GSON parsing in Java with unknown number of objects - java

I'm new to GSON and have been having trouble parsing the JSON below. The parsing works fine until it gets to the list of bills (staring at "0":). At that point I get a null reference in the resulting gson.fromJson object. If those bills were specified in a JSON array I think it would be easy, but they're not and I can't change that. What is the best way to handle this situation?
{
"status":"OK",
"masterlist":{
"session":{
"session_id":1007,
"session_name":"97th Legislature"
},
"0":{
"bill_id":446875,
"number":"HB4001"
},
"1":{
"bill_id":446858,
"number":"HB4002"
},
"2":{
"bill_id":446842,
"number":"HB4003"
},...
This is the code in my main method:
InputStream source = retrieveStream(url);
Gson gson = new Gson();
Reader reader = new InputStreamReader(source);
ResponseData response = gson.fromJson(reader, ResponseData.class);
And this is the ResponseData class:
public class ResponseData {
private String status;
private MasterList masterlist;
public static class MasterList{
private Session session;
private Bill bill; //Also tried: Map<String, String> bill;
}
public static class Session{
private String session_id;
private String session_name;
}
public static class Bill{
private String bill_id;
private String number;
}
}

You can map the object as below:
declare an object to map with json string
public class ResponseData {
private String status;
private Map<String, MasterList> masterlist;
public Map<String, MasterList> getMasterlist() {
return masterlist;
}
public void setMasterlist(Map<String, MasterList> masterlist) {
this.masterlist = masterlist;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public static class MasterList {
private String session_id;
private String session_name;
private String bill_id;
private String number;
public String getSession_id() {
return session_id;
}
public void setSession_id(String session_id) {
this.session_id = session_id;
}
public String getSession_name() {
return session_name;
}
public void setSession_name(String session_name) {
this.session_name = session_name;
}
public String getBill_id() {
return bill_id;
}
public void setBill_id(String bill_id) {
this.bill_id = bill_id;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
}
}
And use it as below:
String data = "{\"status\":\"OK\",\"masterlist\":{ \"session\":{ \"session_id\":1007, \"session_name\":\"97th Legislature\" }, \"0\":{ \"bill_id\":446875, \"number\":\"HB4001\" }, \"1\":{ \"bill_id\":446858, \"number\":\"HB4002\" }, \"2\":{ \"bill_id\":446842, \"number\":\"HB4003\" }}}";
Gson gson = new Gson();
ResponseData response = gson.fromJson(data, ResponseData.class);
for (Iterator<Entry<String, MasterList>> it = response.getMasterlist().entrySet().iterator(); it.hasNext(); ) {
Map.Entry<String, MasterList> entry = it.next();
System.out.println(entry.getKey());
System.out.println(entry.getValue().getSession_id());
}

Related

how to access to json with java

I have in a rest response this json:
{
"TRANS": {
"HPAY": [
{
"ID": "1234",
"DATE": "10/09/2011 18:09:27",
"REC": "wallet Ricaricato",
"COM": "Tasso Commissione",
"MSG": "Commento White Brand",
"STATUS": "3",
"EXTRA": {
"IS3DS": "0",
"CTRY": "FRA",
"AUTH": "455622"
},
"INT_MSG": "05-00-05 ERR_PSP_REFUSED",
"MLABEL": "IBAN",
"TYPE": "1"
}
]
}
}
I have made pojo class to map this json in java.
public class Trans {
private List<Hpay> hpay;
public Trans(){
}
//getter and setter
}
public class Hpay {
private String id;
private String date;
private String com;
private String msg;
private String status;
private List<Extra> extra;
private String int_msg;
private String mlabel;
private String type;
public Hpay(){
}
//getter and setter
}
I try to map the object with Gson library.
Gson gson=new Gson();
Trans transaction=gson.fromJson(response.toString(), Trans.class);
If i call hpay method on transaction i have null..i don't know why...
I have deleted previous answer and add new one as par your requirement
JSON String :
{
"TRANS": {
"HPAY": [{
"ID": "1234",
"DATE": "10/09/2011 18:09:27",
"REC": "wallet Ricaricato",
"COM": "Tasso Commissione",
"MSG": "Commento White Brand",
"STATUS": "3",
"EXTRA": {
"IS3DS": "0",
"CTRY": "FRA",
"AUTH": "455622"
},
"INT_MSG": "05-00-05 ERR_PSP_REFUSED",
"MLABEL": "IBAN",
"TYPE": "1"
}
]
}
}
Java Objects : (Here Extra is not list)
public class MyObject {
#SerializedName("TRANS")
#Expose
private Trans trans;
public Trans getTRANS() {return trans;}
public void setTRANS(Trans trans) {this.trans = trans;}
}
public class Trans {
#SerializedName("HPAY")
#Expose
private List<HPay> hPay;
public List<HPay> getHPAY() {return hPay;}
public void setHPAY(List<HPay> hPay) {this.hPay = hPay;}
}
public class HPay {
#SerializedName("ID")
#Expose
private String id;
#SerializedName("DATE")
#Expose
private String date;
#SerializedName("REC")
#Expose
private String rec;
#SerializedName("COM")
#Expose
private String com;
#SerializedName("MSG")
#Expose
private String msg;
#SerializedName("STATUS")
#Expose
private String status;
#SerializedName("EXTRA")
#Expose
private Extra extra;
#SerializedName("INT_MSG")
#Expose
private String intMsg;
#SerializedName("MLABEL")
#Expose
private String mLabel;
#SerializedName("TYPE")
#Expose
private String type;
public String getID() {return id;}
public void setID(String id) {this.id = id;}
public String getDATE() {return date;}
public void setDATE(String date) {this.date = date;}
public String getREC() {return rec;}
public void setREC(String rec) {this.rec = rec;}
public String getCOM() {return com;}
public void setCOM(String com) {this.com = com;}
public String getMSG() {return msg;}
public void setMSG(String msg) {this.msg = msg;}
public String getSTATUS() {return status;}
public void setSTATUS(String status) {this.status = status;}
public Extra getEXTRA() {return extra;}
public void setEXTRA(Extra extra) {this.extra = extra;}
public String getINTMSG() {return intMsg;}
public void setINTMSG(String intMsg) {this.intMsg = intMsg;}
public String getMLABEL() {return mLabel;}
public void setMLABEL(String mLabel) {this.mLabel = mLabel;}
public String getTYPE() {return type;}
public void setTYPE(String type) {this.type = type;}
}
public class Extra {
#SerializedName("IS3DS")
#Expose
private String is3ds;
#SerializedName("CTRY")
#Expose
private String ctry;
#SerializedName("AUTH")
#Expose
private String auth;
public String getIS3DS() { return is3ds; }
public void setIS3DS(String is3ds) { this.is3ds = is3ds; }
public String getCTRY() { return ctry; }
public void setCTRY(String ctry) { this.ctry = ctry; }
public String getAUTH() { return auth; }
public void setAUTH(String auth) { this.auth = auth; }
}
Conversion Logic :
import com.google.gson.Gson;
public class NewClass {
public static void main(String[] args) {
Gson g = new Gson();
g.fromJson(json, MyObject.class);
}
static String json = "{ \"TRANS\": { \"HPAY\": [{ \"ID\": \"1234\", \"DATE\": \"10/09/2011 18:09:27\", \"REC\": \"wallet Ricaricato\", \"COM\": \"Tasso Commissione\", \"MSG\": \"Commento White Brand\", \"STATUS\": \"3\", \"EXTRA\": { \"IS3DS\": \"0\", \"CTRY\": \"FRA\", \"AUTH\": \"455622\" }, \"INT_MSG\": \"05-00-05 ERR_PSP_REFUSED\", \"MLABEL\": \"IBAN\", \"TYPE\": \"1\" } ] } }";
}
Here I use Google Gosn lib for conversion.
And need to import bellow classes for annotation
com.google.gson.annotations.Expose;
com.google.gson.annotations.SerializedName;
First parse the json data using json.simple and then set the values using setters
Object obj = parser.parse(new FileReader( "file.json" ));
JSONObject jsonObject = (JSONObject) obj;
JSONArray hpayObj= (JSONArray) jsonObject.get("HPAY");
//get the first element of array
JSONObject details= hpayObj.getJSONArray(0);
String id = (String)details.get("ID");
//set the value of the id field in the setter of class Trans
new Trans().setId(id);
new Trans().setDate((String)details.get("DATE"));
new Trans().setRec((String)details.get("REC"));
and so on..
//get the second array element
JSONObject intMsgObj= hpayObj.getJSONArray(1);
new Trans().setIntmsg((String)details.get("INT_MSG"));
//get the third array element
JSONObject mlabelObj= hpayObj.getJSONArray(2);
new Trans().setMlabel((String)details.get("MLABEL"));
JSONObject typeObj= hpayObj.getJSONArray(3);
new Trans().setType((String)details.get("TYPE"));
Now you can get the values using your getter methods.

unable to convert json string to POJO due to error Expected a string but was BEGIN_ARRAY

For some reason i am not able to covert it to a POJO. The call i am making and have tried is like this:
NewsEntities newsEntities = new Gson().fromJson(jsonString, NewsEntities.class);
The mystery is that the json is not in an array. its a jsonObject i think.
the jsonString is here
The error i get in android is:
Caused by: java.lang.IllegalStateException: Expected a string but was BEGIN_ARRAY at line 1 column 1006 path $.results[0].org_facet
02-24 23:42:49.955 15463-15531/news.myapp.com.technewssample W/System.err: at com.google.gson.stream.JsonReader.nextString(JsonReader.java:831)
02-24 23:42:49.955 15463-15531/news.myapp.com.technewssample W/System.err: at com.google.gson.internal.bind.TypeAdapters$16.read(TypeAdapters.java:422)
02-24 23:42:49.955 15463-15531/news.myapp.com.technewssample W/System.err: at com.google.gson.internal.bind.TypeAdapters$16.read(TypeAdapters.java:410)
02-24 23:42:49.955 15463-15531/news.myapp.com.technewssample W/System.err: at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:116)
02-24 23:42:49.956 15463-15531/news.myapp.com.technewssample W/System.err: at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(Reflect
the newsEntities class itself looks like this and i simply made it from http://www.jsonschema2pojo.org/:
public class NewsEntities implements Parcelable
{
#SerializedName("status")
#Expose
private String status;
#SerializedName("copyright")
#Expose
private String copyright;
#SerializedName("section")
#Expose
private String section;
#SerializedName("last_updated")
#Expose
private String lastUpdated;
#SerializedName("num_results")
#Expose
private Integer numResults;
#SerializedName("results")
#Expose
private List<Result> results = null;
public final static Parcelable.Creator<NewsEntities> CREATOR = new Creator<NewsEntities>() {
#SuppressWarnings({
"unchecked"
})
public NewsEntities createFromParcel(Parcel in) {
NewsEntities instance = new NewsEntities();
instance.status = ((String) in.readValue((String.class.getClassLoader())));
instance.copyright = ((String) in.readValue((String.class.getClassLoader())));
instance.section = ((String) in.readValue((String.class.getClassLoader())));
instance.lastUpdated = ((String) in.readValue((String.class.getClassLoader())));
instance.numResults = ((Integer) in.readValue((Integer.class.getClassLoader())));
in.readList(instance.results, (Result.class.getClassLoader()));
return instance;
}
public NewsEntities[] newArray(int size) {
return (new NewsEntities[size]);
}
}
;
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getCopyright() {
return copyright;
}
public void setCopyright(String copyright) {
this.copyright = copyright;
}
public String getSection() {
return section;
}
public void setSection(String section) {
this.section = section;
}
public String getLastUpdated() {
return lastUpdated;
}
public void setLastUpdated(String lastUpdated) {
this.lastUpdated = lastUpdated;
}
public Integer getNumResults() {
return numResults;
}
public void setNumResults(Integer numResults) {
this.numResults = numResults;
}
public List<Result> getResults() {
return results;
}
public void setResults(List<Result> results) {
this.results = results;
}
public void writeToParcel(Parcel dest, int flags) {
dest.writeValue(status);
dest.writeValue(copyright);
dest.writeValue(section);
dest.writeValue(lastUpdated);
dest.writeValue(numResults);
dest.writeList(results);
}
public int describeContents() {
return 0;
}
}
UPDATE: HERE IS THE RESULT CLASS:
public class Result implements Parcelable
{
#SerializedName("section")
#Expose
private String section;
#SerializedName("subsection")
#Expose
private String subsection;
#SerializedName("title")
#Expose
private String title;
#SerializedName("abstract")
#Expose
private String _abstract;
#SerializedName("url")
#Expose
private String url;
#SerializedName("byline")
#Expose
private String byline;
#SerializedName("item_type")
#Expose
private String itemType;
#SerializedName("updated_date")
#Expose
private String updatedDate;
#SerializedName("created_date")
#Expose
private String createdDate;
#SerializedName("published_date")
#Expose
private String publishedDate;
#SerializedName("material_type_facet")
#Expose
private String materialTypeFacet;
#SerializedName("kicker")
#Expose
private String kicker;
#SerializedName("des_facet")
#Expose
private List<String> desFacet = null;
#SerializedName("org_facet")
#Expose
private String orgFacet;
#SerializedName("per_facet")
#Expose
private String perFacet;
#SerializedName("geo_facet")
#Expose
private List<String> geoFacet = null;
#SerializedName("multimedia")
#Expose
private List<Multimedium> multimedia = null;
public final static Parcelable.Creator<Result> CREATOR = new Creator<Result>() {
#SuppressWarnings({
"unchecked"
})
public Result createFromParcel(Parcel in) {
Result instance = new Result();
instance.section = ((String) in.readValue((String.class.getClassLoader())));
instance.subsection = ((String) in.readValue((String.class.getClassLoader())));
instance.title = ((String) in.readValue((String.class.getClassLoader())));
instance._abstract = ((String) in.readValue((String.class.getClassLoader())));
instance.url = ((String) in.readValue((String.class.getClassLoader())));
instance.byline = ((String) in.readValue((String.class.getClassLoader())));
instance.itemType = ((String) in.readValue((String.class.getClassLoader())));
instance.updatedDate = ((String) in.readValue((String.class.getClassLoader())));
instance.createdDate = ((String) in.readValue((String.class.getClassLoader())));
instance.publishedDate = ((String) in.readValue((String.class.getClassLoader())));
instance.materialTypeFacet = ((String) in.readValue((String.class.getClassLoader())));
instance.kicker = ((String) in.readValue((String.class.getClassLoader())));
in.readList(instance.desFacet, (java.lang.String.class.getClassLoader()));
instance.orgFacet = ((String) in.readValue((String.class.getClassLoader())));
instance.perFacet = ((String) in.readValue((String.class.getClassLoader())));
in.readList(instance.geoFacet, (java.lang.String.class.getClassLoader()));
in.readList(instance.multimedia, (Multimedium.class.getClassLoader()));
return instance;
}
public Result[] newArray(int size) {
return (new Result[size]);
}
}
;
public String getSection() {
return section;
}
public void setSection(String section) {
this.section = section;
}
public String getSubsection() {
return subsection;
}
public void setSubsection(String subsection) {
this.subsection = subsection;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAbstract() {
return _abstract;
}
public void setAbstract(String _abstract) {
this._abstract = _abstract;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getByline() {
return byline;
}
public void setByline(String byline) {
this.byline = byline;
}
public String getItemType() {
return itemType;
}
public void setItemType(String itemType) {
this.itemType = itemType;
}
public String getUpdatedDate() {
return updatedDate;
}
public void setUpdatedDate(String updatedDate) {
this.updatedDate = updatedDate;
}
public String getCreatedDate() {
return createdDate;
}
public void setCreatedDate(String createdDate) {
this.createdDate = createdDate;
}
public String getPublishedDate() {
return publishedDate;
}
public void setPublishedDate(String publishedDate) {
this.publishedDate = publishedDate;
}
public String getMaterialTypeFacet() {
return materialTypeFacet;
}
public void setMaterialTypeFacet(String materialTypeFacet) {
this.materialTypeFacet = materialTypeFacet;
}
public String getKicker() {
return kicker;
}
public void setKicker(String kicker) {
this.kicker = kicker;
}
public List<String> getDesFacet() {
return desFacet;
}
public void setDesFacet(List<String> desFacet) {
this.desFacet = desFacet;
}
public String getOrgFacet() {
return orgFacet;
}
public void setOrgFacet(String orgFacet) {
this.orgFacet = orgFacet;
}
public String getPerFacet() {
return perFacet;
}
public void setPerFacet(String perFacet) {
this.perFacet = perFacet;
}
public List<String> getGeoFacet() {
return geoFacet;
}
public void setGeoFacet(List<String> geoFacet) {
this.geoFacet = geoFacet;
}
public List<Multimedium> getMultimedia() {
return multimedia;
}
public void setMultimedia(List<Multimedium> multimedia) {
this.multimedia = multimedia;
}
public void writeToParcel(Parcel dest, int flags) {
dest.writeValue(section);
dest.writeValue(subsection);
dest.writeValue(title);
dest.writeValue(_abstract);
dest.writeValue(url);
dest.writeValue(byline);
dest.writeValue(itemType);
dest.writeValue(updatedDate);
dest.writeValue(createdDate);
dest.writeValue(publishedDate);
dest.writeValue(materialTypeFacet);
dest.writeValue(kicker);
dest.writeList(desFacet);
dest.writeValue(orgFacet);
dest.writeValue(perFacet);
dest.writeList(geoFacet);
dest.writeList(multimedia);
}
public int describeContents() {
return 0;
}
}
Automatic POJO generators may generate wrong mappings in some cases, especially if mapped fields are polymorphic or use non-standard approaches for whatever reasons. According to the error you're getting, your mapping expects a String but the JSON has an array at that place. In your case, $.results[0].org_facet points to:
...,"org_facet":["Amazon.com Inc","Cravath Swaine \u0026 Moore"],...
// ^____here
If you change the mapping String orgFacet to List<String> orgFacet, you'll get similar errors for another fields like perFacet or multimedia (there are some more around). Since those fields are meant to be lists and "" is just a marker for an empty array [] or null, Gson cannot handle it itself because of such a message format. However, you can make it work with such fields writing a custom type adapter that would be applicable for all lists deserialized using a single Gson instance.
final class ArrayOrEmptyStringTypeAdapter<E>
extends TypeAdapter<List<E>> {
private final Gson gson;
private final Type elementType;
private ArrayOrEmptyStringTypeAdapter(final Gson gson, final Type elementType) {
this.gson = gson;
this.elementType = elementType;
}
static <E> TypeAdapter<List<E>> getArrayOrEmptyStringTypeAdapter(final Gson gson, final Type elementType) {
return new ArrayOrEmptyStringTypeAdapter<>(gson, elementType);
}
#Override
public void write(final JsonWriter out, final List<E> list) {
throw new UnsupportedOperationException();
}
#Override
public List<E> read(final JsonReader in)
throws IOException {
final JsonToken token = in.peek(); // Peek the next token
switch ( token ) {
case BEGIN_ARRAY: // If it's an array begin `[`, then parse it as an array
return parseAsArray(in);
case STRING: // Or if it's a string, parse it in another way
return parseAsString(in);
default:
throw new MalformedJsonException("Unexpected token: " + token);
}
}
private List<E> parseAsArray(final JsonReader in)
throws IOException {
final List<E> list = new ArrayList<>();
in.beginArray(); // Consume `[` from the token stream
while ( in.peek() != END_ARRAY ) {
final E element = gson.fromJson(in, elementType); // Delegate downstream parsing to the Gson instance
list.add(element);
}
in.endArray(); // Consume `]` from the token stream
return list;
}
private List<E> parseAsString(final JsonReader in)
throws IOException {
in.skipValue(); // in.nextString() consumes more memory accumulating the result
return new ArrayList<>(); // Or null -- up to you. Or even Collections.emptyList(), but Gson uses mutable lists so we do
}
}
The next thing is binding the type adapter and a Gson instance via a type adapter factory:
final class ArrayOrEmptyStringTypeAdapterFactory
implements TypeAdapterFactory {
private static final TypeAdapterFactory arrayOrEmptyStringTypeAdapterFactory = new ArrayOrEmptyStringTypeAdapterFactory();
private ArrayOrEmptyStringTypeAdapterFactory() {
}
static TypeAdapterFactory getArrayOrEmptyStringTypeAdapterFactory() {
return arrayOrEmptyStringTypeAdapterFactory;
}
#Override
public <T> TypeAdapter<T> create(final Gson gson, final TypeToken<T> typeToken) {
if ( List.class.isAssignableFrom(typeToken.getRawType()) ) { // Is it an instance of java.util.List? Not that getRawType() and getType() have different purposes
final TypeAdapter<List<Object>> typeAdapter = getArrayOrEmptyStringTypeAdapter(gson, getListElementType(typeToken.getType()));
#SuppressWarnings("unchecked")
final TypeAdapter<T> castTypeAdapter = (TypeAdapter<T>) typeAdapter;
return castTypeAdapter;
}
return null;
}
private static Type getListElementType(final Type type) {
return type instanceof ParameterizedType // Is it a generic type with type parameters?
? ((ParameterizedType) type).getActualTypeArguments()[0] // If yes, then we know that java.util.List has one type paremeter only
: Object.class; // Otherwise it's a raw list, and no element type info is provided
}
}
How it's used:
private static final Gson gson = new GsonBuilder()
.registerTypeAdapterFactory(getArrayOrEmptyStringTypeAdapterFactory())
.create();
final NewsEntities newEntities = gson.fromJson(jsonString, NewsEntities.class);
System.out.println(newEntities.results.get(0).orgFacet);
System.out.println(newEntities.results.get(0).perFacet)
The output:
[Amazon.com Inc, Cravath Swaine & Moore]
[Bezos, Jeffrey P]
You haven't attached your result class but it looks to me like your result class has a string field instead of an array in org_facet. But it would be easier to answer if you add your Result class.

Parsing JSON in Android, not getting value

I am able to parse everything i need, except for the target_id's in the field_exercis_arc. I get the nid, title and body. Not sure how to get the id's in the field_exercis_arc.
The JSON
[{
"nid": "26",
"title": "Question test",
"body": "xcvxcv",
"field_exercis_arc": ["25","27"]
}]
The Code
String finalJson = buffer.toString();
JSONArray parentArray = new JSONArray(finalJson);
List<ExerciseModel> exerciseModelList = new ArrayList<>();
for(int i=0; i<parentArray.length(); i++){
JSONObject finalObject = parentArray.getJSONObject(i);
title_exi = finalObject.getString("title");
text_exi = finalObject.getString("body");
//This part is working.
ExerciseModel exerciseModel = new ExerciseModel();
exerciseModel.setTitle(finalObject.getString("title"));
exerciseModel.setNid(finalObject.getInt("nid"));
exerciseModel.setBody(finalObject.getString("body"));
//Problem with this part, not getting the target_id's.
List<ExerciseModel.Exer> exerList = new ArrayList<>();
for(int j=0; j<finalObject.getJSONArray("field_exercis_arc").length(); j++){
ExerciseModel.Exer exercis = new ExerciseModel.Exer();
exercis.setTarget_id(finalObject.getJSONArray("field_exercis_arc").getJSONObject(j).getString("target_id"));
exerList.add(exercis);
}
exerciseModel.setExerList(exerList);
exerciseModelList.add(exerciseModel);
mDB.saveRecordEX(exerciseModel);
}
The model for the field_exercis_arc and target_id's fields
private List<Exer> exerList;
public List<Exer> getExerList() {
return exerList;
}
public void setExerList(List<Exer> exerList) {
this.exerList = exerList;
}
public static class Exer{
private String target_id;
public String getTarget_id() {
return target_id;
}
public void setTarget_id(String target_id) {
this.target_id = target_id;
}
}
Thanks in advance
I recommend you to use GSON library to get result from JSON. For that you will need Java class in order to parse result to object. For this you can use JSON to Java Class conversion here.
For you example classes would be:
public class Und
{
private String value;
public String getValue() { return this.value; }
public void setValue(String value) { this.value = value; }
}
public class Body
{
private ArrayList<Und> und;
public ArrayList<Und> getUnd() { return this.und; }
public void setUnd(ArrayList<Und> und) { this.und = und; }
}
public class Und2
{
private String target_id;
public String getTargetId() { return this.target_id; }
public void setTargetId(String target_id) { this.target_id = target_id; }
}
public class FieldExercisArc
{
private ArrayList<Und2> und;
public ArrayList<Und2> getUnd() { return this.und; }
public void setUnd(ArrayList<Und2> und) { this.und = und; }
}
public class RootObject
{
private String vid;
public String getVid() { return this.vid; }
public void setVid(String vid) { this.vid = vid; }
private String uid;
public String getUid() { return this.uid; }
public void setUid(String uid) { this.uid = uid; }
private String title;
public String getTitle() { return this.title; }
public void setTitle(String title) { this.title = title; }
private Body body;
public Body getBody() { return this.body; }
public void setBody(Body body) { this.body = body; }
private FieldExercisArc field_exercis_arc;
public FieldExercisArc getFieldExercisArc() { return this.field_exercis_arc; }
public void setFieldExercisArc(FieldExercisArc field_exercis_arc) { this.field_exercis_arc = field_exercis_arc; }
private String cid;
public String getCid() { return this.cid; }
public void setCid(String cid) { this.cid = cid; }
private String last_comment_timestamp;
public String getLastCommentTimestamp() { return this.last_comment_timestamp; }
public void setLastCommentTimestamp(String last_comment_timestamp) { this.last_comment_timestamp = last_comment_timestamp; }
}
You can convert result to RootObject. Fox example:
String json = "{\"vid\": \"26\",\"uid\": \"1\",\"title\": \"Question test\",\"body\": {\"und\": [{\"value\": \"xcvxcv\"}]},\"field_exercis_arc\": {\"und\": [{\"target_id\": \"25\"},{\"target_id\":\"27\"}]},\"cid\": \"0\",\"last_comment_timestamp\": \"1472217577\"}";
RootObject object = new Gson().fromJson(json, RootObject.class);
System.out.println("Title is: "+object.getTitle() );
Result is:
Title is: Question test
After this you can use your object to get any value from your JSON.
Also you should know that your JSON is not valid. You have commas on two places that should not exists. In string i gave you above those are fixed. You should check you JSON with: JSON Formatter
Use below code :
exercis.setTarget_id(finalObject.getJSONArray("field_exercis_arc").getString(j));
JsonArray fieldArray=yourJsonObject.getJsonArray("field_exercis_arc");
for(int i=0;i<fieldArray.length;i++){
fieldArray.getString(i);
}
TO the parse the JSON you have to do it like this.
String finalJson = buffer.toString();
JSONArray parentArray = new JSONArray(finalJson);
for(int i=0; i<parentArray.length(); i++){
JSONObject finalObject = parentArray.getJSONObject(i);
String title = finalObject.getString("title");
String body = finalObject.getString("body");
JSONArray arr = finalObject.getJSONArray("field_exercis_arc");
for(int x=0; x < arr.length(); x++){
String val = arr.getString(x);
}
}

Storing JSON object using Volley

This is the structure of the JSON I need to Load,
{
"readme_0" : "THIS JSON IS THE RESULT OF YOUR SEARCH QUERY - THERE IS NO WEB PAGE WHICH SHOWS THE RESULT!",
"readme_1" : "loklak.org is the framework for a message search system, not the portal, read: http://loklak.org/about.html#notasearchportal",
"readme_2" : "This is supposed to be the back-end of a search portal. For the api, see http://loklak.org/api.html",
"readme_3" : "Parameters q=(query), source=(cache|backend|twitter|all), callback=p for jsonp, maximumRecords=(message count), minified=(true|false)",
"search_metadata" : {
"itemsPerPage" : "100",
"count" : "100",
"count_twitter_all" : 0,
"count_twitter_new" : 100,
"count_backend" : 0,
"count_cache" : 78780,
"hits" : 78780,
"period" : 3066,
"query" : "apple",
"client" : "180.215.121.78",
"time" : 5219,
"servicereduction" : "false",
"scraperInfo" : "http://45.55.245.191:9000,local"
},
"statuses" : [ {
"created_at" : "2016-01-09T12:11:38.000Z",
"screen_name" : "arifazmi92",
"text" : "Perhaps I shouldn't have eaten that pisang goreng cheese perisa green apple. <img class=\"Emoji Emoji--forText\" src=\"https://abs.twimg.com/emoji/v2/72x72/1f605.png\" draggable=\"false\" alt=\"😅\" title=\"Smiling face with open mouth and cold sweat\" aria-label=\"Emoji: Smiling face with open mouth and cold sweat\"><img class=\"Emoji Emoji--forText\" src=\"https://abs.twimg.com/emoji/v2/72x72/1f605.png\" draggable=\"false\" alt=\"😅\" title=\"Smiling face with open mouth and cold sweat\" aria-label=\"Emoji: Smiling face with open mouth and cold sweat\"><img class=\"Emoji Emoji--forText\" src=\"https://abs.twimg.com/emoji/v2/72x72/1f605.png\" draggable=\"false\" alt=\"😅\" title=\"Smiling face with open mouth and cold sweat\" aria-label=\"Emoji: Smiling face with open mouth and cold sweat\">",
"link" : "https://twitter.com/arifazmi92/status/685796067082813440",
"id_str" : "685796067082813440",
"source_type" : "TWITTER",
"provider_type" : "SCRAPED",
"retweet_count" : 0,
"favourites_count" : 0,
"images" : [ ],
"images_count" : 0,
"audio" : [ ],
"audio_count" : 0,
"videos" : [ ],
"videos_count" : 0,
"place_name" : "Bandar Shah Alam, Selangor",
"place_id" : "9be3b0eca6c21f6c",
"place_context" : "FROM",
"place_country" : "Malaysia",
"place_country_code" : "MY",
"place_country_center" : [ -59.30559537806809, 3.4418498787292435 ],
"location_point" : [ 101.53280621465888, 3.0850698533863863 ],
"location_radius" : 0,
"location_mark" : [ 101.52542227271437, 3.0911033774188725 ],
"location_source" : "PLACE",
"hosts" : [ "abs.twimg.com" ],
"hosts_count" : 1,
"links" : [ "https://abs.twimg.com/emoji/v2/72x72/1f605.png\"", "https://abs.twimg.com/emoji/v2/72x72/1f605.png\"", "https://abs.twimg.com/emoji/v2/72x72/1f605.png\"" ],
"links_count" : 3,
"mentions" : [ ],
"mentions_count" : 0,
"hashtags" : [ ],
"hashtags_count" : 0,
"without_l_len" : 626,
"without_lu_len" : 626,
"without_luh_len" : 626,
"user" : {
"screen_name" : "arifazmi92",
"user_id" : "44503967",
"name" : "Arif Azmi",
"profile_image_url_https" : "https://pbs.twimg.com/profile_images/685788990004301824/NbFnnLuO_bigger.jpg",
"appearance_first" : "2016-01-09T12:11:57.933Z",
"appearance_latest" : "2016-01-09T12:11:57.933Z"
}
}
} ],
"aggregations" : { }
}
And these are my POJO classes that I've generated:
MainPojo.class
public class MainPojo
{
#SerializedName("readme_0")
#Expose
private String readme0;
#SerializedName("readme_1")
#Expose
private String readme1;
#SerializedName("readme_2")
#Expose
private String readme2;
#SerializedName("readme_3")
#Expose
private String readme3;
#SerializedName("search_metadata")
#Expose
private SearchMetadata searchMetadata;
#SerializedName("statuses")
#Expose
private List<Status> statuses = new ArrayList<Status>();
#SerializedName("aggregations")
#Expose
private Aggregations aggregations;
public String getReadme0() {
return readme0;
}
public void setReadme0(String readme0) {
this.readme0 = readme0;
}
public String getReadme1() {
return readme1;
}
public void setReadme1(String readme1) {
this.readme1 = readme1;
}
public String getReadme2() {
return readme2;
}
public void setReadme2(String readme2) {
this.readme2 = readme2;
}
public String getReadme3() {
return readme3;
}
public void setReadme3(String readme3) {
this.readme3 = readme3;
}
public SearchMetadata getSearchMetadata() {
return searchMetadata;
}
public void setSearchMetadata(SearchMetadata searchMetadata) {
this.searchMetadata = searchMetadata;
}
public List<Status> getStatuses() {
return statuses;
}
public void setStatuses(List<Status> statuses) {
this.statuses = statuses;
}
public Aggregations getAggregations() {
return aggregations;
}
public void setAggregations(Aggregations aggregations) {
this.aggregations = aggregations;
}
}
Status.class
public class Status
{
#SerializedName("created_at")
#Expose
private String createdAt;
#SerializedName("screen_name")
#Expose
private String screenName;
#SerializedName("text")
#Expose
private String text;
#SerializedName("link")
#Expose
private String link;
#SerializedName("id_str")
#Expose
private String idStr;
#SerializedName("source_type")
#Expose
private String sourceType;
#SerializedName("provider_type")
#Expose
private String providerType;
#SerializedName("retweet_count")
#Expose
private Integer retweetCount;
#SerializedName("favourites_count")
#Expose
private Integer favouritesCount;
#SerializedName("images")
#Expose
private List<Object> images = new ArrayList<Object>();
#SerializedName("images_count")
#Expose
private Integer imagesCount;
#SerializedName("audio")
#Expose
private List<Object> audio = new ArrayList<Object>();
#SerializedName("audio_count")
#Expose
private Integer audioCount;
#SerializedName("videos")
#Expose
private List<Object> videos = new ArrayList<Object>();
#SerializedName("videos_count")
#Expose
private Integer videosCount;
#SerializedName("place_name")
#Expose
private String placeName;
#SerializedName("place_id")
#Expose
private String placeId;
#SerializedName("place_context")
#Expose
private String placeContext;
#SerializedName("location_point")
#Expose
private List<Double> locationPoint = new ArrayList<Double>();
#SerializedName("location_radius")
#Expose
private Integer locationRadius;
#SerializedName("location_mark")
#Expose
private List<Double> locationMark = new ArrayList<Double>();
#SerializedName("location_source")
#Expose
private String locationSource;
#SerializedName("hosts")
#Expose
private List<String> hosts = new ArrayList<String>();
#SerializedName("hosts_count")
#Expose
private Integer hostsCount;
#SerializedName("links")
#Expose
private List<String> links = new ArrayList<String>();
#SerializedName("links_count")
#Expose
private Integer linksCount;
#SerializedName("mentions")
#Expose
private List<Object> mentions = new ArrayList<Object>();
#SerializedName("mentions_count")
#Expose
private Integer mentionsCount;
#SerializedName("hashtags")
#Expose
private List<Object> hashtags = new ArrayList<Object>();
#SerializedName("hashtags_count")
#Expose
private Integer hashtagsCount;
#SerializedName("without_l_len")
#Expose
private Integer withoutLLen;
#SerializedName("without_lu_len")
#Expose
private Integer withoutLuLen;
#SerializedName("without_luh_len")
#Expose
private Integer withoutLuhLen;
#SerializedName("user")
#Expose
private User user;
#SerializedName("provider_hash")
#Expose
private String providerHash;
#SerializedName("classifier_language")
#Expose
private String classifierLanguage;
#SerializedName("classifier_language_probability")
#Expose
private Double classifierLanguageProbability;
public String getCreatedAt() {
return createdAt;
}
public void setCreatedAt(String createdAt) {
this.createdAt = createdAt;
}
public String getScreenName() {
return screenName;
}
public void setScreenName(String screenName) {
this.screenName = screenName;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public String getLink() {
return link;
}
public void setLink(String link) {
this.link = link;
}
public String getIdStr() {
return idStr;
}
public void setIdStr(String idStr) {
this.idStr = idStr;
}
public String getSourceType() {
return sourceType;
}
public void setSourceType(String sourceType) {
this.sourceType = sourceType;
}
public String getProviderType() {
return providerType;
}
public void setProviderType(String providerType) {
this.providerType = providerType;
}
public Integer getRetweetCount() {
return retweetCount;
}
public void setRetweetCount(Integer retweetCount) {
this.retweetCount = retweetCount;
}
public Integer getFavouritesCount() {
return favouritesCount;
}
public void setFavouritesCount(Integer favouritesCount) {
this.favouritesCount = favouritesCount;
}
public List<Object> getImages() {
return images;
}
public void setImages(List<Object> images) {
this.images = images;
}
public Integer getImagesCount() {
return imagesCount;
}
public void setImagesCount(Integer imagesCount) {
this.imagesCount = imagesCount;
}
public List<Object> getAudio() {
return audio;
}
public void setAudio(List<Object> audio) {
this.audio = audio;
}
public Integer getAudioCount() {
return audioCount;
}
public void setAudioCount(Integer audioCount) {
this.audioCount = audioCount;
}
public List<Object> getVideos() {
return videos;
}
public void setVideos(List<Object> videos) {
this.videos = videos;
}
public Integer getVideosCount() {
return videosCount;
}
public void setVideosCount(Integer videosCount) {
this.videosCount = videosCount;
}
public String getPlaceName() {
return placeName;
}
public void setPlaceName(String placeName) {
this.placeName = placeName;
}
public String getPlaceId() {
return placeId;
}
public void setPlaceId(String placeId) {
this.placeId = placeId;
}
public String getPlaceContext() {
return placeContext;
}
public void setPlaceContext(String placeContext) {
this.placeContext = placeContext;
}
public List<Double> getLocationPoint() {
return locationPoint;
}
public void setLocationPoint(List<Double> locationPoint) {
this.locationPoint = locationPoint;
}
public Integer getLocationRadius() {
return locationRadius;
}
public void setLocationRadius(Integer locationRadius) {
this.locationRadius = locationRadius;
}
public List<Double> getLocationMark() {
return locationMark;
}
public void setLocationMark(List<Double> locationMark) {
this.locationMark = locationMark;
}
public String getLocationSource() {
return locationSource;
}
public void setLocationSource(String locationSource) {
this.locationSource = locationSource;
}
public List<String> getHosts() {
return hosts;
}
public void setHosts(List<String> hosts) {
this.hosts = hosts;
}
public Integer getHostsCount() {
return hostsCount;
}
public void setHostsCount(Integer hostsCount) {
this.hostsCount = hostsCount;
}
public List<String> getLinks() {
return links;
}
public void setLinks(List<String> links) {
this.links = links;
}
public Integer getLinksCount() {
return linksCount;
}
public void setLinksCount(Integer linksCount) {
this.linksCount = linksCount;
}
public List<Object> getMentions() {
return mentions;
}
public void setMentions(List<Object> mentions) {
this.mentions = mentions;
}
public Integer getMentionsCount() {
return mentionsCount;
}
public void setMentionsCount(Integer mentionsCount) {
this.mentionsCount = mentionsCount;
}
public List<Object> getHashtags() {
return hashtags;
}
public void setHashtags(List<Object> hashtags) {
this.hashtags = hashtags;
}
public Integer getHashtagsCount() {
return hashtagsCount;
}
public void setHashtagsCount(Integer hashtagsCount) {
this.hashtagsCount = hashtagsCount;
}
public Integer getWithoutLLen() {
return withoutLLen;
}
public void setWithoutLLen(Integer withoutLLen) {
this.withoutLLen = withoutLLen;
}
public Integer getWithoutLuLen() {
return withoutLuLen;
}
public void setWithoutLuLen(Integer withoutLuLen) {
this.withoutLuLen = withoutLuLen;
}
public Integer getWithoutLuhLen() {
return withoutLuhLen;
}
public void setWithoutLuhLen(Integer withoutLuhLen) {
this.withoutLuhLen = withoutLuhLen;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String getProviderHash() {
return providerHash;
}
public void setProviderHash(String providerHash) {
this.providerHash = providerHash;
}
public String getClassifierLanguage() {
return classifierLanguage;
}
public void setClassifierLanguage(String classifierLanguage) {
this.classifierLanguage = classifierLanguage;
}
public Double getClassifierLanguageProbability() {
return classifierLanguageProbability;
}
public void setClassifierLanguageProbability(Double classifierLanguageProbability) {
this.classifierLanguageProbability = classifierLanguageProbability;
}
}
User.java
public class User {
#SerializedName("screen_name")
#Expose
private String screenName;
#SerializedName("user_id")
#Expose
private String userId;
#SerializedName("name")
#Expose
private String name;
#SerializedName("profile_image_url_https")
#Expose
private String profileImageUrlHttps;
#SerializedName("appearance_first")
#Expose
private String appearanceFirst;
#SerializedName("appearance_latest")
#Expose
private String appearanceLatest;
public String getScreenName() {
return screenName;
}
public void setScreenName(String screenName) {
this.screenName = screenName;
}
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getProfileImageUrlHttps() {
return profileImageUrlHttps;
}
public void setProfileImageUrlHttps(String profileImageUrlHttps) {
this.profileImageUrlHttps = profileImageUrlHttps;
}
public String getAppearanceFirst() {
return appearanceFirst;
}
public void setAppearanceFirst(String appearanceFirst) {
this.appearanceFirst = appearanceFirst;
}
public String getAppearanceLatest() {
return appearanceLatest;
}
public void setAppearanceLatest(String appearanceLatest) {
this.appearanceLatest = appearanceLatest;
}
}
Aggregations.class
public class Aggregations {
}
And finally, this is the code I use to read the JSON and store as JSON objects,
SharedPreferences Tempx = getSharedPreferences("ActivitySession", Context.MODE_PRIVATE);
SharedPreferences.Editor edx = Tempx.edit();
edx.putString("GSON_FEED", response.toString());
edx.apply();
Gson gson = new Gson();
JsonParser parser = new JsonParser();
try{
JsonArray jArray = parser.parse(Tempx.getString("GSON_FEED","")).getAsJsonArray();
for(JsonElement obj : jArray )
{
MainPojo cse = gson.fromJson( obj , MainPojo.class);
TweetList.add(cse);
}
}catch(Throwable e) {
JsonElement obj = parser.parse(Tempx.getString("GSON_FEED","")).getAsJsonObject();
MainPojo cse = gson.fromJson( obj , MainPojo.class);
TweetList.add(cse);
}
Though I am able to log the JSON as String, I don't know if I am storing it the wrong way, any help will be much appreciated, Thanks!
You could define a custom deserializer and register a type adapter with GSON. Also
why are you using this:
JsonArray jArray = parser.parse(Tempx.getString("GSON_FEED","")).getAsJsonArray();
.. when you intend to use GSON for deserialization? You could just do it in your deserializer.
https://sites.google.com/site/gson/gson-user-guide#TOC-Custom-Serialization-and-Deserialization
EG:
public class FooDeserializer implements JsonDeserializer<Foos>
{
#Override public Foos deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException
{
JsonObject jsonObject = json.getAsJsonObject();
JsonArray statusArray = jsonObject.get("statuses").getAsJsonArray();
Foos result = new Foos();
ArrayList fooArray = new ArrayList<>;
for (JsonElement e : statusArray) {
fooArray.add(new Foo());
}
result.setFoos(fooArray);
return result;
}
}

Using Jackson to parse Json map value into String or CustomClass

I'm being given a Json file with the form:
{
"descriptions": {
"desc1": "someString",
"desc2": {"name":"someName", "val": 7.0}
}
}
I have the POJO:
public class CustomClass {
Map<String, Object> descriptions;
public static class NameVal{
String name;
double val;
public NameVal(String name, double val){...}
}
}
I can recreate the json file with the code:
CustomClass a = new CustomClass();
a.descriptions = new HashMap<String, Object>();
a.descriptions.put("desc1", "someString");
a.descriptions.put("desc2", new CustomClass.NameVal("someName", 7.0));
new ObjectMapper().writeValue(new File("testfile"), a);
But, when I read the object back in using:
CustomClass fromFile = new ObjectMapper().readValue(new File("testfile"), CustomClass.class);
then fromFile.descriptions.get("desc2") is of type LinkedHashMap instead of type CustomClass.NameVal.
How can I get Jackson to properly parse the type of the CustomClass.NameVal descriptors (other than making some class that wraps the parsing and explicitly converts the LinkedHashMap after Jackson reads the file)?
Try this. Create a class Description with name and value attributes:
public class Description {
private String name;
private double val;
}
Now in your CustomClass do this:
public class CustomClass {
List<Description> descriptions;
}
And that's it. Remember to create getters and setters because Jackson needs it.
You could try something like this:
public class DescriptionWrapper {
private Description descriptions;
public Description getDescriptions() {
return descriptions;
}
public void setDescriptions(Description descriptions) {
this.descriptions = descriptions;
}
}
public class Description {
private String desc1;
private NameValue desc2;
public String getDesc1() {
return desc1;
}
public void setDesc1(String desc1) {
this.desc1 = desc1;
}
public NameValue getDesc2() {
return desc2;
}
public void setDesc2(NameValue desc2) {
this.desc2 = desc2;
}
}
public class NameValue {
private String name;
private double val;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getVal() {
return val;
}
public void setVal(double val) {
this.val = val;
}
}

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