反序列化为 class 使用 Gson 扩展 LinkedHashMap

Question

我正在尝试从 JSON 反序列化为 class，它使用 Gson 扩展了 LinkedHashMap。我可以直接在 LinkedHashMap 中简单地执行此操作，但是当我尝试使用 LinkedHashMap 的 sub-class 时，出现错误

java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 3 path $.

我需要使用的类型（我没有这个，所以没有选择使用其他任何东西）：

public class ValueMap extends LinkedHashMap<CharSequence, Object> {}

我必须定义一个 InstanceCreator 来解决 CharSequence 的问题。我尝试反序列化的 JSON 作为一个基本示例是：

{"people":[{"name":"name1","surname":"name2","age":12,"dogs":["spot","fluffy","batman"],"cars":[{"name":"name1","model":1933},{"name":"name2","model":343}]},{"name":"name2","surname":"name2","age":44,"dogs":["spot","test","jack"]}]}

已更新以包含 serialization/deserialization 代码：

GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(CharSequence.class, new CharSequenceInstanceCreator());

Gson gson = gsonBuilder.create();

String serialized = gson.toJson(value);

LinkedHashMap<CharSequence, Object> deserialized = gson.fromJson(serialized, ValueMap.class);

CharSequenceInstanceCreator 看起来像：

public static class CharSequenceInstanceCreator implements InstanceCreator<CharSequence> {

    @Override
    public CharSequence createInstance(Type arg0) {
        return new String();
    }

}

Answer 1

定义 JsonDeserializer 而不是 InstanceCreator。

public static class CharSequenceDeserializer implements JsonDeserializer<CharSequence> {

    @Override
    public CharSequence deserialize(JsonElement element, Type type,
            JsonDeserializationContext context) throws JsonParseException {
        return element.getAsString();
    }

}

并注册。

//  gsonBuilder.registerTypeAdapter(CharSequence.class, new CharSequenceInstanceCreator());
gsonBuilder.registerTypeAdapter(CharSequence.class, new CharSequenceDeserializer());

反序列化为 class 使用 Gson 扩展 LinkedHashMap

Deserializing into class extending LinkedHashMap with Gson

java

linkedhashmap

gson