Make Jackson interpret single JSON object as array with one element

Question

Is there a way to make Jackson interpret single JSON object as an array with one element and vice versa?

Example, I have 2 slightly different formats of JSON, I need both to map to same Java object:

Format A (JSON array with one element):

points : [ {     date : 2013-05-11     value : 123 }] 

Format B (JSON object, yes I know it looks "wrong" but it's what I'm given):

points : {     date : 2013-05-11     value : 123 } 

Target Java object that both of the above should convert to:

//Data.java  public List<Point> points; //other members omitted  //Point.java class Point {     public String date;     public int value; } 

Currently, only A will parse properly to Data. I want avoid directly tampering with the JSON itself. Is there some configuration in Jackson I can tamper with in order to make it accept B ?

Answer 1

Try with DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY - it should work for you.

Example:

final String json = "{\"date\" : \"2013-05-11\",\"value\" : 123}";  final ObjectMapper mapper = new ObjectMapper()         .enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY); final List<Point> points = mapper.readValue(json,         new TypeReference<List<Point>>() {}); 

Answer 2

The Jackson 1.x-compatible version uses DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY. So the above answer changes to:

final String json = "{\"date\" : \"2013-05-11\",\"value\" : 123}";  final ObjectMapper mapper = new ObjectMapper()     .enable(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY); final List<Point> points = mapper.readValue(json,     new TypeReference<List<Point>>() {     }); System.out.println(points);