jaxb single element in array

Question

I'm using JAXB/Jersey (1.3) to convert java to json in a REST API. The java class I'm returning is like:

public class MyClass {  
  List<String> myTags;
  public List<String> getMyTags() {
    return myTags;
  }
}

My problem is that if there is only a single element in the list myTags, then the data is converted to json as a string object, not an array of strings. That is, I get:

{
  "myTags": "myString"
}

What I want is:

{
   "myTags": ["myString"]
}

Anyone know whats up ?

Which library are you using for converting JAXB annotated classes to JSON? — Luciano Fiandesio, Apr 12 '11 at 20:50
Yeah, but which library do you use to convert the class to JSON? JAXB converts classes to XML, you need another library to convert to JSON, such as Jettison or Jackson — Luciano Fiandesio, Apr 12 '11 at 21:05
I'm using Maven, and only specifying the jersey dependencies, so I'm not explicitly specifying a library. However, looking at the resulting WAR file created, I'm assuming that Jersey is pulling in Jackson as a dependency (v1.7.1). — Kevin, Apr 12 '11 at 21:16
Yep, its Jackson :- the dependencies are listed in here: http://download.java.net/maven/2/com/sun/jersey/jersey-json/1.6/jersey-json-1.6.pom — Kevin, Apr 12 '11 at 21:17
The link you have provided also has a dependency to Jettison, that has the problem you mentioned ( single element array rendered as non-array in Json). Can this help: http://jersey.576304.n2.nabble.com/Single-Element-Arrays-and-JSON-td5532105.html — Luciano Fiandesio, Apr 12 '11 at 21:22

score 7 · Accepted Answer · edited May 23 '17 at 10:34

7

As per Luciano's comments, the problem lies in the fact that Jersey wasn't using Jackson as the default JSON converter. I tried excluding Jettison from the pom dependency, but it still didn't resolve the issue. I found an answer to explicitly tell Jersey to use Jackson here:

How can I customize serialization of a list of JAXB objects to JSON?

edited May 23 '17 at 10:34

Community

1
1

answered Apr 13 '11 at 07:54

Kevin

11,521
22
81
103

score -1 · Answer 2 · answered Sep 30 '14 at 22:01

-1

I was facing the similar issue and found simple fix. Marking @JsonSerialize instead of @XmlRootElement has worked for me.

@JsonSerialize
public class MyClass {  
  List<String> myTags;
  public List<String> getMyTags() {
    return myTags;
  }
}

answered Sep 30 '14 at 22:01

Manju

39
3

jaxb single element in array

2 Answers2