How to use Jackson to deserialize an array of objects

Question

The Jackson data binding documentation indicates that Jackson supports deserialising "Arrays of all supported types" but I can't figure out the exact syntax for this.

For a single object I would do this:

//json input { "id" : "junk", "stuff" : "things" } //Java MyClass instance = objectMapper.readValue(json, MyClass.class);

Now for an array I want to do this:

//json input [{ "id" : "junk", "stuff" : "things" }, { "id" : "spam", "stuff" : "eggs" }] //Java List<MyClass> entries = ?

Anyone know if there is a magic missing command? If not then what is the solution?

Answer 1

You need to create a mapper first:

import com.fasterxml.jackson.databind.ObjectMapper;// in play 2.3

ObjectMapper mapper = new ObjectMapper();

 

To specify as List use:

List<MyClass> myObjects = mapper.readValue(jsonInput, new TypeReference<List<MyClass>>(){});

or

List<MyClass> myObjects = mapper.readValue(jsonInput, mapper.getTypeFactory().constructCollectionType(List.class, MyClass.class));

 

To specify as Array use:

MyClass[] myObjects = mapper.readValue(json, MyClass[].class);