Develop Reference

jackson deserialize wrapped array

I got the following JSON that im trying to deserialize:
{
"items": [
{
"id": 29000012,
"name": "Crystal League I",
"iconUrls": {
"small": "https://api-assets.clashofclans.com/leagues/72/kSfTyNNVSvogX3dMvpFUTt72VW74w6vEsEFuuOV4osQ.png",
"tiny": "https://api-assets.clashofclans.com/leagues/36/kSfTyNNVSvogX3dMvpFUTt72VW74w6vEsEFuuOV4osQ.png",
"medium": "https://api-assets.clashofclans.com/leagues/288/kSfTyNNVSvogX3dMvpFUTt72VW74w6vEsEFuuOV4osQ.png"
}
},
{
"id": 29000015,
"name": "Master League I",
"iconUrls": {
"small": "https://api-assets.clashofclans.com/leagues/72/olUfFb1wscIH8hqECAdWbdB6jPm9R8zzEyHIzyBgRXc.png",
"tiny": "https://api-assets.clashofclans.com/leagues/36/olUfFb1wscIH8hqECAdWbdB6jPm9R8zzEyHIzyBgRXc.png",
"medium": "https://api-assets.clashofclans.com/leagues/288/olUfFb1wscIH8hqECAdWbdB6jPm9R8zzEyHIzyBgRXc.png"
}
}
],
"paging": {
"cursors": {}
}}
Im trying to deserialize it with the following DTO:
#JsonRootName("items")
#JsonIgnoreProperties(value={ "paging" })
public class League {
private Long id;
private String name;
private IconUrls iconUrls;
public League() {
}
}
class IconUrls {
private String small;
private String tiny;
private String medium;
public IconUrls() {
}
}
But im getting the following error:
com.fasterxml.jackson.databind.exc.MismatchedInputException: Root name ('items') does not match expected ('List') for type `java.util.List<gg.stats.wrapper.entities.League>
I have also set: DeserializationFeature.UNWRAP_ROOT_VALUE
This is the call of the method from my Client:
List<League> getLeagueList();
The problem might be the "paging" key.
Any workaround for that?

I actually found a solution by myself:
#JsonIgnoreProperties(value={ "paging" }, allowGetters=true)
public class ResponseWrapper<T> {
private List<T> items;
#JsonProperty("items")
public List<T> getResponseContent() {
return this.items;
}
#JsonProperty("items")
public void setResponseContent(List<T> items) {
this.items = items;
}
}

How can I match search result in Elasticsearch to the Java Model?

Firstly, my project has MinIO server where I use minio api to upload my files via spring boot application. The MinIO server integrated with Elasticsearch. When I uploaded a file, MinIO automatically update Elasticsearch minio_events index (I have configured this settings before). I want to run following query in my spring boot application and match result into File.java:
POST http://localhost:9200/minio_events/_search
{
"query": {
"bool": {
"must": [
{
"match": {
"Records.s3.object.userMetadata.X-Amz-Meta-Filename": "myfile.txt"
}
},
{
"match": {
"Records.s3.object.userMetadata.X-Amz-Meta-User_id": "40b3c4e0-fea8-4aca-9dec-b4b905f33df0"
}
}
]
}
},
"fields": [
"Records.s3.object.userMetadata.X-Amz-Meta-Filename",
"Records.s3.object.userMetadata.X-Amz-Meta-Description",
"Records.s3.object.userMetadata.X-Amz-Meta-Foldername",
"Records.s3.object.userMetadata.X-Amz-Meta-Tags",
"Records.s3.object.userMetadata.X-Amz-Meta-User_id"
],
"_source": false
}
The query result is:
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1.7260925,
"hits": [
{
"_index": "minio_events",
"_type": "_doc",
"_id": "AUuxte4_W8625RK6e6oT7tCJmJkSQJ0L9LGx6eAf0Dw=",
"_score": 1.7260925,
"fields": {
"Records.s3.object.userMetadata.X-Amz-Meta-Foldername": [
"helloworld"
],
"Records.s3.object.userMetadata.X-Amz-Meta-Description": [
"des"
],
"Records.s3.object.userMetadata.X-Amz-Meta-User_id": [
"40b3c4e0-fea8-4aca-9dec-b4b905f33df0"
],
"Records.s3.object.userMetadata.X-Amz-Meta-Filename": [
"MyFile.txt"
],
"Records.s3.object.userMetadata.X-Amz-Meta-Tags": [
"hello,world"
]
}
}
]
}
}
In my Spring Boot App, I wrote following repository class to fetch Elasticsearch results.
CustomFileRepository.java:
package com.oktaykcr.fileservice.repository;
import com.oktaykcr.fileservice.model.File;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
import org.springframework.data.elasticsearch.core.SearchHit;
import org.springframework.data.elasticsearch.core.SearchHits;
import org.springframework.data.elasticsearch.core.query.NativeSearchQuery;
import org.springframework.data.elasticsearch.core.query.Query;
import org.springframework.stereotype.Component;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
#Component
public class CustomFileRepository {
private final ElasticsearchOperations elasticsearchOperations;
private final List<String> fields = List.of(
"Records.s3.object.userMetadata.X-Amz-Meta-Filename",
"Records.s3.object.userMetadata.X-Amz-Meta-Description",
"Records.s3.object.userMetadata.X-Amz-Meta-Foldername",
"Records.s3.object.userMetadata.X-Amz-Meta-Tags",
"Records.s3.object.userMetadata.X-Amz-Meta-User_id"
);
public CustomFileRepository(ElasticsearchOperations elasticsearchOperations) {
this.elasticsearchOperations = elasticsearchOperations;
}
public List<File> findByFileNameAndUserId(String fileName, String userId) {
BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery()
.must(QueryBuilders.matchQuery("Records.s3.object.userMetadata.X-Amz-Meta-Filename", fileName))
.must(QueryBuilders.matchQuery("Records.s3.object.userMetadata.X-Amz-Meta-User_id", userId));
Query query = new NativeSearchQuery(queryBuilder);
query.setFields(fields);
SearchHits<File> result = elasticsearchOperations.search(query, File.class);
if(result.isEmpty()) {
return Collections.emptyList();
}
List<File> files = result.getSearchHits().stream().map(SearchHit::getContent).collect(Collectors.toList());
return files;
}
}
File.java:
package com.oktaykcr.fileservice.model;
import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;
import org.springframework.data.elasticsearch.annotations.Field;
import org.springframework.data.elasticsearch.annotations.FieldType;
import java.util.List;
#Document(indexName = "minio_events")
public class File {
#Id
private String id;
#Field(type = FieldType.Object, value = "fields")
private Fields fields;
public File() {
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Fields getFields() {
return fields;
}
public void setFields(Fields fields) {
this.fields = fields;
}
static class Fields {
#Field(type = FieldType.Nested, value = "Records.s3.object.userMetadata.X-Amz-Meta-Foldername")
public List<String> folderName;
#Field(type = FieldType.Nested, value = "Records.s3.object.userMetadata.X-Amz-Meta-Description")
public List<String> description;
#Field(type = FieldType.Nested, value = "Records.s3.object.userMetadata.X-Amz-Meta-User_id")
public List<String> userId;
#Field(type = FieldType.Nested, value = "Records.s3.object.userMetadata.X-Amz-Meta-Filename")
public List<String> fileName;
#Field(type = FieldType.Nested, value = "Records.s3.object.userMetadata.X-Amz-Meta-Tags")
public List<String> tags;
public Fields() {
}
public List<String> getFolderName() {
return folderName;
}
public void setFolderName(List<String> folderName) {
this.folderName = folderName;
}
public List<String> getDescription() {
return description;
}
public void setDescription(List<String> description) {
this.description = description;
}
public List<String> getUserId() {
return userId;
}
public void setUserId(List<String> userId) {
this.userId = userId;
}
public List<String> getFileName() {
return fileName;
}
public void setFileName(List<String> fileName) {
this.fileName = fileName;
}
public List<String> getTags() {
return tags;
}
public void setTags(List<String> tags) {
this.tags = tags;
}
}
}
However, the result of List<File> files = customFileRepository.findByFileNameAndUserId(fileName, userId); is:
result = {ArrayList#15401} size = 1
0 = {File#15403}
id = "AUuxte4_W8625RK6e6oT7tCJmJkSQJ0L9LGx6eAf0Dw="
fields = null
id was mapped by #Document model but fields was not.

Java mapping JSON with POJO using jackson

I want to create this JSON using jakson annotated POJOS. The issue I have when I create a new class without #JsonProperty annotation to represent the last {"id":"123ccc","role":"dddd"}, it by default take the class name and create something like "customer":{"id": "123ccc","role":"dddd"}.
The JSON Structure I indent to build
{
"relatedParty": [
{
"contact": [
{
"mediumType": "xxx",
"characteristic": {
"city": "xxx",
"country": "xxx"
}
},
{
"mediumType": "yyy",
"characteristic": {
"emailAddress": "yyy#yy.yyy"
}
}
],
"role": "ccc",
"fullName": "ccc"
},
{
"id": "123ccc",
"role": "dddd"
}
]
}
The JSON I'm receiving from the below code.
{
"relatedParty": [
{
"contact": [
{
"mediumType": "xxx",
"characteristic": {
"city": "xxx",
"country": "xxx"
}
},
{
"mediumType": "yyy",
"characteristic": {
"emailAddress": "yyy#yy.yyy"
}
}
],
"role": "ccc",
"fullName": "ccc"
},
"customer" : {
"id": "123ccc",
"role": "dddd"
}
]
}
What would be a workaround to get the exact JSON format as the image. Current Implementation is below.
import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.List;
public class RelatedParty {
#JsonProperty(value = "contact")
private List<Contact> contact;
#JsonProperty(value = "role")
private String role;
#JsonProperty(value = "fullName")
private String fullName;
private Customer customer;
public List<Contact> getContact() {
return contact;
}
public void setContact(List<Contact> contact) {
this.contact = contact;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
public String getFullName() {
return fullName;
}
public void setFullName(String fullName) {
this.fullName = fullName;
}
public Customer getCustomer() {
return customer;
}
public void setCustomer(Customer customer) {
this.customer = customer;
}
}
public class Customer {
#JsonProperty(value = "id")
private String id;
#JsonProperty(value = "role")
private String role;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
}

You need to create additional and different POJO classes to model your JSON correctly. Basically, JSON arrays will be handle in Java lists, and JSON objects will be handled in Java classes.
Starting from the inside (most nested level) of the JSON, and working our way out:
NOTE: getters and setters not shown here
Characteristic.java
#JsonInclude(JsonInclude.Include.NON_NULL)
public class Characteristic {
#JsonProperty("city")
private String city;
#JsonProperty("country")
private String country;
#JsonProperty("emailAddress")
private String emailAddress;
}
Contact.java (contains our characteristics):
#JsonInclude(JsonInclude.Include.NON_NULL)
public class Contact {
#JsonProperty("mediumType")
private String mediumType;
#JsonProperty("characteristic")
private Characteristic characteristic;
}
The above two classes handle the innermost objects. If we remove them from your target JSON, that leaves the following:
{
"relatedParty": [{
"contact": [...],
"role": "ccc",
"fullName": "ccc"
}, {
"role": "dddd",
"id": "123ccc"
}]
}
Note that the contact field is a JSON array, not an object - so we do not create a Java Contact class (which would be for a JSON object).
To handle the above I create two more classes:
RelatedPartyInner.java (contains a list of contacts)
#JsonInclude(JsonInclude.Include.NON_NULL)
public class RelatedParty_ {
#JsonProperty("contact")
private List<Contact> contact = null;
#JsonProperty("role")
private String role;
#JsonProperty("fullName")
private String fullName;
#JsonProperty("id")
private String id;
}
RelatedParty.java (wraps everything in an outer object):
#JsonInclude(JsonInclude.Include.NON_NULL)
public class RelatedParty {
#JsonProperty("relatedParty")
private List<RelatedPartyInner> relatedParty = null;
}
To test this I create the following data:
Characteristic chr1 = new Characteristic();
chr1.setCity("xxx");
chr1.setCountry("xxx");
Characteristic chr2 = new Characteristic();
chr2.setEmailAddress("yyy#yy.yyy");
Contact con1 = new Contact();
con1.setMediumType("xxx");
con1.setCharacteristic(chr1);
Contact con2 = new Contact();
con2.setMediumType("yyy");
con2.setCharacteristic(chr2);
List<Contact> cons = new ArrayList<>();
cons.add(con1);
cons.add(con2);
RelatedPartyInner rpi1 = new RelatedPartyInner();
rpi1.setContact(cons);
rpi1.setRole("ccc");
rpi1.setFullName("ccc");
RelatedPartyInner rpi2 = new RelatedPartyInner();
rpi2.setId("123ccc");
rpi2.setRole("dddd");
List<RelatedPartyInner> rpis = new ArrayList<>();
rpis.add(rpi1);
rpis.add(rpi2);
RelatedParty rp = new RelatedParty();
rp.setRelatedParty(rpis);
Finally, we can generate the JSON:
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.writeValue(new File("rp.json"), rp);
The resulting file contains the following:
{
"relatedParty": [{
"contact": [{
"mediumType": "xxx",
"characteristic": {
"city": "xxx",
"country": "xxx"
}
}, {
"mediumType": "yyy",
"characteristic": {
"emailAddress": "yyy#yy.yyy"
}
}],
"role": "ccc",
"fullName": "ccc"
}, {
"role": "dddd",
"id": "123ccc"
}]
}

Aggregation results cannot properly map to Java object

I'm trying to get schedules data from mongoDb.
I created the appropriate aggregation and tried to convert it within Spring Framework.
db.theaters.aggregate([
{ $match: { 'city_id': <someCityId>, 'theatreRooms.schedules.spectacle_id': <someSpecId> } },
{ $unwind: '$theatreRooms' },
{ $unwind: '$theatreRooms.schedules' },
{ $group: { _id: { name: '$name', room: '$theatreRooms.name' }, schedules: { $addToSet: '$theatreRooms.schedules.time' } } },
{ $group: { _id: '$_id.name', schedules: { $addToSet: { room: '$_id.room', schedules: '$schedules' } } } }
])
I've created properly match and unwind operations. But I've got problem with first group operation.
It seems that the operation is well interpreted, but for some reason I am not able to properly map the _id object.
Here is my code example:
public class TheaterProject {
private TheaterId _id;
private List<String> schedules;
public TheaterId get_id() {
return _id;
}
public void set_id(TheaterId _id) {
this._id = _id;
}
public List<String> getSchedules() {
return schedules;
}
public void setSchedules(List<String> schedules) {
this.schedules = schedules;
}
}
public class TheaterId {
#Field("name")
private String name;
#Field("room")
private Integer room;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getRoom() {
return room;
}
public void setRoom(Integer room) {
this.room = room;
}
}
public Document getRawSchedules(String cityId, String spectaclesId){
MatchOperation match = Aggregation.match(Criteria.where("city_id").is(cityId).and("theatreRooms.schedules.spectacle_id").is(spectaclesId));
UnwindOperation theaterUnwind = Aggregation.unwind("theatreRooms");
UnwindOperation schedulesUnwind = Aggregation.unwind("theatreRooms.schedules");
GroupOperation firstGroup = Aggregation.group(Fields.from(
Fields.field("name", "name"),
Fields.field("room", "theatreRooms.name")))
.addToSet("theatreRooms.schedules.time").as("schedules");
Aggregation agg = Aggregation.newAggregation(match,theaterUnwind,schedulesUnwind,firstGroup);
Document theaters = mongoTemplate.aggregate(agg, Theater.class, TheaterProject.class).getRawResults();
return theaters;
}
public List<TheaterProject> getSchedules(String cityId, String spectaclesId){
MatchOperation match = Aggregation.match(Criteria.where("city_id").is(cityId).and("theatreRooms.schedules.spectacle_id").is(spectaclesId));
UnwindOperation theaterUnwind = Aggregation.unwind("theatreRooms");
UnwindOperation schedulesUnwind = Aggregation.unwind("theatreRooms.schedules");
GroupOperation firstGroup = Aggregation.group(Fields.from(
Fields.field("name", "name"),
Fields.field("room", "theatreRooms.name")))
.addToSet("theatreRooms.schedules.time").as("schedules");
Aggregation agg = Aggregation.newAggregation(match,theaterUnwind,schedulesUnwind,firstGroup);
List<TheaterProject> theaters = mongoTemplate.aggregate(agg, Theater.class, TheaterProject.class).getMappedResults();
return theaters;
}
When I've invoked method getSchedules which return mapped objects, _id field is equal to null.
[
{
"_id": null,
"schedules": [
"5:15"
]
},
{
"_id": null,
"schedules": [
"6:55",
"4:35",
"10:15"
]
}
]
But when I've invoked getRawSchedules which used getRawResults it's looking properly.
{
"results": [
{
"_id": {
"name": "Pinokio",
"room": 2
},
"schedules": [
"5:15"
]
},
{
"_id": {
"name": "Roma",
"room": 1
},
"schedules": [
"6:55",
"4:35",
"10:15"
]
}
]
}
I don't have any idea why it's working like that.

I didn't find any information about this problem in the documentation and here. But I have a solution. You may just rename the field from _id to something else. theaterId for example. I don't know all requirements for your issue but you may do it just on mapping level.
Fix the mapping
import org.springframework.data.mongodb.core.mapping.Field;
import java.util.List;
public class TheaterProject {
#Field("theaterId")
private TheaterId _id;
private List<String> schedules;
public TheaterId get_id() {
return _id;
}
public void set_id(TheaterId _id) {
this._id = _id;
}
public List<String> getSchedules() {
return schedules;
}
public void setSchedules(List<String> schedules) {
this.schedules = schedules;
}
}
But it requires additional projection step
public List<TheaterProject> getSchedules(String cityId, String spectaclesId){
...
GroupOperation firstGroup = Aggregation.group(Fields.from(
Fields.field("name", "name"),
Fields.field("room", "theatreRooms.name")))
.addToSet("theatreRooms.schedules.time").as("schedules");
ProjectionOperation projection = Aggregation.project(Fields.from(
Fields.field("theaterId", "_id"),
Fields.field("schedules", "schedules")));
Aggregation agg = Aggregation.newAggregation( ... ,firstGroup, projection);
List<TheaterProject> theaters = mongoTemplate.aggregate(agg, "collectionName", TheaterProject.class).getMappedResults();
return theaters;
}

How to implement customized serialization feature in fasterxml

My JSON:
{
"name": "asdf",
"age": "15",
"address": {
"street": "asdf"
}
}
If street is null, with JsonSerialize.Inclusion.NON_NULL, I can get..
{
"name": "asdf",
"age": "15",
"address": {}
}
But I want to get something like this.. (when address is not null, it is a new/empty object. But street is null.)
{
"name": "asdf",
"age": "15"
}
I thought to have custom serialization feature like JsonSerialize.Inclusion.VALID_OBJECT.
Adding isValid() method in the Address class then if that returns true serialize else don't serialize.
But I don't know how to proceed further/which class to override. Is this possible or any other views on this? Please suggest.
Added classes
public static void main(String[] args) {
ObjectMapper mapper = new ObjectMapper();
Customer customer = new Customer();
customer.setName("name");
customer.setAddress(new Address());
mapper.writeValue(new File("d:\\customer.json"), customer);
}
#JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class Customer {
private String name;
private Address address;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
}
#JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class Address {
private String street;
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
}
Note: I am not worrying about deserialization now. i.e, loss of address object.
Thanks in advance.

Customized JSON Object using Serialization is Very Simple.
I have wrote a claas in my project i am giving u a clue that how to Implement this in Projects
Loan Application (POJO Class)
import java.io.Serializable;
import java.util.List;
import org.webservice.business.serializer.LoanApplicationSerializer;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
#JsonSerialize(using=LoanApplicationSerializer.class)
public class LoanApplication implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private double amount;
private User borrowerId;
private String businessType;
private String currency;
private int duration;
private Date lastChangeDate;
private long loanApplicationId;
private String myStory;
private String productCategory;
private String purpose;
private Date startDate;
private String status;
private String type;
private String salesRepresentative;
Now LoanApplicationSerializer class that contains the Customization using Serialization Logic................
package org.ovamba.business.serializer;
import java.io.IOException;
import org.webservice.business.dto.LoanApplication;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
public class LoanApplicationSerializer extends JsonSerializer<LoanApplication> {
#Override
public void serialize(LoanApplication prm_objObjectToSerialize, JsonGenerator prm_objJsonGenerator, SerializerProvider prm_objSerializerProvider) throws IOException, JsonProcessingException {
if (null == prm_objObjectToSerialize) {
} else {
try {
prm_objJsonGenerator.writeStartObject();
prm_objJsonGenerator.writeNumberField("applicationId", prm_objObjectToSerialize.getLoanApplicationId());
prm_objJsonGenerator.writeStringField("status", prm_objObjectToSerialize.getStatus());
prm_objJsonGenerator.writeNumberField("amount", prm_objObjectToSerialize.getAmount());
prm_objJsonGenerator.writeNumberField("startdate", prm_objObjectToSerialize.getStartDate().getTime());
prm_objJsonGenerator.writeNumberField("duration", prm_objObjectToSerialize.getDuration());
prm_objJsonGenerator.writeStringField("businesstype", prm_objObjectToSerialize.getBusinessType());
prm_objJsonGenerator.writeStringField("currency", prm_objObjectToSerialize.getCurrency());
prm_objJsonGenerator.writeStringField("productcategory", prm_objObjectToSerialize.getProductCategory());
prm_objJsonGenerator.writeStringField("purpose", prm_objObjectToSerialize.getPurpose());
prm_objJsonGenerator.writeStringField("mystory", prm_objObjectToSerialize.getMyStory());
prm_objJsonGenerator.writeStringField("salesRepresentative", prm_objObjectToSerialize.getSalesRepresentative());
} catch (Exception v_exException) {
//ExceptionController.getInstance().error("Error while Serializing the Loan Application Object", v_exException);
} finally {
prm_objJsonGenerator.writeEndObject();
}
}
}
}
Hope This may help u alot. Thanks..

You can do it by annotating your class with #JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)
Example:
#JsonSerialize(include=JsonSerialize.Inclusion.NON_NULL)
public myClass{
// attributes and accessors
}
You can find some useful informations at Jackson faster xml