Jackson 枚举反序列化委托

Question

Is there a way to deserialize an enum which works for both the name and the object notation. I do want to keep the Shape as object for the deserialization though

eg This works for "type": {"name":"MYENUM"}, but what would I need to add to have it also work for "type": "MYENUM"

@JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum MyType {

    @JsonProperty("MYENUM")
    MYENUM("MyEnum")

    public final String name = name();

    MyType(String value) {
        this.value = value;
    }

    @JsonCreator
    public static MyType deserialize (@JsonProperty("name") String name) {
        return MyType.valueOf(name);
    }
}

Have tried adding a delegate like this

    @JsonCreator(mode=JsonCreator.Mode.DELEGATING)
    public static MyType deserializeString (String name) {
        return MyType.valueOf(name);
    }

Answer 1

One way to solve your problem is a custom deserializer extending StdDeserializer and inside of it check if your json file is in the form of "type": {"name":"MYENUM"} or {"type": "MYENUM"} . This checking can be obtained with the JsonNode.html#isObject method :

public class MyTypeDeserializer extends StdDeserializer<MyType> {

    public MyTypeDeserializer() {
        this(null);
    }

    public MyTypeDeserializer(Class<?> vc) {
        super(vc);
    }

    @Override
    public MyType deserialize(JsonParser jp, DeserializationContext dc) throws IOException, JsonProcessingException {
        JsonNode root = jp.getCodec().readTree(jp);
        JsonNode nodeType = root.get("type");
        String name = nodeType.isObject() ? nodeType.get("name").asText() : nodeType.asText();
        return MyType.valueOf(name);
    }

}

Then you can annotate your MyType enum with the @JsonDeserialize(using = MyTypeDeserializer.class) deleting your deserialize method like below :

@JsonDeserialize(using = MyTypeDeserializer.class)
@JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum MyType { //omitted fields and methods for brevity }