I have the following JSON to represent the server response for a salt request:
{
"USER":
{
"E_MAIL":"email",
"SALT":"salt"
},
"CODE":"010"
}
And i tried to map it with the following POJO:
public class SaltPOJO {
private String code = null;
private User user = null;
#Override
public String toString() {
return this.user.toString();
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public class User {
private String e_mail = null;
private String salt = null;
#Override
public String toString() {
return this.e_mail + ": " + this.salt;
}
public String getE_mail() {
return e_mail;
}
public void setE_mail(String e_mail) {
this.e_mail = e_mail;
}
public String getSalt() {
return salt;
}
public void setSalt(String salt) {
this.salt = salt;
}
}
}
Now everytime i do this:
Gson gson = new Gson();
SaltPOJO saltPojo = gson.fromJson(json.toString(), SaltPOJO.class);
Log.v("Bla", saltPojo.toString());
The saltPojo.toString() is null. How can i map my JSON into POJO using Gson?
Is the order of my variables important for the Gson mapping?
Is the order of my variables important for the Gson mapping?
No, that's not the case.
How can i map my JSON into POJO using Gson?
It's Case Sensitive and the keys in JSON string should be same as variable names used in POJO class.
You can use #SerializedName annotation to use any variable name as your like.
Sample code:
class SaltPOJO {
#SerializedName("CODE")
private String code = null;
#SerializedName("USER")
private User user = null;
...
class User {
#SerializedName("E_MAIL")
private String e_mail = null;
#SerializedName("SALT")
private String salt = null;
You don't have proper mapping between your getter and setter. If you change your json to something like below, it would work:
{
"user":
{
"email":"email",
"salt":"salt"
},
"code":"010"
}
If you are getting json form third party then unfortunately, you would have to change your pojo or you could use adapter.
Related
I have a JSON String as below:
"{ \"password\":\"des123\",\"ROU_DATA\":[{\"FORM_RECEIVING_TIME\":\"12:00:00\",\"REMARKS\":\"Redemption of Unit\"}, {\"FORM_RECEIVING_TIME\":\"13:00:00\",\"REMARKS\":\"sALE of Unit\"}] }";
Now I want to extract the Array from it and need to use it as a separate pojo class so that I can iterate over each value..
Now the problem is, when I try to convert the complete String to Map and get the Array value from the map.. It transforms its format to MAp format like:
{FORM_RECEIVING_DATE = 12:00:00, etc..}
However json string should be {"FORM_RECEIVING_DATE": "12:00:00", etc..}
due to the MAp format its now allowing me to parse it using my POJO Class..
Please help to convert it to my JSONFormat ...
**NOTE: Please note that I can only use Jackson **.
CLASS A
ObjectMapper mapper2 = new ObjectMapper();
Map<String, Object> map;
map = mapper2.readValue(json, new TypeReference<Map<String, Object>>(){});
System.out.println("map: " + map.get("ROU_DATA") );
String array = map.get("ROU_DATA").toString();
String json2 = new ObjectMapper().writeValueAsString(array.replace("[", "").replace("]", ""));
String json3 = new ObjectMapper().writeValueAsString(json2);
System.out.println("json2>>" + json2);
System.out.println("json2>>" + json3);
mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
// 1. convert JSON array to Array objects
ROU[] pp1 = mapper.readValue("{" + array.replace("=", ":") + "}", ROU[].class);
for (ROU person : pp1) {
System.out.println(person.getRemarks());
}
CLASS B
import com.fasterxml.jackson.annotation.JsonProperty;
public class ROU {
#JsonProperty("FORM_RECEIVING_TIME")
private String formdate;
#JsonProperty("REMARKS")
private String remarks;
public String getFormdate() {
return formdate;
}
public void setFormdate(String formdate) {
this.formdate = formdate;
}
public String getRemarks() {
return remarks;
}
public void setRemarks(String remarks) {
this.remarks = remarks;
}
}
map.get("ROU_DATA") returns a List object, and the toString() method of List does not generate JSON text.
You don't need to convert back to a JSON text just to get the ROU[] created, just call convertValue(...).
String input = "{ \"password\":\"des123\",\"ROU_DATA\":[{\"FORM_RECEIVING_TIME\":\"12:00:00\",\"REMARKS\":\"Redemption of Unit\"}, {\"FORM_RECEIVING_TIME\":\"13:00:00\",\"REMARKS\":\"sALE of Unit\"}] }";
ObjectMapper mapper2 = new ObjectMapper();
Map<?, ?> json = mapper2.readValue(input, Map.class);
ROU[] pp1 = mapper2.convertValue(json.get("ROU_DATA"), ROU[].class);
for (ROU person : pp1)
System.out.println(person.getRemarks());
Output
Redemption of Unit
sALE of Unit
class A
public class ROU {
#JsonProperty("FORM_RECEIVING_TIME")
private String formdate;
#JsonProperty("REMARKS")
private String remarks;
public String getFormdate() {
return formdate;
}
public void setFormdate(String formdate) {
this.formdate = formdate;
}
public String getRemarks() {
return remarks;
}
public void setRemarks(String remarks) {
this.remarks = remarks;
}
}
class B
public class ObjOuter {
private String password;
#JsonProperty("ROU_DATA")
private List<ROU> rous;
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public List<ROU> getRous() {
return rous;
}
public void setRous(List<ROU> rous) {
this.rous = rous;
}
}
json to Object
ObjectMapper mapper = new ObjectMapper();
try {
ObjOuter outer = mapper.readValue(str, ObjOuter.class);
for (ROU rou : outer.getRous()) {
System.out.println(rou.getFormdate());
System.out.println(rou.getRemarks());
}
} catch (IOException e) {
e.printStackTrace();
}
I have the following json from the Server. It is a json array with different objects. I want to identify the user objects based on the key "type" and add them to a user hashmap and fetch user to show information in my view containing the "payments" object. I am using gson and retrofit. TIA
"included":[
{
"id":"1",
"type":"payments",
"attributes":{
"amount_cents":100,
"amount_currency":"INR",
"description":"Test description!!",
"created_at":"2016-03-01T11:30:53Z",
"status":"paid",
"paid_at":null,
"charged_at":null,
"formatted_amount":"Rs1.00"
},
"relationships":{
"sender":{
"data":{
"id":"2",
"type":"users"
}
},
"receiver":{
"data":{
"id":"1",
"type":"users"
}
}
}
},
{
"id":"2",
"type":"users",
"attributes":{
"first_name":"Rob",
"last_name":"Thomas"
}
},
{
"id":"1",
"type":"users",
"attributes":{
"first_name":"Matt",
"last_name":"Thomas"
}
}]
My classes are
public class ActivityFeedItem implements IFeedItem {
#SerializedName("id")
String id;
#SerializedName("type")
String type;
#SerializedName("attributes")
Attributes attributes;
protected class Attributes {
double amount_cents;
String amount_currency;
String description;
String created_at;
String status;
String paid_at;
String charged_at;
String formatted_amount;
Relationships relationships;
public double getAmount_cents() {
return amount_cents;
}
public String getAmount_currency() {
return amount_currency;
}
public String getDescription() {
return description;
}
public String getCreated_at() {
return created_at;
}
public String getStatus() {
return status;
}
public String getPaid_at() {
return paid_at;
}
public String getCharged_at() {
return charged_at;
}
public String getFormatted_amount() {
return formatted_amount;
}
public Relationships getRelationships() {
return relationships;
}
}
}
and
public class UserFeedItem implements IFeedItem {
#SerializedName("id")
String id;
#SerializedName("type")
String type;
#SerializedName("attributes")
Attributes attributes;
public class Attributes {
#SerializedName("first_name")
String first_name;
#SerializedName("last_name")
String last_name;
}
}
This is pretty easy if you just put your JSON response String into a JSONArray. Then you can just access the type field and test if it's users. Like this:
JSONArray jsonArray = new JSONArray(yourServerResponseString);
for(int i=0; i<jsonArray.length(); i++) {
JSONObject object = (JSONObject) jsonArray.get(i);
String type = object.getString("type");
if(type.equals("users")) {
//add to your users HashMap
}
}
First of all create an array of objects from you JSON using GSON as below
Gson gson= new Gson();
String jsonString= yourJsonObject.getString("included");
ActivityFeedItem[] activityFeedArray=gson.fromJson(jsonString,ActivityFeedItem[].class);
Now your activityFeedArray contains all the feedItems you get in JSON. Then you can iterate through it as you would in any array and add to hashmap when type is user as below-
for(ActivityFeedItem item:activityFeedArray) {
if(item.type.equals("users")) {
//add to your users HashMap
}
}
I am trying to read the values of a JSON output.
This is the JSON output:
{"nameOfSummoner":{"id":56529189,"name":"test","profileIconId":550,"summonerLevel":30,"revisionDate":1422110739000}}
And with the following code I am trying to read it:
final Connector connector = new Connector();
String response = connector.connect("link"); // (Returns a String value of the JSON)
final Gson gson = new Gson();
final Summoner summoner = gson.fromJson(response, Summoner.class); //Summoner is a model class
System.out.println(summoner);
Summoner class:
public class Summoner {
private String name;
private long profileIconId;
private long summonerLevel;
private long revisionDate;
public String getName() {
return name;
}
public void setName(final String name) {
this.name = name;
}
public long getProfileIconId() {
return profileIconId;
}
public void setProfileIconId(final long profileIconId) {
this.profileIconId = profileIconId;
}
public long getSummonerLevel() {
return summonerLevel;
}
public void setSummonerLevel(final long summonerLevel) {
this.summonerLevel = summonerLevel;
}
public long getRevisionDate() {
return revisionDate;
}
public void setRevisionDate
(long revisionDate) {
this.revisionDate = revisionDate;
}
#Override
public String toString() {
return "Summoner{" +
"name='" + name + '\'' +
", profileIconId=" + profileIconId +
", summonerLevel=" + summonerLevel +
", revisionDate=" + revisionDate +
'}';
}
}
And I get the following output on the console:
Summoner{name='null', profileIconId=0, summonerLevel=0, revisionDate=0}
I have sadly no idea why this happens. Any help I get is appreciated. I am fairly sure it has to do with the JSON output that "nameOfSummoner" is on top and maybe that's why it does not read what is below.
As mentioned by #PeterMmm , your input is a map with 1 key-value pair.
You need to Create another POJO with Summoner object as attribute:
public class Sample {
private Summoner nameOfSummoner;
//getters and setters
}
and then try parsing. Or, you could create a Map and parse.
Map<String, Summoner> responseObj = new HashMap<String, Summoner>();
responseObj= gson.fromJson(response, responseObj.class);
Summoner obj = responseObj.get("nameOfSummoner");
You will also need to have "id" attribute in Summoner class I believe, else gson will throw an exception.
i get a JSON response from a server and i want to transform it into a POJO which is the following:
public class MeasureDataGetPOJO {
#SerializedName("CODE")
private String code = null;
#SerializedName("USER")
private User user = null;
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public class User {
private List<MeasureData> measureDatas = null;
public List<MeasureData> getMeasureDatas() {
return measureDatas;
}
public void setMeasureDatas(List<MeasureData> measureDatas) {
this.measureDatas = measureDatas;
}
public class MeasureData {
#SerializedName("MT_TIME")
private String time = null;
#SerializedName("MT_VALUE")
private String value = null;
public String getTime() {
return time;
}
public void setTime(String time) {
this.time = time;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
}
}
The JSON i get from the server:
{
"CODE":"012",
"USER":
[
{
"MT_TIME":"1412882760",
"MT_VALUE":"319",
}
]
}
And the error i get from Gson is:
Caused by: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 10
Is there something wrong with the JSON or with the POJO i try to map the JSON into?
I am expecting one user with multiple pairs of MT_TIME and MT_VALUE.
So i get a status code and a user object. the user has a array of pairs of MT_TIME and MT_VALUE.
Later there maybe will be more user informations in the user object.
It is just a guess but would this be the correct json?
{
"CODE":"012",
"USER":
{
"MEASURE_DATA":
[
{
"MT_TIME":"1412882760",
"MT_VALUE":"319"
}
]
}
}
with an additional SerializedName here:
#SerializedName("MEASURE_DATA")
private List<MeasureData> measureDatas = null;
It is expected. From what your class says, the JSON should look like:
{
"CODE": "012",
"USER": {
"MT_TIME": "1412882760",
"MT_VALUE": "319",
}
}
But the user field in the JSON you showed is inside an array.
If this means that what you expect is a list of users instead of just one user, then replace your field in the POJO with a List<User>; otherwise, fix the JSON.
You need list of Users. See that after "USER": there is a [ in your json String.
This is what the error is saying:
Expected BEGIN_OBJECT but was BEGIN_ARRAY
I have integrated Gson to create the json used in a request for an android application.
Here is my model class
public class TwitterUser {
#Expose
public String gid;
public String icon_url;
public Boolean is_app_user;
#Expose
public String displayName;
public TwitterUser(String l, String i, String url, Boolean app_user) {
gid = i;
displayName = l;
icon_url = url;
is_app_user = app_user;
}
public TwitterUser(String l, String i) {
gid = i;
displayName = l;
}
public String getGid() {
return gid;
}
public void setGid(String gid) {
this.gid = gid;
}
public String getIcon_url() {
return icon_url;
}
public void setIcon_url(String icon_url) {
this.icon_url = icon_url;
}
public Boolean getIs_app_user() {
return is_app_user;
}
public void setIs_app_user(Boolean is_app_user) {
this.is_app_user = is_app_user;
}
public String getDisplayName() {
return displayName;
}
public void setDisplayName(String displayName) {
this.displayName = displayName;
}
Here is how i create the json request
Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();
gson.toJson(twitterUser));
But when I send the request to the server - the order will be rejected. I have to change the request's field order to stay:
gid
displayName
but gson creates other way around, is there any way to achieve this.
Gson doesn't support definition of property order out of the box, but there are other libraries that do. Jackson allows defining this with #JsonPropertyOrder, for example.
But of course Gson has it's way so you can do it by creating your very own Json serializer:
public class TwitterUserSerializer implements JsonSerializer<TwitterUser> {
#Override
public JsonElement serialize(TwitterUser twitterUser, Type type, JsonSerializationContext context) {
JsonObject object = new JsonObject();
object.add("gid", context.serialize(twitterUser.getGid());
object.add("displayName", context.serialize(twitterUser.getDisplayName());
// ...
return object;
}
}
Then of course you need to pass this serializer to Gson during Setup like this:
Gson gson = new GsonBuilder().registerTypeAdapter(TwitterUser.class, new TwitterUserSerializer()).excludeFieldsWithoutExposeAnnotation().create();
String json = gson.toJson(twitterUser);
See also:
Gson User Guide - Custom serializers and deserializers