Question

I’ll start directly with my question and later on I give more background information.

Simple: I hava a LinkedHashMap<String, String> and it represents a specific object.
What is the best way to convert it to that object?

I know that you can use generics to get through all elements and set the fields, but what is whit nested objects?

Background: I have a JAX-RS service that consumes JSON objects. My service handles different kind of objects and just represents an interface. So I don’t know which objects are coming from outside and which program is using my service.

At runtime I get the information via @Inject on my interface. The JAX-RS service stores the data from the client in an untyped Object and its done automatically (thats the LinkedHashMap<String, String>).

With my interface I want to provide a method like setObject and parameter should be a object of that type. I can handle all of this, but not the part where I convert the Object LinkedHashMap<String, String> to that specific object.

Example Structure:
Target Objects could like that

public class Document {
    private String title;
    private String id;
    private int version;
}

The LinkedHashMap looks like that

{title=some title, id=1, version=1}

Answer 1

You can create two classes

@XmlAccessorType(XmlAccessType.FIELD) 
public class Document {
    @XmlElement
    private String title;
    @XmlElement
    private String id;
    @XmlElement
    private int version;
}  


@XmlAccessorType(XmlAccessType.FIELD)
public class MapJson {
    @XmlElement
    private LinkedHashMap<String, String> documents; 
}  

and cobvert Object to JSON usingg
Jackson

new org.codehaus.jackson.map.ObjectMapper().writeValueAsString(instanceofMapJson);  

Google JSON

new com.google.gson.Gson().toJson(instanceofMapJson);  

PS. Using google json, you can remove xml annotations from your classes