
output is :
950.0

you will need the java-son library, if you need to extract the value of value this is how you can do it.
String ob = "{\n"
+ " \"arrival\": \"RONGO\",\n"
+ " \"segmentPrices\": [\n"
+ " {\n"
+ " \"id\": \"\",\n"
+ " \"localId\": \"\",\n"
+ " \"localCode\": \"\",\n"
+ " \"localDesignation\": \"\",\n"
+ " \"amounts\": [\n"
+ " {\n"
+ " \"value\": 950,\n"
+ " \"currency\": \"Ksh\"\n"
+ " }\n"
+ " ]\n"
+ " }\n"
+ " ]\n"
+ " } ";
JSONObject json = new JSONObject(ob.toString());
System.out.println(json.getJSONArray("segmentPrices").getJSONObject(0).getJSONArray("amounts").getJSONObject(0).get("value"));

check if there are two or more equal values in Json

How I should process this Json, to extract the cat1 value once in a Spinner, and in the second Spinner based on the first spinner selection I display book1 and book2.
Json:
{
"library":
[
{
"Cat": "cat1",
"Book": "book1",
"authur": "authur1"
},
{
"Cat": "cat1",
"Book": "book2",
"authur": "authur2"
},
{
"Cat": "cat2",
"Book": "book3",
"authur": "authur3"
}
]
}

You can simply use a library like Gson or Jackson for creating domain objects (you need to define them before) out of the Json. Afterwards you can easily extract whatever values you like.
This is an example:
http://www.mkyong.com/java/how-to-convert-java-object-to-from-json-jackson/

Parse your JSON data and store it into ArrayList and populate it on Spinner using ArrayAdapter.
Here is a sample code for parsing your JSON data:
public void parseJson() {
String response = "{\n" +
" \"library\":\n" +
"[\n" +
"{\n" +
" \"Cat\": \"cat1\",\n" +
" \"Book\": \"book1\",\n" +
" \"authur\": \"authur1\"\n" +
" },\n" +
" {\n" +
" \"Cat\": \"cat1\",\n" +
" \"Book\": \"book2\",\n" +
" \"authur\": \"authur2\"\n" +
" },\n" +
" {\n" +
" \"Cat\": \"cat2\",\n" +
" \"Book\": \"book3\",\n" +
" \"authur\": \"authur3\"\n" +
" }\n" +
"]\n" +
"}";
try {
JSONObject mJsonObject = new JSONObject(response);
JSONArray libraryJsonArray = mJsonObject.getJSONArray("library");
ArrayList<String> cats = new ArrayList<>();
ArrayList<String> books = new ArrayList<>();
ArrayList<String> authors = new ArrayList<>();
// Get all jsonObject from jsonArray
for (int i = 0; i < libraryJsonArray.length(); i++)
{
JSONObject jsonObject = libraryJsonArray.getJSONObject(i);
// Cat
if (jsonObject.has("Cat") && !jsonObject.isNull("Cat")) {
cats.add(jsonObject.getString("Cat"));
}
// Book
if (jsonObject.has("Book") && !jsonObject.isNull("Book")) {
books.add(jsonObject.getString("Book"));
}
// Author
if (jsonObject.has("authur") && !jsonObject.isNull("authur")) {
authors.add(jsonObject.getString("authur"));
}
Log.d("SUCCESS", "JSON Object: " + "\nCat: " + cats.get(i)
+ "\nBook: " + books.get(i) + "\nAuthor: " + authors.get(i));
// Do something with ArrayList cats, books and authors
}
} catch (JSONException e) {
Log.e("FAILED", "Json parsing error: " + e.getMessage());
}
}
OUTPUT:
D/SUCCESS: JSON Object:
Cat: cat1
Book: book1
Author: authur1
D/SUCCESS: JSON Object:
Cat: cat1
Book: book2
Author: authur2
D/SUCCESS: JSON Object:
Cat: cat2
Book: book3
Author: authur3

How to add data to a nested hashmap correctly

I am parsing json file and adding the schema information to a nested hash map.But when I tried to print the nested hashmap it is giving me the same values for all key.Need help on how to store data into a nested hashmap correctly.
My json file :
{
"status":"success",
"tables":[
{
"dbname":"idn",
"tableName":"my_monthly_hits_b",
"schema":"(cm11:chararray)",
"location":"/user/mydb/"
},
{
"dbname":"idn",
"tableName": "my_monthly_match",
"schema":"(city:chararray,match:chararray,cm11:chararray)",
"location":"/user/mydb1"
}
]
}
My code :
public Map<String,Map<String,String>> getDataTypes(String responsePath){
Map<String,Map<String,String>> maped = new HashMap<String,Map<String,String>>();
Map<String,String> colDataTypes = new HashMap<String,String>();
try{
JsonParser parser = new JsonParser();
Object obj = parser.parse(new FileReader(responsePath);
JsonObject jObj = (JsonObject) obj;
JsonArray jArray = (JsonArray) jObj.get("tables");
Iterator<JsonElement> itr = jArray.iterator();
while(itr.hasNext())
{
JsonObject innerObj = (JsonObject) itr.next();
JsonElement shm = innerObj.get("schema");
JsonElement jTableName = innerObj.get("tableName");
String tableName = jTableName.toString();
String ss = shm.toString().replaceAll("\"","").replaceAll("[()]",""):
System.out.println("The required JSON string --->" + ss);
if(ss.contains(","){
String[] str = ss.split(",");
for(String s: str){
String[] ptr = s.split(":");
colDataTypes.put(prt[0],ptr[1]);
}
}
else{
String[] str1 = ss.split(":");
colDataTypes.put(str1[0],str1[1]);
}
maped.put(tabName,colDataTypes);
for(String tab : maped.keySet()){
System.out.println("#####" + "Table Name " + tab + "value" + maped.get(tab));
}
}
}
catch(FileNotFoundException ex)
{
}
return maped;
}

You can use a library like Jackson to manipulate the JSON tree (shown here) or marshal the JSON to an object graph.
package foo;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
public class Foo {
public static void main(String[] args) throws Exception {
final ObjectMapper mapper = new ObjectMapper();
final JsonNode node = mapper.readTree("{ " +
" \"status\":\"success\"," +
" \"tables\":[ " +
" { " +
" \"dbname\":\"idn\"," +
" \"tableName\":\"my_monthly_hits_b\"," +
" \"schema\":\"(cm11:chararray)\"," +
" \"location\":\"/user/mydb/\"" +
" }," +
" { " +
" \"dbname\":\"idn\"," +
" \"tableName\":\"my_monthly_match\"," +
" \"schema\":\"(city:chararray,match:chararray,cm11:chararray)\"," +
" \"location\":\"/user/mydb1\"" +
" }" +
" ]" +
"}");
final ArrayNode tables = (ArrayNode) node.get("tables");
// Add a new schema
final ObjectNode newSchema = tables.addObject();
newSchema.put("dbname", "foo db name");
newSchema.put("tableName", "foo table name");
newSchema.put("schema", "(foo:chararray,bar:chararray)");
newSchema.put("location", "/foo/bar");
mapper.enable(SerializationFeature.INDENT_OUTPUT);
System.out.println(mapper.writeValueAsString(node));
}
}
The example above will print:
{
"status" : "success",
"tables" : [ {
"dbname" : "idn",
"tableName" : "my_monthly_hits_b",
"schema" : "(cm11:chararray)",
"location" : "/user/mydb/"
}, {
"dbname" : "idn",
"tableName" : "my_monthly_match",
"schema" : "(city:chararray,match:chararray,cm11:chararray)",
"location" : "/user/mydb1"
}, {
"dbname" : "foo db name",
"tableName" : "foo table name",
"schema" : "(foo:chararray,bar:chararray)",
"location" : "/foo/bar"
} ]
}

Parsing JSON string in Java

I am trying to parse a JSON string in java to have the individual value printed separately. But while making the program run I get the following error-
Exception in thread "main" java.lang.RuntimeException: Stub!
at org.json.JSONObject.<init>(JSONObject.java:7)
at ShowActivity.main(ShowActivity.java:29)
My Class looks like-
import org.json.JSONException;
import org.json.JSONObject;
public class ShowActivity {
private final static String jString = "{"
+ " \"geodata\": ["
+ " {"
+ " \"id\": \"1\","
+ " \"name\": \"Julie Sherman\","
+ " \"gender\" : \"female\","
+ " \"latitude\" : \"37.33774833333334\","
+ " \"longitude\" : \"-121.88670166666667\""
+ " }"
+ " },"
+ " {"
+ " \"id\": \"2\","
+ " \"name\": \"Johnny Depp\","
+ " \"gender\" : \"male\","
+ " \"latitude\" : \"37.336453\","
+ " \"longitude\" : \"-121.884985\""
+ " }"
+ " }"
+ " ]"
+ "}";
private static JSONObject jObject = null;
public static void main(String[] args) throws JSONException {
jObject = new JSONObject(jString);
JSONObject geoObject = jObject.getJSONObject("geodata");
String geoId = geoObject.getString("id");
System.out.println(geoId);
String name = geoObject.getString("name");
System.out.println(name);
String gender=geoObject.getString("gender");
System.out.println(gender);
String lat=geoObject.getString("latitude");
System.out.println(lat);
String longit =geoObject.getString("longitude");
System.out.println(longit);
}
}
Let me know what is it I am missing, or the reason why I do get that error everytime I run the application. Any comments would be appreciated.

See my comment.
You need to include the full org.json library when running as android.jar only contains stubs to compile against.
In addition, you must remove the two instances of extra } in your JSON data following longitude.
private final static String JSON_DATA =
"{"
+ " \"geodata\": ["
+ " {"
+ " \"id\": \"1\","
+ " \"name\": \"Julie Sherman\","
+ " \"gender\" : \"female\","
+ " \"latitude\" : \"37.33774833333334\","
+ " \"longitude\" : \"-121.88670166666667\""
+ " },"
+ " {"
+ " \"id\": \"2\","
+ " \"name\": \"Johnny Depp\","
+ " \"gender\" : \"male\","
+ " \"latitude\" : \"37.336453\","
+ " \"longitude\" : \"-121.884985\""
+ " }"
+ " ]"
+ "}";
Apart from that, geodata is in fact not a JSONObject but a JSONArray.
Here is the fully working and tested corrected code:
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class ShowActivity {
private final static String JSON_DATA =
"{"
+ " \"geodata\": ["
+ " {"
+ " \"id\": \"1\","
+ " \"name\": \"Julie Sherman\","
+ " \"gender\" : \"female\","
+ " \"latitude\" : \"37.33774833333334\","
+ " \"longitude\" : \"-121.88670166666667\""
+ " },"
+ " {"
+ " \"id\": \"2\","
+ " \"name\": \"Johnny Depp\","
+ " \"gender\" : \"male\","
+ " \"latitude\" : \"37.336453\","
+ " \"longitude\" : \"-121.884985\""
+ " }"
+ " ]"
+ "}";
public static void main(final String[] argv) throws JSONException {
final JSONObject obj = new JSONObject(JSON_DATA);
final JSONArray geodata = obj.getJSONArray("geodata");
final int n = geodata.length();
for (int i = 0; i < n; ++i) {
final JSONObject person = geodata.getJSONObject(i);
System.out.println(person.getInt("id"));
System.out.println(person.getString("name"));
System.out.println(person.getString("gender"));
System.out.println(person.getDouble("latitude"));
System.out.println(person.getDouble("longitude"));
}
}
}
Here's the output:
C:\dev\scrap>java -cp json.jar;. ShowActivity
1
Julie Sherman
female
37.33774833333334
-121.88670166666667
2
Johnny Depp
male
37.336453
-121.884985

To convert your JSON string to hashmap you can make use of this :
HashMap<String, Object> hashMap = new HashMap<>(Utility.jsonToMap(response)) ;
Use this class :) (handles even lists , nested lists and json)
public class Utility {
public static Map<String, Object> jsonToMap(Object json) throws JSONException {
if(json instanceof JSONObject)
return _jsonToMap_((JSONObject)json) ;
else if (json instanceof String)
{
JSONObject jsonObject = new JSONObject((String)json) ;
return _jsonToMap_(jsonObject) ;
}
return null ;
}
private static Map<String, Object> _jsonToMap_(JSONObject json) throws JSONException {
Map<String, Object> retMap = new HashMap<String, Object>();
if(json != JSONObject.NULL) {
retMap = toMap(json);
}
return retMap;
}
private static Map<String, Object> toMap(JSONObject object) throws JSONException {
Map<String, Object> map = new HashMap<String, Object>();
Iterator<String> keysItr = object.keys();
while(keysItr.hasNext()) {
String key = keysItr.next();
Object value = object.get(key);
if(value instanceof JSONArray) {
value = toList((JSONArray) value);
}
else if(value instanceof JSONObject) {
value = toMap((JSONObject) value);
}
map.put(key, value);
}
return map;
}
public static List<Object> toList(JSONArray array) throws JSONException {
List<Object> list = new ArrayList<Object>();
for(int i = 0; i < array.length(); i++) {
Object value = array.get(i);
if(value instanceof JSONArray) {
value = toList((JSONArray) value);
}
else if(value instanceof JSONObject) {
value = toMap((JSONObject) value);
}
list.add(value);
}
return list;
}
}

credit to this blog
This answer may help someone whose requirements are different.
This is your Json string
{
"pageNumber":20,
"pageTitle":"example page title",
"pageInfo": {
"pageName": "Homepage",
"logo": "https://www.example.com/logo.jpg"
},
"posts": [
{
"post_id": "0123456789",
"actor_id": "1001",
"author_name": "Jane Doe",
"post_title": "How to parse JSON in Java",
"comments": [],
"time_of_post": "1234567890"
}
]
}
and this is how to read it
import org.json.JSONArray;
import org.json.JSONObject;
public class ParseJSON {
static String json = "...";
public static void main(String[] args) {
JSONObject obj = new JSONObject(json);
String pageTitle = obj.getString("pageTitle");
String pageNumber= obj.getInt("pageNumber");
String pageName = obj.getJSONObject("pageInfo").getString("pageName");
System.out.println(pageNumber);
System.out.println(pageTitle );
System.out.println(pageName);
JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++) {
String post_id = arr.getJSONObject(i).getString("post_id");
System.out.println(post_id);
}
}
}

Looks like for both of your objects (inside the array), you have an extra closing brace after "Longitude".

Firstly there is an extra } after every array object.
Secondly "geodata" is a JSONArray. So instead of JSONObject geoObject = jObject.getJSONObject("geodata"); you have to get it as JSONArray geoObject = jObject.getJSONArray("geodata");
Once you have the JSONArray you can fetch each entry in the JSONArray using geoObject.get(<index>).
I am using org.codehaus.jettison.json.

Here is the example of one Object, For your case you have to use JSONArray.
public static final String JSON_STRING="{\"employee\":{\"name\":\"Sachin\",\"salary\":56000}}";
try{
JSONObject emp=(new JSONObject(JSON_STRING)).getJSONObject("employee");
String empname=emp.getString("name");
int empsalary=emp.getInt("salary");
String str="Employee Name:"+empname+"\n"+"Employee Salary:"+empsalary;
textView1.setText(str);
}catch (Exception e) {e.printStackTrace();}
//Do when JSON has problem.
}
I don't have time but tried to give an idea. If you still can't do it, then I will help.

you have an extra "}" in each object,
you may write the json string like this:
public class ShowActivity {
private final static String jString = "{"
+ " \"geodata\": ["
+ " {"
+ " \"id\": \"1\","
+ " \"name\": \"Julie Sherman\","
+ " \"gender\" : \"female\","
+ " \"latitude\" : \"37.33774833333334\","
+ " \"longitude\" : \"-121.88670166666667\""
+ " }"
+ " },"
+ " {"
+ " \"id\": \"2\","
+ " \"name\": \"Johnny Depp\","
+ " \"gender\" : \"male\","
+ " \"latitude\" : \"37.336453\","
+ " \"longitude\" : \"-121.884985\""
+ " }"
+ " }"
+ " ]"
+ "}";
}