CODEWITHSUNDEEP
javajsonjacksongson
EviL GaMer
EviL GaMer

Reputation: 123

Deserializing JSON object with dynamic JsonProperty without wrapper class using Jackson

I want to restructure an application so that it uses REST instead of an EJB3Factory which wasn't needed in the first place and only makes trouble with the new server.

Basically I have a class Request:

public class Request {
    public String name;
    public String id;
    public List<? extends someObject> list;

    // default constructor
    ...

    // non-default constructor
    public Request(String name, String id, List<T> list) {
        this.name = name;
        this.id = id;
        this.list = list;
    }

The Request gets created and using Gson made into a Json object:

Gson gson = new Gson();
String payload = gson.toJson(Request);

This then gets sent to the REST API on the server. There Jackson deserializes it. I do not have access to the Jackson implementation there and cannot change it to Gson.

What I am basically trying to do now is to get Jackson to use the non-default constructor to deserialize the object. I know I can annotate the non-default constructor like this:

@JsonCreator    
public Request(@JsonProperty("name") String name, @JsonProperty("id") 
        String id, @JsonProperty("list") List<T> list) {
    this.name = name;
    this.id = id;
    this.list = list;
}

The thing is though that the field name of list is set at runtime per reflection and the Gson object that is generated might have it as scenarioName1 for one and scenarioName2 for something else.

I have looked at the different solutions provided here on Stack Overflow but none of them could provide me with a solution for my problem. This seemed most helpful but I cannot under any circumstances use a wrapper property nor can I actually map all possibilities.

Anyone got any idea?

EDIT to include examples:

Example 1:

{"name":"someName","id":"first","someScenarioName":[{...}]}

Example 2:

{"name":"someOtherName","id":"second","differentScenarioName":[{...}]}

Since I'm out of town on business that is the best I can do with right now. It's basically the last field having a different name depending on which scenario was chosen beforehand.

Upvotes: 1

Views: 1450

Answers (2)

EviL GaMer
EviL GaMer

Reputation: 123

Okay, so I figured out what my problem was. There are other lists in the class and those were the trouble. After annotating each of them with @JsonProperty("theirRespectiveName") it worked like a charm... Now I have to annotate about 100 lines of code and solve some more problems.

Upvotes: 0

Eduardo Meneses
Eduardo Meneses

Reputation: 524

Maybe you can try take a look on Mapper Features. Sincerely I didn't try it yet because I'm at work and so on, but I will send now my example and maybe it can help you:

public class Request {
   public String name;
   public String id;
   public List<? extends T> list;

   // default constructor
   ...

   // non-default constructor
   public Request(String name, String id, List<T> list) {
      this.name = name;
      this.id = id;
      this.list = list;
   }
}

Then to deserialize the object:

ObjectMapper mapper = new ObjectMapper();
mapper.configure(MapperFeature.USE_ANNOTATIONS, false);
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
mapper.readValue(json, Request.class);

My try is because the deserialization by annotation is true by default, but once you don't have a "list" object most of time, it won't find the field there.

Upvotes: 1

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