Using JAXB to unmarshal/marshal a List<String>

User1 picture User1 · Oct 21, 2009 · Viewed 125.5k times · Source

I'm trying to create a very simple REST server. I just have a test method that will return a List of Strings. Here's the code:


@GET
@Path("/test2")
public List test2(){
    List list=new Vector();
    list.add("a");
    list.add("b");
    return list;
}

It gives the following error:

SEVERE: A message body writer for Java type,
class java.util.Vector, and MIME media type,
application/octet-stream, was not found

I was hoping JAXB had a default setting for simple types like String, Integer, etc. I guess not. Here's what I imagined:


<Strings>
  <String>a</String>
  <String>b</String>
</Strings>

What's the easiest way to make this method work?

Answer

User1 picture User1 · Oct 21, 2009

I used @LiorH's example and expanded it to:


@XmlRootElement(name="List")
public class JaxbList<T>{
    protected List<T> list;

    public JaxbList(){}

    public JaxbList(List<T> list){
        this.list=list;
    }

    @XmlElement(name="Item")
    public List<T> getList(){
        return list;
    }
}

Note, that it uses generics so you can use it with other classes than String. Now, the application code is simply:


    @GET
    @Path("/test2")
    public JaxbList test2(){
        List list=new Vector();
        list.add("a");
        list.add("b");
        return new JaxbList(list);
    }

Why doesn't this simple class exist in the JAXB package? Anyone see anything like it elsewhere?