Gson处理对象或数组

Question

我有以下课程public class MyClass {    private List<MyOtherClass> others;}public class MyOtherClass {    private String name;}我有可能看起来像这样的JSON{  others: {    name: "val"  }}或这个{  others: [    {      name: "val"    },    {      name: "val"    }  ]}我希望能够MyClass对这两种JSON格式使用相同的格式。有办法用Gson做到这一点吗？

Answer 1

谢谢您提供的三个杯子！

如果需要多个类型，则与泛型类型相同：

public class SingleElementToListDeserializer<T> implements JsonDeserializer<List<T>> {

private final Class<T> clazz;

public SingleElementToListDeserializer(Class<T> clazz) {

    this.clazz = clazz;

}

public List<T> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {

    List<T> resultList = new ArrayList<>();

    if (json.isJsonArray()) {

        for (JsonElement e : json.getAsJsonArray()) {

            resultList.add(context.<T>deserialize(e, clazz));

        }

    } else if (json.isJsonObject()) {

        resultList.add(context.<T>deserialize(json, clazz));

    } else {

        throw new RuntimeException("Unexpected JSON type: " + json.getClass());

    }

    return resultList;

    }

}

并配置Gson：

Type myOtherClassListType = new TypeToken<List<MyOtherClass>>() {}.getType();

SingleElementToListDeserializer<MyOtherClass> adapter = new SingleElementToListDeserializer<>(MyOtherClass.class);

Gson gson = new GsonBuilder()

    .registerTypeAdapter(myOtherClassListType, adapter)

    .create();

Answer 2

建立三杯的答案，我有以下让JsonArray直接反序列化为数组的方法。

static public <T> T[] fromJsonAsArray(Gson gson, JsonElement json, Class<T> tClass, Class<T[]> tArrClass)

        throws JsonParseException {

    T[] arr;

    if(json.isJsonObject()){

        //noinspection unchecked

        arr = (T[]) Array.newInstance(tClass, 1);

        arr[0] = gson.fromJson(json, tClass);

    }else if(json.isJsonArray()){

        arr = gson.fromJson(json, tArrClass);

    }else{

        throw new RuntimeException("Unexpected JSON type: " + json.getClass());

    }

    return arr;

}

用法：

    String response = ".......";

    JsonParser p = new JsonParser();

    JsonElement json = p.parse(response);

    Gson gson = new Gson();

    MyQuote[] quotes = GsonUtils.fromJsonAsArray(gson, json, MyQuote.class, MyQuote[].class);