Deserializing JSON into object with overloaded methods using Jackson

Question

I am attempting to deserialize a JSON object stored in CouchDb using Jackson. This object needs to deserialize into a pojo that contains overloaded methods. When I attempt

Answer 1

It's not necessary to change the name of the setter method to avoid ambiguity. You're otherwise on the right track with @JsonIgnore. With @JsonIgnore on all of the same-named methods to be ignored, the one to use does not need the @JsonProperty annotation.

Here's a simple example to demonstrate this point.

input.json: {"value":"forty-two"}

Foo.java:

import java.io.File;

import org.codehaus.jackson.annotate.JsonIgnore;
import org.codehaus.jackson.map.ObjectMapper;

public class Foo
{
  String value;

  public String getValue() {return value;}
  public void setValue(String value) {this.value = value;}

  @JsonIgnore
  public void setValue(int value) {this.value = String.valueOf(value);}

  public static void main(String[] args) throws Exception
  {
    ObjectMapper mapper = new ObjectMapper();
    Foo foo = mapper.readValue(new File("input.json"), Foo.class);
    System.out.println(mapper.writeValueAsString(foo));
  }
}

If you don't want to alter the pristine POJO defs with a Jackson annotation, then you can use a MixIn.

import java.io.File;

import org.codehaus.jackson.annotate.JsonIgnore;
import org.codehaus.jackson.map.ObjectMapper;

public class Foo
{
  String value;

  public String getValue() {return value;}
  public void setValue(String value) {this.value = value;}
  public void setValue(int value) {this.value = String.valueOf(value);}

  public static void main(String[] args) throws Exception
  {
    ObjectMapper mapper = new ObjectMapper();
    mapper.getDeserializationConfig().addMixInAnnotations(Foo.class, IgnoreFooSetValueIntMixIn.class);
    Foo foo = mapper.readValue(new File("input.json"), Foo.class);
    System.out.println(mapper.writeValueAsString(foo));
  }
}

abstract class IgnoreFooSetValueIntMixIn
{
  @JsonIgnore public abstract void setValue(int value);
}

Answer 2

In cases where @JsonIgnore doesn't help (I currently have such a case, but am still unsure of the reason), it is also possible to use @XmlTransient instead.

Answer 3

In Jackson > 2.4 use directly :

mapper.addMixIn(Foo.class, IgnoreFooSetValueIntMixIn.class);