SAX解析

//stu.xml
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<exam>
<student>
<name>张三</name>
<location>西安</location>
<grade>98</grade>
</student>
<student>
<name>李四</name>
<location>临潼</location>
<grade>59</grade>
</student>
</exam>

sax_study.java

package com.SAX;

import java.io.IOException;
import java.util.ArrayList;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import com.student.Student;

public class sax_study {

	public static void main(String[]args) throws ParserConfigurationException, SAXException, IOException
	{
			SAXParserFactory factory=SAXParserFactory.newInstance();
			SAXParser sp=factory.newSAXParser();
			XMLReader reader=sp.getXMLReader();
			BeanListHandler blh=	new BeanListHandler();
			
			reader.setContentHandler(blh);
			reader.parse("src/stu.xml");
			ArrayList al=blh.getStudents();
			for(int j=0;j<al.size();++j)
			{
				Student stu=(Student) al.get(j);
				System.out.println(stu.getName()+"---"+stu.getLocation()+"---"+stu.getGrade());
			}
	}
}
class BeanListHandler extends DefaultHandler
{
		ArrayList  list=new ArrayList();
		String current_tag=null;
		Student stu=null;
		public ArrayList getStudents()
		{
			return list;
		}
	@Override
	public void startElement(String uri, String localName, String qName,
			Attributes attributes) throws SAXException {
		if("student".equals(qName))       //避免空指针异常，所以把字符串变量放在后面
		{
			current_tag="student";
			stu=new Student();
		}
		else if("name".equals(qName))
		{
			current_tag="name";
		}
		else if("location".equals(qName))
		{
			current_tag="location";
		}
		else if("grade".equals(qName))
		{
			current_tag="grade";
		}
	}

	@Override
	public void characters(char[] ch, int start, int length)
			throws SAXException {
			if("location".equals(current_tag ) )
			{
				stu.setLocation(new String(ch,start,length));
			}
			else if("grade".equals(current_tag))
			{
				stu.setGrade(Integer.parseInt(new String(ch,start,length)));
			}
			else	if("name".equals(current_tag))
			{
				stu.setName(new String(ch,start,length));
			}
	}
	
		@Override
	public void endElement(String uri, String localName, String qName)
			throws SAXException {
			if("student".equals(qName))
			{
				list.add(stu);
				stu=null;
			}
			current_tag=null;    //这句话千万不可省略，省略会报空指针异常，
                                             //因为遇到结束标签时，stu被置为null，然后遇到空白文本，stu调用set方法，报错
	}
}

Student.java

package com.student;

public class Student {
	private  String name;
	private  String location;
	private int grade;
	public Student(String na,String lo,int gr)
	{
		name=na;
		location=lo;
		grade=gr;
	}
	public Student()
	{
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getLocation() {
		return location;
	}
	public void setLocation(String location) {
		this.location = location;
	}
	public int getGrade() {
		return grade;
	}
	public void setGrade(int grade) {
		this.grade = grade;
	}
}

这种解析方式，在实际开发过程中比较常用应当掌握。