技巧: 使用 XML 流解析器

import java.io.*;
import java.util.Iterator;
import javax.xml.namespace.QName;
import javax.xml.stream.*;
import javax.xml.stream.events.*;
public class ParseByEvent {
public static void main(String[] args)
throws FileNotFoundException, XMLStreamException {
// Use the reference implementation for the XML input factory
System.setProperty("javax.xml.stream.XMLInputFactory",
"com.bea.xml.stream.MXParserFactory");
// Create the XML input factory
XMLInputFactory factory = XMLInputFactory.newInstance();
// Create the XML event reader
FileReader reader = new FileReader("somefile.xml");
XMLEventReader r =
factory.createXMLEventReader(reader);
// Loop over XML input stream and process events
while(r.hasNext()) {
XMLEvent e = r.next();
processEvent(e);
}
}
/**
* Process a single XML event
* @param e - the event to be processed
*/
private static void processEvent(XMLEvent e) {
if (e.isStartElement()) {
QName qname = ((StartElement) e).getName();
String namespaceURI = qname.getNamespaceURI();
String localName = qname.getLocalPart();
Iterator iter = ((StartElement) e).getAttributes();
while (iter.hasNext()) {
Attribute attr = (Attribute) iter.next();
QName attributeName = attr.getName();
String attributeValue = attr.getValue();
}
}
if (e.isEndElement()) {
QName qname = ((EndElement) e).getName();
}
if (e.isCharacters()) {
String text = ((Characters) e).getData();
}
if (e.isStartDocument()) {
String version = ((StartDocument) e).getVersion();
String encoding = ((StartDocument) e).getCharacterEncodingScheme();
boolean isStandAlone = ((StartDocument) e).isStandalone();
}
}
}

import java.io.*;
import javax.xml.stream.*;
public class ParseByIterator {
public static void main(String[] args)
throws FileNotFoundException, XMLStreamException {
// Use reference implementation
System.setProperty(
"javax.xml.stream.XMLInputFactory",
"com.bea.xml.stream.MXParserFactory");
// Create an input factory
XMLInputFactory xmlif = XMLInputFactory.newInstance();
// Create an XML stream reader
XMLStreamReader xmlr =
xmlif.createXMLStreamReader(new FileReader("somefile.xml"));
// Loop over XML input stream and process events
while (xmlr.hasNext()) {
processEvent(xmlr);
xmlr.next();
}
}
/**
* Process a single event
* @param xmlr - the XML stream reader
*/
private static void processEvent(XMLStreamReader xmlr) {
switch (xmlr.getEventType()) {
case XMLStreamConstants.START_ELEMENT :
processName(xmlr);
processAttributes(xmlr);
break;
case XMLStreamConstants.END_ELEMENT :
processName(xmlr);
break;
case XMLStreamConstants.SPACE :
case XMLStreamConstants.CHARACTERS :
int start = xmlr.getTextStart();
int length = xmlr.getTextLength();
String text =
new String(xmlr.getTextCharacters(), start, length);
break;
case XMLStreamConstants.COMMENT :
case XMLStreamConstants.PROCESSING_INSTRUCTION :
if (xmlr.hasText()) {
String piOrComment = xmlr.getText();
}
break;
}
}
private static void processName(XMLStreamReader xmlr) {
if (xmlr.hasName()) {
String prefix = xmlr.getPrefix();
String uri = xmlr.getNamespaceURI();
String localName = xmlr.getLocalName();
}
}
private static void processAttributes(XMLStreamReader xmlr) {
for (int i = 0; i < xmlr.getAttributeCount(); i++)
processAttribute(xmlr, i);
}
private static void processAttribute(XMLStreamReader xmlr, int index) {
String prefix = xmlr.getAttributePrefix(index);
String namespace = xmlr.getAttributeNamespace(index);
String localName = xmlr.getAttributeName(index);
String value = xmlr.getAttributeValue(index);
}
}