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I'm using FasterXML to serialize POJO. I want to serialize a list of my POJO. When serialize a signle POJO I get the expected xml (there's one problem --> question 2) Here's my code:

List<Movie> movies = new ArrayList<>();
// add movies
JacksonXmlModule module = new JacksonXmlModule();
module.setDefaultUseWrapper(false);
xmlMapper = new XmlMapper(module);
xmlMapper.disable(MapperFeature.AUTO_DETECT_CREATORS,
            MapperFeature.AUTO_DETECT_FIELDS,
            MapperFeature.AUTO_DETECT_GETTERS,
            MapperFeature.AUTO_DETECT_IS_GETTERS,
            MapperFeature.AUTO_DETECT_SETTERS,
            MapperFeature.USE_GETTERS_AS_SETTERS);
String xml = xmlMapper.writeValueAsString(movies);

I get this:

<ArrayList>
    <item imdbID="tt0077687" title="The Hobbit" year="1977"/>
</ArrayList>

Here's what I want:

<movies>
    <movie imdbID="tt0077687" title="The Hobbit" year="1977"/>
    <movie imdbID="tt0077687" title="title2" year="1977"/>
</movies>

or 

<movie imdbID="tt0077687" title="The Hobbit" year="1977"/>
<movie imdbID="tt0077687" title="title2" year="1977"/>

  1. When I serialize a movie I get this:

Is it possible to get this:

<movie imdbID="tt0077687" title="The Hobbit" year="1977"><movie>
Hunsu
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2 Answers2

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As a general rule, do not try serializing List, Maps or arrays directly as the root-level value: always use a Bean (POJO). Properties may be of any types, recursively.

The problem is that Java type erasure make things problematic for collection and Map types in general (even with JSON); but there are additional problems for XML.

So while it may seem unnecessary, I have found it safest to have a simple Object as the root value, even if it's only something like:

public class Response {
   public List<Movie> movies;
}

Having said that, to change the name of root element can be done multiple ways. One possibility is to use Jackson annotation @JsonRootName (despite "Json" in there, it applies to all formats).

Or, you can use ObjectWriter, override root name with:

String xml mapper.writer().withRootName("movies").writeValueAsString(movies);
StaxMan
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  • Ok thanks. What about my second question do you have an idea? – Hunsu Mar 26 '15 at 21:05
  • If you mean empty XML tags vs start/end element, that is possible by configuring underlying XML library (at least if you are using Woodstox). If you mean changing name of item element, it is trickier. – StaxMan Mar 26 '15 at 21:07
  • I just use FasterXML that Woodstox but I don't know how to configure it. I just added woodstox dependency to my pom. – Hunsu Mar 26 '15 at 21:13
  • Understood. What I meant is that you can construct `XmlMapper` with specific `XMLInputFactory` and/or `XMLOutputFactory` instances (these are Stax API abstractions, implemented by Woodstox with its `WstxInputFactory` and `WstxOutputFactory`) to use. And you can pre-configure said factories with different properties. But since I do not remember what output setting would work for forcing writing out of empty elements I guess it's moot point. :) – StaxMan Mar 27 '15 at 19:51
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You'll probably have to annotate your movies variable. (And likely either pull it out into a field or declare an object to encapsulate it.) Check the annotations on this page to see if something matches. Sorry I can't be more specific.

https://github.com/FasterXML/jackson-annotations/wiki/Jackson-Annotations

Barett
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