Question

Problem

Given the following XML configuration file:

<main>
  <name>JET</name>
  <maxInstances>5</maxInstances>
  <parameters>
    <a>1</a>
    <b>
      <b1>test1</b1>
      <b2>test2</b2>
    </b>
  </parameters>
</main>

I need to extract the value of the name and maxInstances elements and then the whole inner text of the parameters element. e.g.

name = "JET"
maxInstances = 5
parameters = "<a>1</a><b><b1>test1</b1><b2>test2</b2></b>"

Ultimately the parameters block can contain any well formed XML.

Attempted Solution

The following code works for name and maxInstances but not parameters:

@XmlRootElement(name="main")
public class Main {

    @XmlElement(name="name", required="true")
    private String name;

    @XmlElement(name="maxInstances", required="true")
    private Integer maxInstances;

    @XmlElement(name="parameters")
    private String parameters;

}

I’ve tried looking at solutions based on the following ideas but can’t find something appropriate.

Is there a different type I can use for the parameters object representing the XML Tree that I could parse to produce a string? e.g.

@XmlElement(name="parameters")
private XmlNodeObject parametersNode;

public String getParameters() {
    // Collapse node to single line of text
    return innerText;
}

Or do I need to use some different kind of annotation?

@XmlSpecialAnnotation(...)
@XmlElement(name="parameters")
private String parameters;

Do I need to switch to a different style of parser? Is it a good/bad idea to use two styles of parser?

Answer 1

The closest you could come is to map ‘parameters’ to a DOM tree, by declaring the variable to be org.w3c.dom.Node. (Actually, declaring a JAXBElement).

For details, see http://jaxb.java.net/guide/Avoid_strong_databinding.html. That gives you the schema-first prescription, you can see how to start from java by running that schema through xsd2java and looking at the output.

To get a string you’ll have to serialize from the DOM.

Or, even more specifically:

this page here describes xsd:any processing, and thus

  @XmlAnyElement
  public List<Element> getParameters();

Where Element is the DOM interface.