Spring and Jackson: set json ignore dynamically

Question

I have some JPA models: "Category" and "Article":

@Entity
@Table(name = "categories")
public class Category {
private int id;
private String caption;
private Category parent;
private List<Category> childrenList;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

@Column
public String getCaption() {
    return caption;
}

public void setCaption(String caption) {
    this.caption = caption;
}

@ManyToOne
@JoinColumn(name = "parent_id")
public Category getParent() {
    return parent;
}

public void setParent(Category parent) {
    this.parent = parent;
}

@OneToMany
@JoinColumn(name = "parent_id")
public List<Category> getChildrenList() {
    return childrenList;
}

public void setChildrenList(List<Category> childrenList) {
    this.childrenList = childrenList;
}
}



@Entity
@Table(name = "articles")
public class Article {
private int id;
private String caption;
private boolean isAvailable;
private String description;
private int price;
private Category category;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

@Column
public String getCaption() {
    return caption;
}

public void setCaption(String caption) {
    this.caption = caption;
}

@Column(name = "is_available")
@Type(type = "org.hibernate.type.NumericBooleanType")
public boolean getIsAvailable() {
    return isAvailable;
}

public void setIsAvailable(boolean available) {
    isAvailable = available;
}

@Column
public String getDescription() {
    return description;
}

public void setDescription(String description) {
    this.description = description;
}

@Column
public int getPrice() {
    return price;
}

public void setPrice(int price) {
    this.price = price;
}

@ManyToOne
@JoinColumn(name = "category_id")
public Category getCategory() {
    return category;
}

public void setCategory(Category category) {
    this.category = category;
}
}

Also i have some REST controller with two methods: 1)In the first method i need to get and serialize last 10 Articles, but i don't need "childrenList" and "parent" field in Categegory. 2)In the second method i need to get the same but serialize "parent" field.

How can i solve this? If i will use @JsonIgnore annotation to these fields then they will be never serialized. Or should i use DTO classes?

How can i dynamically set field for ignoring?

Welcome to Stack Overflow! I would imagine that 95% of this code is not relevant to your question. Please create a [**Minimal**, Complete and Verifiable Example](http://stackoverflow.com/help/mcve) that demonstrates your issue. — Joe C, Jan 28 '17 at 16:56

score 4 · Accepted Answer · edited May 23 '17 at 11:47

4

I never use my Entitys for generating JSON, I think another set DTO classes will make you happier in the long run. My DTO typically has a constructor which takes the Entity as argument (it still needs a default constructor if you plan to use it for parsing incoming JSON).

If you really want to use your Entities, I would recommend that you use MixIns, which allows you to register a MixIn class, that augments the serialization of a specific class.

Here is a link to a MixIn example I made for another answer.

edited May 23 '17 at 11:47

Community

1
1

answered Jan 04 '17 at 23:05

Klaus Groenbaek

4,820
2
15
30

Ok Thanks, should i create DTO class for every Entity, even if fields are equals? – Roman Roman Jan 04 '17 at 23:49

score 0 · Answer 2 · answered Jan 04 '17 at 22:02

Use a custom serializer, the psedo code is below.

public class CategorySerializer extends StdSerializer<Category> {

    public CategorySerializer() {
        this(null);
    }

    public CategorySerializer(Class<Category> t) {
        super(t);
    }

    @Override
    public void serialize(Category value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
        // put the logic here to write the parent and child value or not

        // here is the example to how the data is serialized
        jgen.writeStartObject();
        jgen.writeNumberField("id", value.id);
        jgen.writeStringField("caption", value.caption);

        jgen.writeEndObject();
    }
}

Now, to utilize the custom serializer put this annotation above your Catagory entity class.

@JsonSerialize(using = CategorySerializer.class)

If you have any conditional operation during serialization in Article class as well then you need one. Please use the custom serializer wherever needed — Avinash, Jan 04 '17 at 22:21

Spring and Jackson: set json ignore dynamically

2 Answers2