Gson项目代码库中的RuntimeTypeAdapter据说可以很好地用于多态序列化和反序列化。我认为我尚未尝试使用它。有关更多信息，请参见http://pre.google.com/p/google-
gson/issues/detail?id=231。注意，它尚未包含在任何Gson版本中。
如果使用它不符合您的需求，则必须进行自定义反序列化处理。以下是一种这样的方法，假设您想使用演示的JSON结构。（如果JSON结构可能不同，我会采取某种不同的方法。）
import java.lang.reflect.Type;import java.util.HashMap;import java.util.List;import java.util.Map;import com.google.gson.Gson;import com.google.gson.GsonBuilder;import com.google.gson.JsonDeserializationContext;import com.google.gson.JsonDeserializer;import com.google.gson.JsonElement;import com.google.gson.JsonObject;import com.google.gson.JsonParseException;import com.google.gson.reflect.TypeToken;public class App{ public static void main(String[] args) { Barn[] barns = {new Barn(), new Barn()}; barns[0].type = "horse"; barns[0].animal = new Horse(); barns[1].type = "cow"; barns[1].animal = new Cow(); String json = new Gson().toJson(barns); // [{"type":"horse","animal":{}},{"type":"cow","animal":{}}] BarnDeserializer deserializer = new BarnDeserializer("type"); deserializer.registerBarnType("horse", Horse.class); deserializer.registerBarnType("cow", Cow.class); Gson gson = new GsonBuilder().registerTypeAdapter(Barn.class, deserializer).create(); List<Barn> barns2= gson.fromJson(json, new TypeToken<List<Barn>>(){}.getType()); for (Barn barn : barns2) { System.out.println(barn.animal.getClass()); } }}class BarnDeserializer implements JsonDeserializer<Barn>{ String barnTypeElementName; Gson gson; Map<String, Class<? extends Animal>> barnTypeRegistry; BarnDeserializer(String barnTypeElementName) { this.barnTypeElementName = barnTypeElementName; gson = new Gson(); barnTypeRegistry = new HashMap<>(); // Java 7 required for this syntax. } void registerBarnType(String barnTypeName, Class<? extends Animal> animalType) { barnTypeRegistry.put(barnTypeName, animalType); } @Override public Barn deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException { JsonObject barnObject = json.getAsJsonObject(); JsonElement animalTypeElement = barnObject.get(barnTypeElementName); Barn barn = new Barn(); barn.type = animalTypeElement.getAsString(); Class<? extends Animal> animalType = barnTypeRegistry.get(barn.type); barn.animal = gson.fromJson(barnObject.get("animal"), animalType); return barn; }}class Barn {String type; Animal animal;}class Animal {}class Horse extends Animal {}class Cow extends Animal {}
