CODEWITHSUNDEEP
javajsonserializationenumsjackson
Mohammad Siavashi
Mohammad Siavashi

Reputation: 1262

can't deserialize an Object to its original Type using jackson @JsonTypeInfo annotation

im Trying to serialize an object ( from an Enum ) in the client-side of my application and deserialize it in the other side ( server-side ) to the same Object using jackson . i have this enum in my client-side :

@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "@type")
public enum Request{
    Signup,
    Login
}

which using the @jsonTypeInfo annotaion of jackson .

and on the server-side im doing this to deserialize the object :

ObjectMapper mapper = new ObjectMapper();
    final JsonNode jsonNode;
    jsonNode = mapper.readTree(json);  //json is the return String from the convertObjectToJson(Request.Signup);

    //i get the error on this line
    String type = jsonNode.get("@type").asText();

as i've commented in the code above im getting the NullException on the jsonNode.get("@type").asText() while the json is : [ "Request", "Signup" ]

and this is the function that serialize the objects :

public static String convertObjectToJson(Object object) throws IOException {
        ObjectWriter objectWriter = new ObjectMapper().writer().withDefaultPrettyPrinter();
        String json = objectWriter.writeValueAsString(object);
        return json;
    }

where is the problem ?

Upvotes: 0

Views: 645

Answers (1)

Francisco Hernandez
Francisco Hernandez

Reputation: 2468

Jackson by default will represent java enums as simple strings and for that reason you are unable to deserialize the object

Take a look here, it could help: http://www.baeldung.com/jackson-serialize-enums

Upvotes: 2

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