How to use Jackson's TypeReference with generics?

TypeReference requires you to specify parameters statically, not dynamically, so it does not work if you need to further parameterize types.

What I think you need is JavaType: you can build instances dynamically by using TypeFactory. You get an instance of TypeFactory via ObjectMapper.getTypeFactory(). You can also construct JavaType instances from simple Class as well as TypeReference.

One approach will be to define a Jackson JavaType representing a list of items of type clazz. You still need to have access to the class of the generic parameter at runtime. The usual approach is something like

<T> class XX { XX(Class<T> clazz, ...) ... } 

to pass the class of the generic parameter into the generic class at construction.

Upon access to the Class clazz variable you can construct a Jackson JavaType representing, for example, a list of items of class clazz with the following statement.

JavaType itemType = mapper.getTypeFactory().constructCollectionType(List.class, clazz);

I hope it helped. I am using this approach in my own code.

Try this:

    import com.fasterxml.jackson.databind.ObjectMapper;    import java.lang.reflect.Array;    import java.util.Arrays;        ...            public static <TargetType> List<TargetType> convertToList(String jsonString, Class<TargetType> targetTypeClass) {        List<TargetType> listOfTargetObjects = null;        ObjectMapper objectMapper = new ObjectMapper();        TargetType[] arrayOfTargetType = (TargetType[]) Array.newInstance(targetTypeClass, 0);        try {            listOfTargetObjects = (List<TargetType>) Arrays.asList(objectMapper.readValue(jsonString, arrayOfTargetType.getClass()));        } catch (JsonMappingException jsonMappingException) {            listOfTargetObjects = null;        } catch (JsonProcessingException jsonProcessingException) {            listOfTargetObjects = null;        } catch (Exception exception) {            listOfTargetObjects = null;        }        return listOfTargetObjects;    }...