杰克逊反序列化为默认子类型

Question

类从 Location 扩展而来的 AddressLocation 和 AirportLocation。当 'type' 字段作为 'ADDRESS' 或 'AIRPORT' 出现在 json 中时，jackson 正确地将其反序列化为 AddressLocation 和 AirportLocation 类。当 'type' 不存在时，jackson 不知道如何反序列化对象。有没有一种方法可以配置杰克逊，如果 'type' 不存在或为空，则使用默认类型 'ADDRESS'?

//移除了下面的getters、setters和constructors

@JsonInclude(value= JsonInclude.Include.NON_EMPTY)
@JsonIgnoreProperties(ignoreUnknown = true)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type", visible=false)
@JsonSubTypes({ 
        @JsonSubTypes.Type(value = AirportLocation.class, name = "AIRPORT"),
        @JsonSubTypes.Type(value = AddressLocation.class, name = "ADDRESS")
})

public abstract class Location {
    private List<Float> geoCoordinates;
    private String city;
    private String countryCode;  
}

public class AddressLocation extends Location {
    private String province;
    private String postalCode;
    private String streetAddress;

    public AddressLocation(final List<Float> geoCoordinates, final String city, final String countryCode,
                           final String province,
                           final String postalCode, final String streetAddress) {
        super(geoCoordinates, city, countryCode);
        this.province = province;
        this.postalCode = postalCode;
        this.streetAddress = streetAddress;
    }
}

public class AirportLocation extends Location {
 String airportCode;
}

我得到的错误是-

Missing type id when trying to resolve subtype of [simple type, class ***]: missing type id property 'type'
 at [Source: (String)"{"geo_coordinates":[1.17549435E-38],"city":"Whateverville","country_code":"WW"}"; line: 1, column: 79]

Answer 1

当 JSON 由客户端发送并由控制器等框架反序列化时，我遇到了类似的问题。如果是这样，那是因为 Jackson 管理的框架不是由您的代码管理的。您可以通过注入自定义反序列化器，也可以通过传输对象简单地控制代码中的所有实例初始化

@POST
public String createAddress(AddressLocationRequest requestObj) {

   AddressLocation address = new AddressLocation();
   BeanUtils.copyProperties(address, requestObj);
   ...
}

杰克逊反序列化为默认子类型

Jackson deserialization into default subtype

java

json

jackson

deserialization

json-deserialization