Deserialize JSON to ArrayList<POJO> using Jackson

You can deserialize directly to a list by using the TypeReference wrapper. An example method:

public static <T> T fromJSON(final TypeReference<T> type,
      final String jsonPacket) {
   T data = null;

   try {
      data = new ObjectMapper().readValue(jsonPacket, type);
   } catch (Exception e) {
      // Handle the problem
   }
   return data;
}

And is used thus:

final String json = "";
Set<POJO> properties = fromJSON(new TypeReference<Set<POJO>>() {}, json);

TypeReference Javadoc


Another way is to use an array as a type, e.g.:

ObjectMapper objectMapper = new ObjectMapper();
MyPojo[] pojos = objectMapper.readValue(json, MyPojo[].class);

This way you avoid all the hassle with the Type object, and if you really need a list you can always convert the array to a list by:

List<MyPojo> pojoList = Arrays.asList(pojos);

IMHO this is much more readable.

And to make it be an actual list (that can be modified, see limitations of Arrays.asList()) then just do the following:

List<MyPojo> mcList = new ArrayList<>(Arrays.asList(pojos));

This variant looks more simple and elegant.

CollectionType typeReference =
    TypeFactory.defaultInstance().constructCollectionType(List.class, Dto.class);
List<Dto> resultDto = objectMapper.readValue(content, typeReference);