• JacksonFeatureCreators

Feature: Allow using Arbitrary Constructor or Factory Method for instantiation

(see Jira entry JACKSON-33 for details)

Prior to version 1.2 Jackson required use of the "default constructor" (no-arguments constructor) for instantiating all POJO/bean types, and then setting all values using "setter" methods (or starting with Jackson 1.1, direct field access).

But now it is finally possible to annotate alternative "Creator" (constructor or factory method) to use. A simple example of a Constructor-based Creator is

public class Name {
  private final String givenName, familyName;

 @JsonCreator
  public Name(@JsonProperty("givenName") String g, @JsonProperty("familyName") String f) {
    givenName = g;
    familyName = f;
  }
  public String getGivenName() { return givenName; }
  public String getFamilyName() { return familyName; }

or, with a Factory-based Creator

public class Name
{
  @JsonCreator
  public static Name createName(@JsonProperty("givenName") String g, @JsonProperty("familyName") String f) {
    // do some initialization?
    return new Name(g, f);
  }
  // ...

See Also

One feature that complements this nicely is JacksonMixInAnnotations; the main benefit being that you can use existing constructors and factory methods of third-party libraries, even if you can not modify classes themselves.

CategoryJackson