杰克逊反序列化为默认子类型

Question

类 地址位置 和 机场位置 从位置扩展。当 json 中的"type"字段作为"地址"或"机场"出现时，jackson 分别正确地将其反序列化为 AddressLocation 和 AirportLocation 类。当"类型"不存在时，杰克逊不知道如何反序列化对象。有没有办法配置杰克逊，如果"类型"不存在或为空，则使用默认类型为"地址"？

从以下内容中删除了 getter、setter 和构造函数

@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。如果是这种情况，那是因为框架管理的杰克逊不是由你的代码管理的。您可以通过注入自定义反序列化程序，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);
...
}