This example assumes the following class is already on your CLASSPATH:
XmlExamples.groovy
class XmlExamples {
static def CAR_RECORDS = '''
<records>
<car name='HSV Maloo' make='Holden' year='2006'>
<country>Australia</country>
<record type='speed'>Production Pickup Truck with speed of 271kph</record>
</car>
<car name='P50' make='Peel' year='1962'>
<country>Isle of Man</country>
<record type='size'>Smallest Street-Legal Car at 99cm wide and 59 kg in weight</record>
</car>
<car name='Royale' make='Bugatti' year='1931'>
<country>France</country>
<record type='price'>Most Valuable Car at $15 million</record>
</car>
</records>
'''
}
Here is an example of using DOM4J with Groovy to process an existing XML file:
// require(groupId:'dom4j', artifactId:'dom4j', version:'1.6.1') import org.dom4j.io.SAXReader def reader = new StringReader(XmlExamples.CAR_RECORDS) def records = new SAXReader().read(reader).rootElement def messages = [] records.elementIterator().each{ car -> def make = car.attributeValue('make') def country = car.elementText('country') def type = car.element('record').attributeValue('type') messages << make + ' of ' + country + ' has a ' + type + ' record' } assert messages == [ 'Holden of Australia has a speed record', 'Peel of Isle of Man has a size record', 'Bugatti of France has a price record' ]
DOM4J also supports a streaming mode which lets you manually prune parts of the DOM tree during processing to facilitate processing large documents. Here is an example which uses DOM4J in that mode:
// require(groupId:'dom4j', artifactId:'dom4j', version:'1.6.1') import org.dom4j.io.SAXReader import org.dom4j.* class PruningCarHandler implements ElementHandler { def messages = [] public void onStart(ElementPath path) { } public void onEnd(ElementPath path) { def car = path.current def make = car.attributeValue('make') def country = car.elementText('country') def type = car.element('record').attributeValue('type') messages << make + ' of ' + country + ' has a ' + type + ' record' car.detach() // prune the tree } } def xml = new StringReader(XmlExamples.CAR_RECORDS) def reader = new SAXReader() def handler = new PruningCarHandler() reader.addHandler('/records/car', handler) reader.read(xml) assert handler.messages == [ 'Holden of Australia has a speed record', 'Peel of Isle of Man has a size record', 'Bugatti of France has a price record' ]
In the above example, we actually did the processing as part of the ElementHandler. Instead, we could have used a hybrid approach which just pruned away parts of the tree we weren't interested in and then performed tree-walking/navigation style coding after that.
