[英]How should I pass this variable E to this class? Custom serializer GSON
I am following this tutorial in order to implement a custom serializer in Windows Azure Mobile Android. 我正在学习本教程,以便在Windows Azure Mobile Android中实现自定义序列化程序。 I am trying to use the code however I am getting an error with E variable.
我试图使用代码但是我收到了E变量的错误。
public class CollectionSerializer implements JsonSerializer<Collection>, JsonDeserializer<Collection>{
public JsonElement serialize(Collection collection, Type type,
JsonSerializationContext context) {
JsonArray result = new JsonArray();
for(E item : collection){
result.add(context.serialize(item));
}
return new JsonPrimitive(result.toString());
}
@SuppressWarnings("unchecked")
public Collection deserialize(JsonElement element, Type type,
JsonDeserializationContext context) throws JsonParseException {
JsonArray items = (JsonArray) new JsonParser().parse(element.getAsString());
ParameterizedType deserializationCollection = ((ParameterizedType) type);
Type collectionItemType = deserializationCollection.getActualTypeArguments()[0];
Collection list = null;
try {
list = (Collection)((Class<?>) deserializationCollection.getRawType()).newInstance();
for(JsonElement e : items){
list.add((E)context.deserialize(e, collectionItemType));
}
} catch (InstantiationException e) {
throw new JsonParseException(e);
} catch (IllegalAccessException e) {
throw new JsonParseException(e);
}
return list;
}
}
You possibly meant to declare your class like this: 你可能想要像这样声明你的类:
public class CollectionSerializer<E> implements JsonSerializer<Collection<E>>,
JsonDeserializer<Collection<E>> {
The first method could then become: 第一种方法可以成为:
public JsonElement serialize(Collection<E> collection, Type type,
JsonSerializationContext context) {
JsonArray result = new JsonArray();
for(E item : collection){
result.add(context.serialize(item));
}
return new JsonPrimitive(result.toString());
}
Alternatively, you can leave the class declaration as is and change your method to: 或者,您可以保留类声明,并将方法更改为:
public <E> JsonElement serialize(Collection<E> collection, Type type,
JsonSerializationContext context) {
JsonArray result = new JsonArray();
for(E item : collection){
result.add(context.serialize(item));
}
return new JsonPrimitive(result.toString());
}
Which one you need depends on your use case (whether a given CollectionSerializer
always expects the same type of collection or not). 您需要哪一个取决于您的用例(给定的
CollectionSerializer
是否总是期望相同类型的集合)。
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