Jackson 2.14: Serialize all fields cast to Strings

Question

In the latest Jackson 2.14 you can't use WRITE_NUMBERS_AS_STRINGS which is deprecated:

ObjectMapper mapper = new ObjectMapper();
mapper.configure(JsonGenerator.Feature.WRITE_NUMBERS_AS_STRINGS, true); // DEPRECATED!

Also you can't use @JsonSerialize(using = ToStringSerializer.class):

These were the suggestions offered in this thread. So how do we now cast fields to Strings in the latest Jackson? Some examples would be appreciated, because I couldn't find any.

score 1 · Accepted Answer · answered Mar 14 '23 at 00:44

I found the new convention. It's now called JsonWriteFeature.WRITE_NUMBERS_AS_STRING) and also .configure() needs to be put after JsonMapper.builder().

    ObjectMapper mapper = JsonMapper.builder()
                                    .configure(JsonWriteFeature.WRITE_NUMBERS_AS_STRINGS, true) 
                                    .build();

score 0 · Answer 2 · answered Mar 13 '23 at 22:21

You can try setting a method as a setter for your value. This method then converts your integer to a string.

public static void main(String[] args) throws JsonProcessingException {
    ObjectMapper mapper = new ObjectMapper();

    String json = "{\"number\": 1}";
    Model model = mapper.readValue(json, Model.class);
    System.out.println(model.getNumber());
}


public class Model {
  private String number;

  public void setNumber(@JsonProperty("number") Integer number) {
    this.number = Integer.toString(number);
  }

  public String getNumber() {
    return number;
  }
}

Jackson 2.14: Serialize all fields cast to Strings

2 Answers2