Xerces 简明教程
SAX Parser - Parse XML Document
Demo Example
下面是需要解析的输入 xml 文件 −
<?xml version = "1.0"?>
<class>
<student rollno = "393">
<firstname>Dinkar</firstname>
<lastname>Kad</lastname>
<nickname>Dinkar</nickname>
<marks>85</marks>
</student>
<student rollno = "493">
<firstname>Vineet</firstname>
<lastname>Gupta</lastname>
<nickname>Vinni</nickname>
<marks>95</marks>
</student>
<student rollno = "593">
<firstname>Jasvir</firstname>
<lastname>Singh</lastname>
<nickname>Jazz</nickname>
<marks>90</marks>
</student>
</class>
UserHandler.java
package com.tutorialspoint.xml;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class UserHandler extends DefaultHandler {
boolean bFirstName = false;
boolean bLastName = false;
boolean bNickName = false;
boolean bMarks = false;
@Override
public void startElement(String uri,
String localName, String qName, Attributes attributes) throws SAXException {
if (qName.equalsIgnoreCase("student")) {
String rollNo = attributes.getValue("rollno");
System.out.println("Roll No : " + rollNo);
} else if (qName.equalsIgnoreCase("firstname")) {
bFirstName = true;
} else if (qName.equalsIgnoreCase("lastname")) {
bLastName = true;
} else if (qName.equalsIgnoreCase("nickname")) {
bNickName = true;
} else if (qName.equalsIgnoreCase("marks")) {
bMarks = true;
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
if (qName.equalsIgnoreCase("student")) {
System.out.println("End Element :" + qName);
}
}
@Override
public void characters(char ch[], int start, int length) throws SAXException {
if (bFirstName) {
System.out.println("First Name: " + new String(ch, start, length));
bFirstName = false;
} else if (bLastName) {
System.out.println("Last Name: " + new String(ch, start, length));
bLastName = false;
} else if (bNickName) {
System.out.println("Nick Name: " + new String(ch, start, length));
bNickName = false;
} else if (bMarks) {
System.out.println("Marks: " + new String(ch, start, length));
bMarks = false;
}
}
}
SAXParserDemo.java
package com.tutorialspoint.xml;
import java.io.File;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class SAXParserDemo {
public static void main(String[] args){
try {
File inputFile = new File("input.txt");
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
UserHandler userhandler = new UserHandler();
saxParser.parse(inputFile, userhandler);
} catch (Exception e) {
e.printStackTrace();
}
}
}
class UserHandler extends DefaultHandler {
boolean bFirstName = false;
boolean bLastName = false;
boolean bNickName = false;
boolean bMarks = false;
@Override
public void startElement(String uri,
String localName, String qName, Attributes attributes) throws SAXException {
if (qName.equalsIgnoreCase("student")) {
String rollNo = attributes.getValue("rollno");
System.out.println("Roll No : " + rollNo);
} else if (qName.equalsIgnoreCase("firstname")) {
bFirstName = true;
} else if (qName.equalsIgnoreCase("lastname")) {
bLastName = true;
} else if (qName.equalsIgnoreCase("nickname")) {
bNickName = true;
} else if (qName.equalsIgnoreCase("marks")) {
bMarks = true;
}
}
@Override
public void endElement(String uri,
String localName, String qName) throws SAXException {
if (qName.equalsIgnoreCase("student")) {
System.out.println("End Element :" + qName);
}
}
@Override
public void characters(char ch[],
int start, int length) throws SAXException {
if (bFirstName) {
System.out.println("First Name: " + new String(ch, start, length));
bFirstName = false;
} else if (bLastName) {
System.out.println("Last Name: " + new String(ch, start, length));
bLastName = false;
} else if (bNickName) {
System.out.println("Nick Name: " + new String(ch, start, length));
bNickName = false;
} else if (bMarks) {
System.out.println("Marks: " + new String(ch, start, length));
bMarks = false;
}
}
}
以上程序将生成以下结果:
Roll No : 393
First Name: Dinkar
Last Name: Kad
Nick Name: Dinkar
Marks: 85
End Element :student
Roll No : 493
First Name: Vineet
Last Name: Gupta
Nick Name: Vinni
Marks: 95
End Element :student
Roll No : 593
First Name: Jasvir
Last Name: Singh
Nick Name: Jazz
Marks: 90
End Element :student