與DOM比較而言，SAX是一種輕量型的方法。我們知道，在處理DOM的時候，我們需要讀入整個的XML文件，然後在記憶體中建立DOM樹，生成DOM樹上的每個Node物件。當文件比較小的時候，這不會造成什麼問題，但是一旦文件大起來，處理DOM就會變得相當費時費力。特別是其對於記憶體的需求，也將是成倍的增長，以至於在某些應用中使用DOM是一件很不划算的事（比如在applet中）。這時候，一個較好的替代解決方法就是SAX。

     SAX在概念上與DOM完全不同。它不同於DOM的文件驅動，它是事件驅動的，它並不需要讀入整個文件，而文件的讀入過程也就是SAX的解析過程。所謂事件驅動，是指一種基於回撥（callback）機制的程式執行方法。

     下面對這個xml檔案使用sax解析：

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <student id="1" group="1">
        <name>張三</name>
        <sex>男</sex>
        <age>18</age>
        <email>[email protected]</email>
        <birthday>1987-06-08</birthday>
        <memo>好學生</memo>
    </student>
    <student id="2" group="2">
        <name>李四</name>
        <sex>女</sex>
        <age>18</age>
        <email>
 
[email protected]</email>
        <birthday>1987-06-08</birthday>
        <memo>好學生</memo>
    </student>
    <student id="3" group="3">
        <name>小王</name>
        <sex>男</sex>
        <age>18</age>
        <email>[email protected]
 
</email>
        <birthday>1987-06-08</birthday>
        <memo>好學生</memo>
    </student>
    <student id="4" group="4">
        <name>小張</name>
        <sex>男</sex>
        <age>18</age>
        <email>[email protected]</email>
        <birthday>1987-06-08</birthday>
        <memo>好學生</memo>
    </student>
    <student id="5" group="5">
        <name>小明</name>
        <sex>男</sex>
        <age>18</age>
        <email>[email protected]</email>
        <birthday>1987-06-08</birthday>
        <memo>好學生</memo>
    </student>
</root>

public class Student {
    
    private int id;
    private int group;
    private String name;
    private String sex;
    private int age;
    private String email;
    private String memo;
    private String birthday;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public int getGroup() {
        return group;
    }
    public void setGroup(int group) {
        this.group = group;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getMemo() {
        return memo;
    }
    public void setMemo(String memo) {
        this.memo = memo;
    }
    public String getBirthday() {
        return birthday;
    }
    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }
    
}

import java.util.ArrayList;
import java.util.List;


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



/**
 * 功能描述:採用sax方式解析XML<br>
 * 
 * @author sxyx2008
 *
 */
public class SaxParseXml extends DefaultHandler{

    //存放遍歷集合
    private List<Student> list;
    //構建Student物件
    private Student student;
    //用來存放每次遍歷後的元素名稱(節點名稱)
    private String tagName;
    
    
    public List<Student> getList() {
        return list;
    }


    public void setList(List<Student> list) {
        this.list = list;
    }


    public Student getStudent() {
        return student;
    }


    public void setStudent(Student student) {
        this.student = student;
    }


    public String getTagName() {
        return tagName;
    }


    public void setTagName(String tagName) {
        this.tagName = tagName;
    }


    //只調用一次  初始化list集合  
    @Override
    public void startDocument() throws SAXException {
        list=new ArrayList<Student>();
    }
    
    
    //呼叫多次    開始解析
    @Override
    public void startElement(String uri, String localName, String qName,
            Attributes attributes) throws SAXException {
        if(qName.equals("student")){
            student=new Student();
            //獲取student節點上的id屬性值
            student.setId(Integer.parseInt(attributes.getValue(0)));
            //獲取student節點上的group屬性值
            student.setGroup(Integer.parseInt(attributes.getValue(1)));
        }
        this.tagName=qName;
    }
    
    
    //呼叫多次  
    @Override
    public void endElement(String uri, String localName, String qName)
            throws SAXException {
        if(qName.equals("student")){
            this.list.add(this.student);
        }
        this.tagName=null;
    }
    
    
    //只調用一次
    @Override
    public void endDocument() throws SAXException {
    }
    
    //呼叫多次
    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        if(this.tagName!=null){
            String date=new String(ch,start,length);
            if(this.tagName.equals("name")){
                this.student.setName(date);
            }
            else if(this.tagName.equals("sex")){
                this.student.setSex(date);
            }
            else if(this.tagName.equals("age")){
                this.student.setAge(Integer.parseInt(date));
            }
            else if(this.tagName.equals("email")){
                this.student.setEmail(date);
            }
            else if(this.tagName.equals("birthday")){
                this.student.setBirthday(date);
            }
            else if(this.tagName.equals("memo")){
                this.student.setMemo(date);
            }
        }
    }
}

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

import org.xml.sax.SAXException;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class Test {

	public static void main(String[] args) {
        SAXParser parser = null;
        try {
            //構建SAXParser
            parser = SAXParserFactory.newInstance().newSAXParser();
            //例項化  DefaultHandler物件
            SaxParseXml parseXml=new SaxParseXml();
            //載入資原始檔 轉化為一個輸入流
            InputStream stream=SaxParseXml.class.getClassLoader().getResourceAsStream("student.xml");
            //呼叫parse()方法
            parser.parse(stream, parseXml);
            //遍歷結果
            List<Student> list=parseXml.getList();
            for(Student student:list){
                System.out.println("id:"+student.getId()+"\tgroup:"+student.getGroup()+"\tname:"+student.getName()+"\tsex:"+student.getSex()+"\tage:"+student.getAge()+"\temail:"+student.getEmail()+"\tbirthday:"+student.getBirthday()+"\tmemo:"+student.getMemo());
            }
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
}