我有一个Android应用程序，它打电话做休息api。 它返回一个餐馆列表。每家餐厅都有类别列表。每个类别都可以有多种菜肴。
当我反序列化这个列表时，我有很好的ArrayList of Restaurants，每个Restaurant也有一个ArrayList类别，但是在Category类中，Dishes的ArrayList是null。
有没有人知道如何解决这个问题？
JSON响应:(它实际上是ServiceResponse类型的对象）
{
"requestToken" : 0,
"responseCode" : 2,
"objectType" : "com.test.Restaurant",
"error" : null,
"data" : [ {
"id" : 1,
"name" : "Name",
"addressCity" : "Warszawa",
"addressStreet" : "Kopernika",
"addressStreetNumber" : "4",
"addressApartmentNumber" : "17",
"categories" : [ {
"id" : 1,
"restaurantId" : 1,
"name" : "Breakfast",
"description" : "Description",
"dishes" : [ {
"id" : 11,
"categoryId" : 1,
"name" : "Dish 1",
"description" : "Descr",
"price" : 8.99,
"photoId" : 51
}, {
"id" : 21,
"categoryId" : 1,
"name" : "Dish 2",
"description" : "Descr",
"price" : 6.99,
"photoId" : 41
}, {
"id" : 31,
"categoryId" : 1,
"name" : "Dish 3",
"description" : "Descr",
"price" : 14.99,
"photoId" : 61
} ]
}, {
"id" : 2,
"restaurantId" : 1,
"name" : "Obiady",
"description" : "Opis kategorii",
"dishes" : [ {
"id" : 41,
"categoryId" : 2,
"name" : "Danie 4",
"description" : "Descr",
"price" : 6.99,
"photoId" : 0
}, {
"id" : 61,
"categoryId" : 2,
"name" : "Danie 5",
"description" : "Descr",
"price" : 8.0,
"photoId" : 0
}, {
"id" : 101,
"categoryId" : 2,
"name" : "Nowy obiad",
"description" : "",
"price" : 111.0,
"photoId" : 0
} ]
}, {
"id" : 3,
"restaurantId" : 1,
"name" : "Pasta",
"description" : "Opis kategorii",
"dishes" : [ ]
}, {
"id" : 4,
"restaurantId" : 1,
"name" : "Przystawki",
"description" : "Opis kategorii",
"dishes" : [ ]
}, {
"id" : 11,
"restaurantId" : 1,
"name" : "Some category",
"description" : "test",
"dishes" : [ ]
}, {
"id" : 51,
"restaurantId" : 1,
"name" : "Sushi",
"description" : "",
"dishes" : [ ]
} ]
}]
}
解析杰克逊的结果：
ServiceResponse response = getServiceOutput(params, httpMethod);
if(response.getData() != null && response.getData().size() > 0) {
try {
// convert data array from object to class defined in objectType (in JSON)
ObjectMapper mapper = new ObjectMapper();
Class clazz = Class.forName( response.getObjectType() );
ArrayList list = (mapper.convertValue(response.getData(),
TypeFactory.defaultInstance().constructCollectionType(
ArrayList.class, clazz)));
broadcastIntent.putExtra("result", list);
broadcastIntent.putExtra("response_code", ServiceResponse.OK);
} catch (Exception e) {
broadcastIntent.putExtra("response_code", ServiceResponse.ERROR);
e.printStackTrace();
}
}
答案 0 :(得分：1)
这对我有用。我将类（Response，Restaurant等）声明为静态的原因是因为Jackson无法反序列化非静态内部类。
public class Test {
static String jsonString = "{ \"requestToken\":0, \"responseCode\":2, \"objectType\":\"com.test.Restaurant\", \"error\":null, \"data\":[ { \"id\":1, \"name\":\"Name\", \"addressCity\":\"Warszawa\", \"addressStreet\":\"Kopernika\", \"addressStreetNumber\":\"4\", \"addressApartmentNumber\":\"17\", \"categories\":[ { \"id\":1, \"restaurantId\":1, \"name\":\"Breakfast\", \"description\":\"Description\", \"dishes\":[ { \"id\":11, \"categoryId\":1, \"name\":\"Dish 1\", \"description\":\"Descr\", \"price\":8.99, \"photoId\":51 }, { \"id\":21, \"categoryId\":1, \"name\":\"Dish 2\", \"description\":\"Descr\", \"price\":6.99, \"photoId\":41 }, { \"id\":31, \"categoryId\":1, \"name\":\"Dish 3\", \"description\":\"Descr\", \"price\":14.99, \"photoId\":61 } ] }, { \"id\":2, \"restaurantId\":1, \"name\":\"Obiady\", \"description\":\"Opis kategorii\", \"dishes\":[ { \"id\":41, \"categoryId\":2, \"name\":\"Danie 4\", \"description\":\"Descr\", \"price\":6.99, \"photoId\":0 }, { \"id\":61, \"categoryId\":2, \"name\":\"Danie 5\", \"description\":\"Descr\", \"price\":8.0, \"photoId\":0 }, { \"id\":101, \"categoryId\":2, \"name\":\"Nowy obiad\", \"description\":\"\", \"price\":111.0, \"photoId\":0 } ] }, { \"id\":3, \"restaurantId\":1, \"name\":\"Pasta\", \"description\":\"Opis kategorii\", \"dishes\":[ ] }, { \"id\":4, \"restaurantId\":1, \"name\":\"Przystawki\", \"description\":\"Opis kategorii\", \"dishes\":[ ] }, { \"id\":11, \"restaurantId\":1, \"name\":\"Some category\", \"description\":\"test\", \"dishes\":[ ] }, { \"id\":51, \"restaurantId\":1, \"name\":\"Sushi\", \"description\":\"\", \"dishes\":[ ] } ] } ] }";
public static void main(String[] args) throws Exception {
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false);
Response res = mapper.readValue(jsonString, Response.class);
}
public static class Response {
public String requestToken;
public List<Restaurant> data;
public Response(){}
public String getRequestToken() {
return requestToken;
}
public void setRequestToken(String requestToken) {
this.requestToken = requestToken;
}
public List<Restaurant> getData() {
return data;
}
public void setData(List<Restaurant> data) {
this.data = data;
}
}
public static class Restaurant {
public List<Category> categories;
public List<Category> getCat() {
return categories;
}
public void setCat(List<Category> categories) {
this.categories = categories;
}
public Restaurant(){}
}
public static class Category {
public List<Dish> dishes;
public Category(){}
public List<Dish> getDishes() {
return dishes;
}
public void setDishes(List<Dish> dishes) {
this.dishes = dishes;
}
}
public static class Dish {
public String id, categoryId, name, description;
public float price;
public int photoId;
public Dish(){}
}
}