Loading settings from XML file into a Java class

I have an XML file containing a bunch of simulation settings (partial example below). I would like to load these settings into a Java class, so that the settings are available later without having to write cumbersome DOM/XPath jargon (and import the associated packages) every time I (or another programmer who isn't fluent in DOM/XPath) want to access a specific setting.

Right now I set up a number of sub-classes that represent each level of information in the XML tree, and "manually" parse out the info to all these sub-classes. The result is, for example, that if I want to get Direction number 3, I can write:

settings.setup.directions[3]

I guess this works ok, but it sure feels rigid.

Is there a smarter way of doing this? Should we just stick to the DOM and skip this conversion business? (Please no!)

Note that I am not looking for instructions on how to load an XML file -- I know how to load it into a DOM document and parse it with XPath.

<?xml version="1.0"?>
<Settings>
    <Identity>
        <JobNumber>1234567</JobNumber>
        <SimulationName>MyTest</SimulationName>
    </Identity>
    <PreProcessing >
        <Tolerance&开发者_JAVA技巧gt;0.01</Tolerance>
    </PreProcessing >
    <PreprocessedInputData>
        <PreChewedThing></PreChewedThing>
        <OtherThing></OtherThing>
    </PreprocessedInputData>
    <Setup>
        <DomainExtent>
            <XMin>260</XMin>
            <XMax>290</XMax>
            <YMin>523</YMin>
            <YMax>565</YMax>
        </DomainExtent>
        <Directions>
            <Direction Index = "1">0</Direction>
            <Direction Index = "2">10</Direction>
            <Direction Index = "3">20</Direction>
            <Direction Index = "4">30</Direction>
        </Directions>
    </Setup>
</Settings>

You can use JAXB for this purpose, it is meant to bind XML to Java classes. There is a useful guide on http://jaxb.java.net/guide/ and a tutorial on http://jaxb.java.net/tutorial/

If you have flexibility over the layout of the XML file, and don't especially need to use a settings class with JAXB, try Commons Configuration:

Creating an XML settings file is as easy as:

    XMLConfiguration configCreate = new XMLConfiguration();
    configCreate.setFileName("settings.xml");
    configCreate.addProperty("somesetting", "somevalue");
    configCreate.save();

Reading from the XML settings file:

    XMLConfiguration configRead = new XMLConfiguration("settings.xml");
    String settingValue = configRead.getString("somesetting");

See http://commons.apache.org/configuration/

In my opinion, the best and simpliest way is using Java and XPath. This is an example:

<settings>
 <type>jdbc-mysql</tipus>
 <usr>usr</usr>
 <pass>pass</pass>
 <url>jdbc:mysql://192.168.1.123:3306/notifications_db</url>
 <schema>notificacions_db</schema>
 <date_format>yyyy-MM-dd HH:mm:ss</date_format>
 <prefix_package>false</prefix_package>
 <use_ssl>false</use_ssl>
 <auto_reconnect>true</auto_reconnect></settings>

Java main class Example:

public static void main(String[] args) {

    XPath xpath = XPathFactory.newInstance().newXPath();
    String xpathExpression = "/settings";
    InputSource inputSource = new InputSource("basedao-settings.xml");

    try {

        NodeList lstRoot = (NodeList) xpath.compile(xpathExpression).evaluate(inputSource, XPathConstants.NODESET);
        NodeList lstChilds = lstRoot.item(0).getChildNodes();

        for (int i = 0; i < lstChilds.getLength(); i++) {

            System.out.println(lstChilds.item(i).getLocalName());
            System.out.println(lstChilds.item(i).getTextContent());

        }

    } catch (XPathExpressionException e) {
        e.printStackTrace();
    }

}