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Jackson exception: Could not resolve type id as a subtype of

I'm trying to parse following JSON string with one field inside. Unfortunatelly still getting exception:
InvalidTypeIdException: Could not resolve type id 'pin' as a subtype of `com.example.dto.AuthorizationRequest`: known type ids = [AuthorizationRequest]
Here is base class:
#JsonTypeInfo(include = JsonTypeInfo.As.WRAPPER_OBJECT ,use = JsonTypeInfo.Id.NAME)
#JsonSubTypes({
#JsonSubTypes.Type(value = AuthorizationRequest.class, name = "AuthorizationRequest")})
public interface IMessage {}
Derived class:
public class AuthorizationRequest implements IMessage {
#JsonProperty( value = "pin", required = true )
private String pin;
public String getPin() {
return pin;
}
public void setPin(String pin) {
this.pin = pin;
}
}
Test:
#Test
void test(){
String request =
"{\n"
+ " \"AuthorizationRequest\": {\n"
+ " \"pin\": \"1234\"\n"
+ " }\n"
+ "}";
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
AuthorizationRequest authorizationRequest = null;
try {
authorizationRequest = objectMapper.readValue(request, AuthorizationRequest.class);
} catch (JsonProcessingException e) {
throw new RuntimeException(e);
}
}
What am I missing? I need to use request name as json root element.

You can delete objectMapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true) line. The error is due to the fact that the line unwraps the initial object so escalating of one level at the intern of the json file obtaining the {"pin" : "1234"} json with the ""AuthorizationRequest" label. The JsonTypeInfo.As.WRAPPER_OBJECT annotation indicates to the jackson library to escalate again of one level the json file so obtaining the "1234" string labelled by "pin".The JsonTypeInfo.Id.NAME compares the "pin" string with the names of subclasses and because of it fails causing the issue and the error message.

Not able to map Json to java Object using Jackson and lombok

POJOs:
import lombok.Data;
#Data
public class CCMTRequest {
private MOEH cch;
private String filler1;
private CCMTCCD ccd;
private String uPwName;
}
#Data
public class MOEH {
private String c;
private int z;
private String dType;
}
#Data
public class CCMTCCD {
private dTime time;
private int x;
}
#Data
public class dTime {
private String dTime;
}
Test Class:
public class TestJacksonParser {
#Test
void load_jsonToPOJO() {
ObjectMapper mapper = new ObjectMapper();
ClassLoader load = this.getClass().getClassLoader();
File file = new File(load.getResource("request.json").getFile());
CCMTRequest req = null;
try {
req = mapper.readValue(file, CCMTRequest.class);
}
catch(Exception e) {
System.out.println(e.getMessage());
}
System.out.println("\nRequest: " + req);
}
}
request.json :
{
"cch" : {
"c" : "C",
"z" : 4678,
"dType" : "dtype"
},
"filler1" : "random filler1",
"ccd" : {
"time" : {
"dTime" : "4:35"
},
"x" : 34567
},
"uPwName" : "uPwName"
}
Error:
Unrecognized field "dType" (class com.spring.mapstruct.test.MOEH), not
marked as ignorable (3 known properties: "z", "c", "dtype"]) at
[Source: (File); line: 5, column: 14] (through reference chain:
com.spring.mapstruct.test.CCMTRequest["cch"]->com.spring.mapstruct.test.MOEH["dType"])
Request: null
Now, when I update my test class as :
public class TestJacksonParser {
#Test
void load_jsonToPOJO() {
ObjectMapper mapper = new ObjectMapper();
//ignore Unknown JSON Fields
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
ClassLoader load = this.getClass().getClassLoader();
File file = new File(load.getResource("request.json").getFile());
CCMTRequest req = null;
try {
req = mapper.readValue(file, CCMTRequest.class);
}
catch(Exception e) {
System.out.println(e.getMessage());
}
System.out.println("\nRequest: " + req);
}
}
I get output as:
Request: CCMTRequest(cch=MOEH(c=C, z=4678, dType=null), filler1=random
filler1, ccd=CCMTCCD(time=dTime(dTime=4:35), x=34567), uPwName=null)
So how jackson is working here with lombok, is there an issue with properties "dType" and "uPwName" ?

first things first, next time please provide better example rather than random name properties. it's confusing.
your problem is because lombok generate getter and setter for property like "uPwName" becomes "getUPwName()" and "setUPwName()". jackson read it as "getuPwName" and "setuPwName";
the library both using different naming convention for getters and setters.
there are 2 approach to fix this:
for your quick fix:
ObjectMapper mapper = new ObjectMapper().disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)
.enable(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES);
for better way to fix your problem: use better name for your properties.

Issue converting from JSON to POJO using Gson

I have a JSON REST endpoint response and I wanted to get the value of hotelNbr from it. How do i do it ?
{
"found": [
{
"hotelNbr": 554050442,
"hotelAddress": "119 Maven Lane, New Jersey",
}
],
"errors": []
}
I am using the below code to get it but it fails in below mentioned line:
public List<Hotel> RDS_POST_HotelDetails(String HotelName, String sUrl) throws Exception, IOException {
Gson gson = new GsonBuilder().setPrettyPrinting().create();
// Create your http client
CloseableHttpClient httpclient = HttpClientBuilder.create().build();
// Create http Put object
HttpPost ohttppost = new HttpPost(sUrl);
// Message Body
StringEntity input = new StringEntity(
"{\"hotelNbr\":[\""+HotelName+"\" ]}"
);
// Set content type for post
input.setContentType("application/json");
// attach message body to request
ohttppost.setEntity(input);
// submit request and save response
HttpResponse response = httpclient.execute(ohttppost);
// Get response body (entity and parse to string
String sEntity = EntityUtils.toString(response.getEntity());
List<Hotel> hotelobject = new ArrayList<Hotel>();
// Create a type token representing the type of objects in your json response
// I had to use the full class path of TYPE because we also have a Type class in our project
java.lang.reflect.Type cType = new TypeToken<List<Hotel>>() {
}.getType();
// Convert to Array object using gson.fromJson(<json string>,
// <type>)
hotelObject = gson.fromJson(sEntity, cType); // I am getting error here
String hotelNumber = hotelObject.get(0).getFound().get(0).getItemNbr().toString();
}
Please find the Hotel.java class below
package com.hotels.company;
import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;
public class Hotel {
#SerializedName("found")
#Expose
private List<Found> found = null;
#SerializedName("errors")
#Expose
private List<Object> errors = null;
public List<Found> getFound() {
return found;
}
public void setFound(List<Found> found) {
this.found = found;
}
public List<Object> getErrors() {
return errors;
}
public void setErrors(List<Object> errors) {
this.errors = errors;
}
}
Please find Found.java class below :
package com.hotels.company;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;
public class Found {
#SerializedName("hotelNbr")
#Expose
private Integer hotelNbr;
#SerializedName("hotelAddress")
#Expose
private String hotelAddress;
public Integer getHotelNbr() {
return hotelNbr;
}
public void setHotelNbr(Integer hotelNbr) {
this.hotelNbr = hotelNbr;
}
public String getHotelAddress() {
return hotelAddress;
}
public void setHotelAddress(String hotelAddress) {
this.hotelAddress = hotelAddress;
}
}
I tried finding some examples in StackOverflow questions but didn't get solution for mine. Any help will be appreciated.

The JSON you are parsing is not well formatted..
There is a comma after "hotelAddress" remove that
Correct JSON would be:
{
"found":[
{
"hotelNbr":554050442,
"hotelAddress":"119 Maven Lane, New Jersey"
}
],
"errors":[ ]
}

I found a couple of issues:
Json is not valid. Observe there is a comma at the end of "hotelAddress": "119 Maven Lane, New Jersey",. Remove it.
You are trying to deserialize the json into List<Hotel>, but the json mentioned is not a list. Either update the json or deserialise it into Hotel object instead of List.

Java REST service. Info is not saved to file and my code doesnt read the file

I am creating my first Rest service using JSON objects for the data
transfer between user and server, with the help of the Gson library 2.5.
I am not using any frameworks like Jersey or anything like that. (That was my
project requirment). The java version i use is 1.6 (part of my requirment)
jboss server and Eclipse as IDE.
At the moment i have 2 small functions from a simple HTML form. The first is
suposed to requests the data from the JSON file and the second is suposed to
add a new json information to the json document.
Problem is: When i try to acces the JSON file, a array its returned with the
last submited Person. When i save a new Person information, that information is
not saved in the personsJsonFile but someplace else [have no ideea where].
My json file is found in the Projects main folder.
Any help is deeply apreciated.
GetData class:
#Path("/data")
public class GetDataClass {
#GET
#Produces("text/plain")
public ArrayList<PersonConstructor> displayJsonFile() throws IOException{
ArrayList<PersonConstructor> newLib = new ArrayList<PersonConstructor>();
File jsonFile = new File("personsJsonFile.json");
Scanner fileInput = new Scanner(jsonFile);
Gson gson = new Gson();
while(fileInput.hasNextLine()){
String jsonLine = fileInput.nextLine();
PersonConstructor singlePerson = gson.fromJson(jsonLine, PersonConstructor.class);
newLib.add(singlePerson);
}
fileInput.close();
return newLib;
}
}
AddData Class:
#Path("/add")
public class AddPersonsClass {
#POST
public String addPersons(
#FormParam("idInput") int idInput,
#FormParam("surnameInput") String surnameInput,
#FormParam("nameInput") String nameInput
) throws IOException
{
Gson gson = new Gson();
PersonConstructor newPerson = new PersonConstructor();
newPerson.setPersonId(idInput);
newPerson.setPersonNume(nameInput);
newPerson.setPersonPrenume(surnameInput);
File jsonFile = new File("personsJsonFile.json");
FileWriter jsonWriter = new FileWriter(jsonFile);
System.out.println(newPerson);
String jsonLine = gson.toJson(newPerson);
System.out.println(newPerson);
jsonWriter.write(jsonLine+"\n");
jsonWriter.close();
return "Element: " + newPerson + "has been added";
}
}
PersonConstructor Class:
public class PersonConstructor {
private int personId;
private String personNume;
private String personPrenume;
public PersonConstructor(int personId, String personNume,String personPrenume){
this.personId = personId;
this.personPrenume = personPrenume;
this.personNume = personNume;
}
public PersonConstructor() {
}
public int getPersonId(){
return personId;
}
public void setPersonId(int personId){
this.personId = personId;
}
public String getPersonNume(){
return personNume;
}
public void setPersonNume(String personNume){
this.personNume = personNume;
}
public String getPersonPrenume(){
return personPrenume;
}
public void setPersonPrenume(String personPrenume){
this.personPrenume = personPrenume;
}
public String toString(){
return String.format("\n%s %s %s\n", this.personId, this.personNume, this.personPrenume);
}
}
Json file contains:
{"personId":5,"personNume":"Ursu","personPrenume":"Niculae"},
{"personId":6,"personNume":"Ivan","personPrenume":"Claudiu"},
{"personId":7,"personNume":"Hap","personPrenume":"Dorel"}

Your problem seems to that you have not specified the path where to save the file.
Add the path when creating a file.
final String jsonDirectory = "path to file";
File file = new File(jsonDirectory + "\\results.txt");

nested for each loop to store data in json object

I am trying to store the data into json object in the below format:
{"mobile:":[{"price":"Rs. abc","name":"def"},{"price":"Rs. ghi","name":"jkl"},....}]}
I am trying in the below way but iam not getting desired output code is below:
Elements mobilename = document.select(
"#products div.product-unit div.pu-title ");
Elements price = document.select(
"#products div.product-unit div.pu-price div.pu-final span.fk-font-17");
for(Element url1:mobilename)
{
text=url1.text();
System.out.println(text);
for(Element b:price)
{
text1= b.text();
System.out.println(text1);
arr1.add(text1);
arr1.add(text);
}
pa.put("price",text1 );
pa.put("name", text);
obj7.add(pa);
}
json.put("mobile:", obj7);
I am getting the same mobile name and price in all the arrays.
Thank You.

I would use Jackson mapper for this. You can find it here
import com.fasterxml.jackson.databind.ObjectMapper;
public static class YourObject {
private List<Mobile> mobile;
// add getter + setter for mobile
}
public static class Mobile {
private String price;
private String name;
// add getter+setter for price and name
}
YourObject obj = new YourObject();
obj.setMobile(new Mobile[] { new Mobile("price1", "name1"), new Mobile("price2", "name2") });
ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeValueAsString(obj);