如何将JSON读取到java中的通用对象列表？

Question

I have to get data from a web service, I'm using Jackson but I have the same problem using Gson, I have no problem with single objects but when I receive several objects list it is not that easy for me.

JSON received are like this:

{"country":
[
{"code":"AD","nombre":"Andorra","name":"Andorra"},
{"code":"AE","nombre":"Emiratos Árabes Unidos","name":"United Arab Emirates"}
]
}

This is a list of my own class CountryWSType , I have several classes like this and need a way that can get the list of any type of them. I've tried parse it like a list:

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

Also trying creating an own list type:

    public class ListWSType<T> implements List<T>{

    private List<T> listaInterna;

    //implents methods
    }

But I always get a JsonMappingException and I have no more ideas of how to do it.

I hope someone can help me.

As some people ask here is the class i was trying to parse from a JSON:

@XmlRootElement(name="country")
@XmlType(propOrder={"code", "nombre", "name"})
public class CountryWSType {

    /** Código ISO */
    @XmlElement(name="code")
    public String code;

    /** Nombre en español */
    @XmlElement(name="nombre")
    public String nombre;

    /** Nombre en inglés */
    @XmlElement(name="name")
    public String name;

    /** Constructor sin parámetros. No inicializa nada...
     * Está para que funcione el marshall/unmarshall.
     */
    public CountryWSType() {}
}

Also notice than when i put MyClass it means CountryWSType class, sorry for the missunderstood.

Answer 1

May be this will help:

//first convert input string to json array
JSONObject jsonobject = new JSONObject(countriesAsJsonString);

JSONArray jsonArray = jsnobject.getJSONArray("countries");

//then get the type for list and parse using gson as
Type listType = new TypeToken<List<MyClass>>(){}.getType();
List<MyClass> countriesList = new Gson().fromJson(jsonArray, listType);

If you are saying your json arrary elements can be of different types, than the mapper will not know which type of class to instantiate and you will need to supply additional attribute in your json to indicate that, an ugly approach specially if the json is external facing. But if this is what you want than it is explained in this SO post.