Jackson + Builder Pattern?

As long as you are using Jackson 2+, then there is now built in support for this.

First you need to add this annotation to your Address class:

@JsonDeserialize(builder = Address.Builder.class)

Then you need to add this annotation to your Builder class:

@JsonPOJOBuilder(buildMethodName = "create", withPrefix = "set")

You can skip this second annotation if you are happy to rename your Builder's create method to build, and your Builder's setters to be prefixed to with, instead of set.

Full example:

@JsonDeserialize(builder = Address.Builder.class)
public class Address
{
  private Address(Map<LocationType, String> components)
  ...

  @JsonPOJOBuilder(buildMethodName = "create", withPrefix = "set")
  public static class Builder
  {
    public Builder setCity(String value);
    public Builder setCountry(String value);
    public Address create();
  }
}

The answer from @Rupert Madden-Abbott works. However, if you have a non-default constructor, e.g.,

Builder(String city, String country) {...}

Then you should annotate the parameters as below:

@JsonCreator
Builder(@JsonProperty("city")    String city, 
        @JsonProperty("country") String country) {...}

A solution which was suitable for me in this case (I used "Lombok" builder annotation).

@Getter
@Builder(builderMethodName = "builder")
@NoArgsConstructor(access = AccessLevel.PRIVATE)
@AllArgsConstructor(access = AccessLevel.PRIVATE)
@JsonAutoDetect(
    fieldVisibility = JsonAutoDetect.Visibility.ANY,
    creatorVisibility = JsonAutoDetect.Visibility.ANY
)

I hope would be useful for u too.


I ended up implementing this using the @JsonDeserialize as follows:

@JsonDeserialize(using = JacksonDeserializer.class)
public class Address
{...}

@JsonCachable
static class JacksonDeserializer extends JsonDeserializer<Address>
{
    @Override
    public Address deserialize(JsonParser parser, DeserializationContext context)
        throws IOException, JsonProcessingException
    {
        JsonToken token = parser.getCurrentToken();
        if (token != JsonToken.START_OBJECT)
        {
            throw new JsonMappingException("Expected START_OBJECT: " + token, parser.getCurrentLocation());
        }
        token = parser.nextToken();
        Builder result = new Builder();
        while (token != JsonToken.END_OBJECT)
        {
            if (token != JsonToken.FIELD_NAME)
            {
                throw new JsonMappingException("Expected FIELD_NAME: " + token, parser.getCurrentLocation());
            }
            LocationType key = LocationType.valueOf(parser.getText());

            token = parser.nextToken();
            if (token != JsonToken.VALUE_STRING)
            {
                throw new JsonMappingException("Expected VALUE_STRING: " + token, parser.getCurrentLocation());
            }
            String value = parser.getText();

            // Our Builder allows passing key-value pairs
            // alongside the normal setter methods.
            result.put(key, value);
            token = parser.nextToken();
        }
        return result.create();
    }
}