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?

Answer 1

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.