Question

我正在处理一个使用json并将其转换为Objects的代码。例如，说我的json响应如下： -

String carJson =“{\”car \“：[{\”brand \“：\”Mercedes \“，\”doors \“：5}，{\”brand \“：\”Tata \“， \“门\”：4}]}“;

实际上是它的汽车阵列。

我在下面编写了代码，将其反序列化为Java Objects： -

    ObjectMapper objectMapper = new ObjectMapper();

            objectMapper.enable(SerializationFeature.INDENT_OUTPUT);

            List<Car> jsonToCarList = objectMapper.readValue(carJson, new TypeReference<List<Car>>() {}); 
            jsonToCarList.forEach(System.out::println);

这是我的汽车类： -

public class Car {        
            @JsonProperty("car")
            private List<CarType> car;

        public Car(@JsonProperty("car") List<CarType> car) {
            this.car = car;
        }

        @JsonProperty("car")
        public List<CarType> getCar() {
            return car;
        } }

CarType如下： -

class CarType {

@JsonProperty("brand")
private String brand;

@JsonProperty("doors")
private String doors;

public CarType(String brand, String doors) {
    this.brand = brand;
    this.doors = doors;
}

public CarType() {

}

@JsonProperty("brand")
public String getBrand() {
    return brand;
}

@JsonProperty("doors")
public String getDoors() {
    return doors;
}
}

这里有什么不对，我没有得到。我收到以下错误： -

Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token
 at [Source: {"car" : [{ "brand" : "Mercedes", "doors" : 5 },{ "brand" : "Tata", "doors" : 4 }] }; line: 1, column: 1]
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:148)
    at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:762)
    at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:758)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.handleNonArray(CollectionDeserializer.java:275)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:216)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:206)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:25)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3066)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2168)

Answer 1

您正在尝试反序列化为错误的类型：

List<Car> jsonToCarList = objectMapper.readValue(carJson, new TypeReference<List<Car>>() {});

应该是

Car jsonToCar = objectMapper.readValue(carJson, Car.class);

您想要的列表位于您发布的Car类中。

无法反序列化对Arrya Of Objects的JSON响应

1 个答案: