【转】Json转换利器Gson之实例五注册TypeAdapter及处理Enum类型

public enum PackageState {PLAY, UPDATE, UPDATING, DOWNLOAD, DOWNLOADING,
}


public class PackageItem {private String name;private PackageState state;private String size;public String getName() {return name;}public void setName(String name) {this.name &＃61; name;}public PackageState getState() {return state;}public void setState(PackageState state) {this.state &＃61; state;}public String getSize() {return size;}public void setSize(String size) {this.size &＃61; size;}&＃64;Overridepublic String toString() {return "PackageItem [name&＃61;" &＃43; name &＃43; ", size&＃61;" &＃43; size &＃43; ", state&＃61;"&＃43; state &＃43; "]";}
}


mport java.lang.reflect.Type;import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;public class EnumSerializer implements JsonSerializer,JsonDeserializer {// 对象转为Json时调用,实现JsonSerializer接口&＃64;Overridepublic JsonElement serialize(PackageState state, Type arg1,JsonSerializationContext arg2) {return new JsonPrimitive(state.ordinal());}// json转为对象时调用,实现JsonDeserializer接口&＃64;Overridepublic PackageState deserialize(JsonElement json, Type typeOfT,JsonDeserializationContext context) throws JsonParseException {if (json.getAsInt()

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;public class GsonTest6 {public static void main(String[] args) {GsonBuilder gsonBuilder &＃61; new GsonBuilder();gsonBuilder.registerTypeAdapter(PackageState.class,new EnumSerializer());Gson gson &＃61; gsonBuilder.create();PackageItem item &＃61; new PackageItem();item.setName("item_name");item.setSize("500M");item.setState(PackageState.UPDATING);// 这个 state是枚举值String s &＃61; gson.toJson(item);System.out.println(s);System.out.println("--------------------------------");PackageItem retItem &＃61; gson.fromJson(s, PackageItem.class);System.out.println(retItem);}
}


{"name":"item_name","state":2,"size":"500M"}
--------------------------------
PackageItem [name&＃61;item_name, size&＃61;500M, state&＃61;UPDATING]