Large json files are available (from 100 MB to 2 GB).
How I can create java (pojo) from json? I need to get the names of all fields. For example, one class can have more than 1000 fields.
Tried the following libraries & online services:
JsonSchema2Pojo works well, but has a limit of about 50,000 characters at a time. Due to the presence of limits, I cannot completely map the class. Need to partially copy the json each time and then remove the duplicate fields.
http://www.jsonschema2pojo.org/
JsonToJava
https://github.com/astav/JsonToJava
Also tried several other online services. They also have limits or do not work correctly.
Example of json file:
{"type":"FeatureCollection","features":[
{"type":"Feature","geometry":{"type":"Point","coordinates":[27.5618791,53.902334]},"properties":{"ele":"280","name":"Минск","place":"city","capital":"yes","name:ar":"مينسك","name:be":"Мінск","name:bg":"Минск","name:bo":"མིན་སིཀ།","name:cs":"Minsk","name:cu":"Мѣньскъ","name:cv":"Минск","name:de":"Minsk","name:el":"Μινσκ","name:en":"Minsk","name:eo":"Minsko","name:es":"Minsk","name:et":"Minsk","name:fa":"مینسک","name:fi":"Minsk","name:fr":"Minsk","name:ga":"Minsc","name:gl":"Minsk - Мінск","name:he":"מינסק","name:hi":"मिन्स्क","name:hr":"Minsk","name:hu":"Minszk","name:hy":"Մինսկ","name:ia":"Minsk","name:io":"Minsk","name:is":"Minsk","name:it":"Minsk","name:ja":"ミンスク","name:ka":"მინსკი","name:kk":"Минск","name:kn":"ಮಿನ್ಸ್ಕ್","name:ko":"민스크","name:ku":"Mînsk","name:kv":"Минск","name:ky":"Минск","name:la":"Minscum","name:lt":"Minskas","name:lv":"Minska","name:mk":"Минск","name:ml":"മിൻസ്ക്","name:mr":"मिन्स्क","name:nl":"Minsk","name:no":"Minsk","name:oc":"Minsk","name:os":"Минск","name:pl":"Mińsk","name:pt":"Minsk","name:ru":"Минск","name:sk":"Minsk","name:sl":"Minsk","name:sr":"Минск","name:sv":"Minsk","name:ta":"மின்ஸ்க்","name:tg":"Минск","name:th":"มินสก์","name:tt":"Минск","name:ug":"مىنىسكى","name:uk":"Мінськ","name:ur":"منسک","name:vi":"Minxcơ","name:vo":"Minsk","name:yi":"מינסק","name:zh":"明斯克","website":"https://minsk.gov.by/","int_name":"Minsk","name:ast":"Minsk","name:ckb":"مینسک","name:csb":"Mińsk","name:jbo":"misk","name:mhr":"Минск","name:myv":"Минск ош","name:nds":"Minsk","name:pnb":"منسک","name:rue":"Мінск","name:sah":"Минскай","name:szl":"Mińsk","name:udm":"Минск","name:wuu":"明斯克","nat_name":"Мінск","old_name":"Менск","wikidata":"Q2280","wikipedia":"ru:Минск","population":"1982444","admin_level":"2","alt_name:be":"Менск","alt_name:vi":"Minsk;Minxcơva","name:prefix":"город","old_name:be":"Менск","addr:country":"BY","name:bat-smg":"Minsks","name:sr-Latn":"Minsk","wikipedia:be":"Мінск","wikipedia:en":"Minsk","wikipedia:pl":"Mińsk","addr:postcode":"220000","is_in:country":"Belarus","name:be-tarask":"Менск","source:name:oc":"Lo Congrès","is_in:continent":"Europe","population:date":"2018-01-01","capital_ISO3166-1":"yes","source:population":"Белстат","is_in:country_code":"BY"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5861178,53.9510657],[27.5861196,53.9510294],[27.5862319,53.9510313],[27.5862302,53.9510676],[27.5861178,53.9510657]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5885075,53.9512721],[27.5885398,53.9511614],[27.5887363,53.9511813],[27.588704,53.9512919],[27.5885075,53.9512721]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5881428,53.9512622],[27.5881704,53.9511135],[27.588421,53.9511296],[27.5883935,53.9512783],[27.5881428,53.9512622]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5892179,53.9516538],[27.5893274,53.9516011],[27.5893778,53.9516374],[27.5894352,53.9516098],[27.5895358,53.9516823],[27.5893689,53.9517626],[27.5892179,53.9516538]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.588949,53.9517486],[27.5891273,53.9516621],[27.5892764,53.9517686],[27.5890981,53.9518551],[27.588949,53.9517486]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5867595,53.9500825],[27.5867648,53.9499951],[27.5869291,53.9499985],[27.5869238,53.9500859],[27.5867595,53.9500825]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5830382,53.9503042],[27.5830422,53.9502013],[27.5832783,53.9502045],[27.5832743,53.9503074],[27.5830382,53.9503042]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5820906,53.9497446],[27.5820973,53.9496721],[27.5822371,53.9496765],[27.5822305,53.949749],[27.5820906,53.9497446]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5477403,53.8940388],[27.5482144,53.8939744],[27.5482459,53.8940791],[27.5482929,53.8940736],[27.5483083,53.8941424],[27.5482593,53.8941471],[27.5482741,53.8942048],[27.5485718,53.8943067],[27.5487113,53.8943028],[27.5487556,53.8943755],[27.548895,53.8944261],[27.5487985,53.894513],[27.5488079,53.8945841],[27.5483385,53.8943889],[27.548317,53.8943202],[27.5481439,53.8942549],[27.5481045,53.8941843],[27.5479863,53.8942063],[27.5479953,53.8942214],[27.5478248,53.8942506],[27.5477403,53.8940388]]]]},"properties":{"name":"Инженерный корпус метрополитена","building":"yes"}}
]}
Thanks in advance!
Thanks a lot for your advices.
Implemented in the following way:
I used JsonAnySetter annotation to set all fields instead creating pojo with all of the possible fields.
Here is my Dto's
FeatureDto
#Getter
#ToString
public class FeatureDto {
#JsonProperty("type")
private String type;
#JsonProperty("geometry")
private GeometryDto geometry;
#JsonProperty("properties")
private PropertiesDto properties;
}
PropertiesDto
#Getter
#ToString
public class PropertiesDto {
private List<FieldDto> fieldDtos = new ArrayList<>();
#JsonAnySetter
public void setProperties(String code, Object value)
{
if(value instanceof ArrayList) {
ArrayList<Object> list = (ArrayList<Object>) value;
StringBuffer stringBuffer = new StringBuffer();
list.forEach(o -> stringBuffer.append(o).append(", "));
fieldDtos.add(new FieldDto(code, stringBuffer.toString()));
return;
}
fieldDtos.add(new FieldDto(code, value.toString()));
}
}
FieldDto
#Data
#ToString
#JsonIgnoreProperties(ignoreUnknown = true)
#AllArgsConstructor
public class FieldDto {
#JsonProperty("code")
private String code;
#JsonProperty("value")
private String value;
}
Here is the json source:
{"type":"FeatureCollection","features":[
{"type":"Feature","geometry":{"type":"Point","coordinates":[27.5618791,53.902334]},"properties":{"ele":"280","name":"Минск","place":"city","capital":"yes","name:ar":"مينسك","name:be":"Мінск","name:bg":"Минск","name:bo":"མིན་སིཀ།","name:cs":"Minsk","name:cu":"Мѣньскъ","name:cv":"Минск","name:de":"Minsk","name:el":"Μινσκ","name:en":"Minsk","name:eo":"Minsko","name:es":"Minsk","name:et":"Minsk","name:fa":"مینسک","name:fi":"Minsk","name:fr":"Minsk","name:ga":"Minsc","name:gl":"Minsk - Мінск","name:he":"מינסק","name:hi":"मिन्स्क","name:hr":"Minsk","name:hu":"Minszk","name:hy":"Մինսկ","name:ia":"Minsk","name:io":"Minsk","name:is":"Minsk","name:it":"Minsk","name:ja":"ミンスク","name:ka":"მინსკი","name:kk":"Минск","name:kn":"ಮಿನ್ಸ್ಕ್","name:ko":"민스크","name:ku":"Mînsk","name:kv":"Минск","name:ky":"Минск","name:la":"Minscum","name:lt":"Minskas","name:lv":"Minska","name:mk":"Минск","name:ml":"മിൻസ്ക്","name:mr":"मिन्स्क","name:nl":"Minsk","name:no":"Minsk","name:oc":"Minsk","name:os":"Минск","name:pl":"Mińsk","name:pt":"Minsk","name:ru":"Минск","name:sk":"Minsk","name:sl":"Minsk","name:sr":"Минск","name:sv":"Minsk","name:ta":"மின்ஸ்க்","name:tg":"Минск","name:th":"มินสก์","name:tt":"Минск","name:ug":"مىنىسكى","name:uk":"Мінськ","name:ur":"منسک","name:vi":"Minxcơ","name:vo":"Minsk","name:yi":"מינסק","name:zh":"明斯克","website":"https://minsk.gov.by/","int_name":"Minsk","name:ast":"Minsk","name:ckb":"مینسک","name:csb":"Mińsk","name:jbo":"misk","name:mhr":"Минск","name:myv":"Минск ош","name:nds":"Minsk","name:pnb":"منسک","name:rue":"Мінск","name:sah":"Минскай","name:szl":"Mińsk","name:udm":"Минск","name:wuu":"明斯克","nat_name":"Мінск","old_name":"Менск","wikidata":"Q2280","wikipedia":"ru:Минск","population":"1982444","admin_level":"2","alt_name:be":"Менск","alt_name:vi":"Minsk;Minxcơva","name:prefix":"город","old_name:be":"Менск","addr:country":"BY","name:bat-smg":"Minsks","name:sr-Latn":"Minsk","wikipedia:be":"Мінск","wikipedia:en":"Minsk","wikipedia:pl":"Mińsk","addr:postcode":"220000","is_in:country":"Belarus","name:be-tarask":"Менск","source:name:oc":"Lo Congrès","is_in:continent":"Europe","population:date":"2018-01-01","capital_ISO3166-1":"yes","source:population":"Белстат","is_in:country_code":"BY"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5861178,53.9510657],[27.5861196,53.9510294],[27.5862319,53.9510313],[27.5862302,53.9510676],[27.5861178,53.9510657]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5885075,53.9512721],[27.5885398,53.9511614],[27.5887363,53.9511813],[27.588704,53.9512919],[27.5885075,53.9512721]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5881428,53.9512622],[27.5881704,53.9511135],[27.588421,53.9511296],[27.5883935,53.9512783],[27.5881428,53.9512622]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5892179,53.9516538],[27.5893274,53.9516011],[27.5893778,53.9516374],[27.5894352,53.9516098],[27.5895358,53.9516823],[27.5893689,53.9517626],[27.5892179,53.9516538]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.588949,53.9517486],[27.5891273,53.9516621],[27.5892764,53.9517686],[27.5890981,53.9518551],[27.588949,53.9517486]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5867595,53.9500825],[27.5867648,53.9499951],[27.5869291,53.9499985],[27.5869238,53.9500859],[27.5867595,53.9500825]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5830382,53.9503042],[27.5830422,53.9502013],[27.5832783,53.9502045],[27.5832743,53.9503074],[27.5830382,53.9503042]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5820906,53.9497446],[27.5820973,53.9496721],[27.5822371,53.9496765],[27.5822305,53.949749],[27.5820906,53.9497446]]]]},"properties":{"building":"yes"}},
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[27.5477403,53.8940388],[27.5482144,53.8939744],[27.5482459,53.8940791],[27.5482929,53.8940736],[27.5483083,53.8941424],[27.5482593,53.8941471],[27.5482741,53.8942048],[27.5485718,53.8943067],[27.5487113,53.8943028],[27.5487556,53.8943755],[27.548895,53.8944261],[27.5487985,53.894513],[27.5488079,53.8945841],[27.5483385,53.8943889],[27.548317,53.8943202],[27.5481439,53.8942549],[27.5481045,53.8941843],[27.5479863,53.8942063],[27.5479953,53.8942214],[27.5478248,53.8942506],[27.5477403,53.8940388]]]]},"properties":{"name":"Инженерный корпус метрополитена","building":"yes"}}
]}
I am writing a serializer to serialize POJO to JSON but stuck in circular reference problem. In hibernate bidirectional one-to-many relation, parent references child and child references back to parent and here my serializer dies. (see example code below)
How to break this cycle? Can we get owner tree of an object to see whether object itself exists somewhere in its own owner hierarchy? Any other way to find if the reference is going to be circular? or any other idea to resolve this problem?
I rely on Google JSON To handle this kind of issue by using The feature
Excluding Fields From Serialization and Deserialization
Suppose a bi-directional relationship between A and B class as follows
public class A implements Serializable {
private B b;
}
And B
public class B implements Serializable {
private A a;
}
Now use GsonBuilder To get a custom Gson object as follows (Notice setExclusionStrategies method)
Gson gson = new GsonBuilder()
.setExclusionStrategies(new ExclusionStrategy() {
public boolean shouldSkipClass(Class<?> clazz) {
return (clazz == B.class);
}
/**
* Custom field exclusion goes here
*/
public boolean shouldSkipField(FieldAttributes f) {
return false;
}
})
/**
* Use serializeNulls method if you want To serialize null values
* By default, Gson does not serialize null values
*/
.serializeNulls()
.create();
Now our circular reference
A a = new A();
B b = new B();
a.setB(b);
b.setA(a);
String json = gson.toJson(a);
System.out.println(json);
Take a look at GsonBuilder class
Jackson 1.6 (released september 2010) has specific annotation-based support for handling such parent/child linkage, see http://wiki.fasterxml.com/JacksonFeatureBiDirReferences. (Wayback Snapshot)
You can of course already exclude serialization of parent link already using most JSON processing packages (jackson, gson and flex-json at least support it), but the real trick is in how to deserialize it back (re-create parent link), not just handle serialization side. Although sounds like for now just exclusion might work for you.
EDIT (April 2012): Jackson 2.0 now supports true identity references (Wayback Snapshot), so you can solve it this way also.
Can a bi-directional relationship even be represented in JSON? Some data formats are not good fits for some types of data modelling.
One method for dealing with cycles when dealing with traversing object graphs is to keep track of which objects you've seen so far (using identity comparisons), to prevent yourself from traversing down an infinite cycle.
In addressing this problem, I took the following approach (standardizing the process across my application, making the code clear and reusable):
Create an annotation class to be used on fields you'd like excluded
Define a class which implements Google's ExclusionStrategy interface
Create a simple method to generate the GSON object using the GsonBuilder (similar to Arthur's explanation)
Annotate the fields to be excluded as needed
Apply the serialization rules to your com.google.gson.Gson object
Serialize your object
Here's the code:
1)
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
#Retention(RetentionPolicy.RUNTIME)
#Target({ElementType.FIELD, ElementType.METHOD})
public #interface GsonExclude {
}
2)
import com.google.gson.ExclusionStrategy;
import com.google.gson.FieldAttributes;
public class GsonExclusionStrategy implements ExclusionStrategy{
private final Class<?> typeToExclude;
public GsonExclusionStrategy(Class<?> clazz){
this.typeToExclude = clazz;
}
#Override
public boolean shouldSkipClass(Class<?> clazz) {
return ( this.typeToExclude != null && this.typeToExclude == clazz )
|| clazz.getAnnotation(GsonExclude.class) != null;
}
#Override
public boolean shouldSkipField(FieldAttributes f) {
return f.getAnnotation(GsonExclude.class) != null;
}
}
3)
static Gson createGsonFromBuilder( ExclusionStrategy exs ){
GsonBuilder gsonbuilder = new GsonBuilder();
gsonbuilder.setExclusionStrategies(exs);
return gsonbuilder.serializeNulls().create();
}
4)
public class MyObjectToBeSerialized implements Serializable{
private static final long serialVersionID = 123L;
Integer serializeThis;
String serializeThisToo;
Date optionalSerialize;
#GsonExclude
#ManyToOne(fetch=FetchType.LAZY, optional=false)
#JoinColumn(name="refobj_id", insertable=false, updatable=false, nullable=false)
private MyObjectThatGetsCircular dontSerializeMe;
...GETTERS AND SETTERS...
}
5)
In the first case, null is supplied to the constructor, you can specify another class to be excluded - both options are added below
Gson gsonObj = createGsonFromBuilder( new GsonExclusionStrategy(null) );
Gson _gsonObj = createGsonFromBuilder( new GsonExclusionStrategy(Date.class) );
6)
MyObjectToBeSerialized _myobject = someMethodThatGetsMyObject();
String jsonRepresentation = gsonObj.toJson(_myobject);
or, to exclude the Date object
String jsonRepresentation = _gsonObj.toJson(_myobject);
If you are using Jackon to serialize, just apply #JsonBackReference to your bi-directinal mapping
It will solve the circular reference problem.
Note : #JsonBackReference is used to solve the Infinite recursion (StackOverflowError)
Used a solution similar to Arthur's but instead of setExclusionStrategies I used
Gson gson = new GsonBuilder()
.excludeFieldsWithoutExposeAnnotation()
.create();
and used #Expose gson annotation for fields which I need in the json, other fields are excluded.
if you are using spring boot,Jackson throws error while creating response from circular/bidirectional data, so use
#JsonIgnoreProperties
to ignore circularity
At Parent:
#OneToMany(mappedBy="dbApp")
#JsonIgnoreProperties("dbApp")
private Set<DBQuery> queries;
At child:
#ManyToOne
#JoinColumn(name = "db_app_id")
#JsonIgnoreProperties("queries")
private DBApp dbApp;
If you are using Javascript, there's a very easy solution to that using the replacer parameter of JSON.stringify() method where you can pass a function to modify the default serialization behavior.
Here's how you can use it. Consider the below example with 4 nodes in a cyclic graph.
// node constructor
function Node(key, value) {
this.name = key;
this.value = value;
this.next = null;
}
//create some nodes
var n1 = new Node("A", 1);
var n2 = new Node("B", 2);
var n3 = new Node("C", 3);
var n4 = new Node("D", 4);
// setup some cyclic references
n1.next = n2;
n2.next = n3;
n3.next = n4;
n4.next = n1;
function normalStringify(jsonObject) {
// this will generate an error when trying to serialize
// an object with cyclic references
console.log(JSON.stringify(jsonObject));
}
function cyclicStringify(jsonObject) {
// this will successfully serialize objects with cyclic
// references by supplying #name for an object already
// serialized instead of passing the actual object again,
// thus breaking the vicious circle :)
var alreadyVisited = [];
var serializedData = JSON.stringify(jsonObject, function(key, value) {
if (typeof value == "object") {
if (alreadyVisited.indexOf(value.name) >= 0) {
// do something other that putting the reference, like
// putting some name that you can use to build the
// reference again later, for eg.
return "#" + value.name;
}
alreadyVisited.push(value.name);
}
return value;
});
console.log(serializedData);
}
Later, you can easily recreate the actual object with the cyclic references by parsing the serialized data and modifying the next property to point to the actual object if it's using a named reference with a # like in this example.
This is how i finally solved it in my case. This works at least with Gson & Jackson.
private static final Gson gson = buildGson();
private static Gson buildGson() {
return new GsonBuilder().addSerializationExclusionStrategy( getExclusionStrategy() ).create();
}
private static ExclusionStrategy getExclusionStrategy() {
ExclusionStrategy exlStrategy = new ExclusionStrategy() {
#Override
public boolean shouldSkipField(FieldAttributes fas) {
return ( null != fas.getAnnotation(ManyToOne.class) );
}
#Override
public boolean shouldSkipClass(Class<?> classO) {
return ( null != classO.getAnnotation(ManyToOne.class) );
}
};
return exlStrategy;
}
Jackson provides JsonIdentityInfo annotation to prevent circular references. You can check the tutorial here.
This error can appened when you have two objects :
class object1{
private object2 o2;
}
class object2{
private object1 o1;
}
With using GSon for serialization, i have got this error :
java.lang.IllegalStateException: circular reference error
Offending field: o1
To solved this, just add key word transient :
class object1{
private object2 o2;
}
class object2{
transient private object1 o1;
}
As you can see here : Why does Java have transient fields?
The transient keyword in Java is used to indicate that a field should not be serialized.
If you use GSON to convert Java class in JSON you can avoid the fields that cause the circular reference and the infinitive loop, you only have to put the annotation #Expose in the fields that you want to appear in the JSON, and the fields without the annotation #Expose do not appear in the JSON.
The circular reference appears for example if we try to serialize the class User with the field routes of class Route, and the class Route have the field user of the class User, then GSON try to serialize the class User and when try to serialize routes, serialize the class Route and in the class Route try to serialize the field user, and again try to serialize the class User, there is a circular reference that provoke the infinitive loop. I show the class User and Route that mentioned.
import com.google.gson.annotations.Expose;
Class User
#Entity
#Table(name = "user")
public class User {
#Column(name = "name", nullable = false)
#Expose
private String name;
#OneToMany(mappedBy = "user", fetch = FetchType.EAGER)
#OnDelete(action = OnDeleteAction.CASCADE)
private Set<Route> routes;
#ManyToMany(fetch = FetchType.EAGER)
#OnDelete(action = OnDeleteAction.CASCADE)
#JoinTable(name = "like_", joinColumns = #JoinColumn(name = "id_user"),
inverseJoinColumns = #JoinColumn(name = "id_route"),
foreignKey = #ForeignKey(name = ""),
inverseForeignKey = #ForeignKey(name = ""))
private Set<Route> likes;
Class Route
#Entity
#Table(name = "route")
public class Route {
#ManyToOne()
#JoinColumn(nullable = false, name = "id_user", foreignKey =
#ForeignKey(name = "c"))
private User user;
To avoid the infinitive loop, we use the annotation #Expose that offer GSON.
I show in format JSON the result of serialize with GSON the class User.
{
"name": "ignacio"
}
We can see that the field route and likes do not exist in the format JSON, only the field name. Because of this, the circular reference is avoid.
If we want to use that, we have to create an object GSON on a specific way.
Gson converterJavaToJson = new GsonBuilder().setPrettyPrinting().excludeFieldsWithoutExposeAnnotation().create();
In the end, we transform the java class of the model of hibernate user using the conversor GSON created.
User user = createUserWithHibernate();
String json = converterJavaToJson.toJson(user);
the answer number 8 is the better, i think so if you know what field is throwing a error the you only set the fild in null and solved.
List<RequestMessage> requestMessages = lazyLoadPaginated(first, pageSize, sortField, sortOrder, filters, joinWith);
for (RequestMessage requestMessage : requestMessages) {
Hibernate.initialize(requestMessage.getService());
Hibernate.initialize(requestMessage.getService().getGroupService());
Hibernate.initialize(requestMessage.getRequestMessageProfessionals());
for (RequestMessageProfessional rmp : requestMessage.getRequestMessageProfessionals()) {
Hibernate.initialize(rmp.getProfessional());
rmp.setRequestMessage(null); // **
}
}
To make the code readable a big comment is moved from the comment // ** to below.
java.lang.StackOverflowError [Request processing failed; nested exception is org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Infinite recursion (StackOverflowError) (through reference chain: com.service.pegazo.bo.RequestMessageProfessional["requestMessage"]->com.service.pegazo.bo.RequestMessage["requestMessageProfessionals"]
For example, ProductBean has got serialBean. The mapping would be bi-directional relationship. If we now try to use gson.toJson(), it will end up with circular reference. In order to avoid that problem, you can follow these steps:
Retrieve the results from datasource.
Iterate the list and make sure the serialBean is not null, and then
Set productBean.serialBean.productBean = null;
Then try to use gson.toJson();
That should solve the problem