CODEWITHSUNDEEP
javajsonspring-mvcjackson
James Zalame
James Zalame

Reputation: 183

Serializing TreeModel using jackson

I have the following model:

public class CategoryModel {

    public String id;
    public String name;
    public String imageUrl;
    public CategoryModel parent;
    public List<CategoryModel> childrens = new ArrayList<CategoryModel>();
}

I am using Spring MVc + jackson to return Json.

My action build the following model and after the execution, i get stackoverflow exception.

List<CategoryModel> allCategories = new ArrayList<CategoryModel>(); 

CategoryModel model = new CategoryModel();
model.id = "1";
model.name = "category 1";

CategoryModel model1 = new CategoryModel();
model.id = "2";
model.name = "category 1.1";


model.childrens.add(model1);
model1.parent = model;

allCategories.add(model);

Any idea what's my problem ?

this is the log file (part of it):

at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:122) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:71) at org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86) at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:122) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:71) at org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86) at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:122) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:71) at org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86) at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446) at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150) at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:122) at org.codehaus.jackson.map.ser.std.StdContainerSerializers$IndexedListSerializer.serializeContents(StdContainerSerializers.java:71) Caused by: java.lang.StackOverflowError

Upvotes: 2

Views: 2979

Answers (3)

Extreme
Extreme

Reputation: 3429

keeping long story short, I have done using above suggestions as below

Summary.java
@OneToMany(cascade=CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "summary")
@JsonManagedReference
private List<Section> issueSections;

Section.java
@ManyToOne(fetch = FetchType.LAZY)
@JsonBackReference
@JoinColumn(name = "SUMMARY_ID", updatable = false)
private Summary summary;

this solved my issue.

Upvotes: 0

nutlike
nutlike

Reputation: 4975

As drorb mentioned the cyclic reference is the problem. But instead of using the @JsonIgnore annotation you should use @JsonBackReference to indicate the cyclic reference. With this annotation Jackson is able to map to the correct parent when deserializing.

Upvotes: 6

Dror Bereznitsky
Dror Bereznitsky

Reputation: 20376

You have a cyclic reference in your model between model and model1 (parent/child) which is not automatically handled by jackson. You can go around this issue by marking one of references to be ignored using the @JsonIgnore annotation. You can find more information in this article

Upvotes: 0

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