Java如何为Gson编写自定义JSON解串器？

@Overridepublic User deserialize(JsonElement json, Type type,        JsonDeserializationContext context) throws JsonParseException {    JsonObject jobject = json.getAsJsonObject();    return new User( jobject.get("id").getAsInt(),  jobject.get("name").getAsString(),  new Timestamp(jobject.get("update_date").getAsLong()));}