Android 解析XML 之SAX

SAX是一种占用内存少且解析速度快的解析器，它采用的是事件启动，它不需要解析完整个文档，而是按照内容顺序 看文档某个部分是否符合xml语法，如果符合就触发相应的事件，所谓的事件就是些回调方法（callback）,这些方法 定义在ContentHandler中，下面是其主要方法：

startDocument:当遇到文档的时候就触发这个事件 调用这个方法 可以在其中做些预处理工作

startElement: (String namespaceURI,String localName,String qName,Attributes atts)当遇开始标签的时候就会触发这个方法。

endElement（String uri,String localName,String name）：当遇到结束标签时触发这个事件，调用此法可以做些善后工作。

charachers(char [] ch,int start,int length):当遇到xml内容时触发这个方法，用new String(ch,start,length)可以接受内容。

1：创建SAXParserFactory对象

2: 根据SAXParserFactory.newSAXParser()方法返回一个SAXParser解析器

3：根据SAXParser解析器获取事件源对象XMLReader

4：实例化一个DefaultHandler对象

5：连接事件源对象XMLReader到事件处理类DefaultHandler中

6：调用XMLReader的parse方法从输入源中获取到的xml数据

7：通过DefaultHandler返回我们需要的数据集合。

首先在 res目录下新建一个raw文件夹，然后再里面么新建一个student.xml

student.xml

<?xml version="1.0" encoding="utf-8"?>
<stundets>
<student id="2009081315">
<name>饶伟</name>
<speciality>计算机科学与技术</speciality>
<qq>812200157</qq>
</student>

<student id="2009081316">
<name>小伟</name>
<speciality>网络工程</speciality>
<qq>812200156</qq>
</student>
<student id="2009081318">
<name>伟哥</name>
<speciality>软件工程</speciality>
<qq>812200158</qq>
</student>

</stundets>

Student.java

public class Student {

long Id;
String Name;
String Speciality;
long QQ;

public Student(long id, String name, String speciality, long qQ) {
super();
Id = id;
Name = name;
Speciality = speciality;
QQ = qQ;
}

public Student() {
super();
}

public long getId() {
return Id;
}

public String getName() {
return Name;
}

public long getQQ() {
return QQ;
}

public String getSpeciality() {
return Speciality;
}

public void setId(long id) {
Id = id;
}

public void setName(String name) {
Name = name;
}

public void setQQ(long qQ) {
QQ = qQ;
}

public void setSpeciality(String speciality) {
Speciality = speciality;
}

}

StudentHandler.java

package rw.Xml_SAX;

import java.util.List;

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

import android.util.Log;

public class StudentHandler extends DefaultHandler {

private String preTAG;
private List<Student> ListStudent;
private Student stu;

public StudentHandler() {
super();
}

public StudentHandler(List<Student> listStudent) {
super();
ListStudent = listStudent;
}

public void startDocument() throws SAXException {
// TODO Auto-generated method stub
Log.i("------>", "文档开始");
super.startDocument();
}

public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {

Log.i("localName-------->", localName);
preTAG=localName;
if ("student".equals(localName)) {
stu=new Student();
stu.setId(Long.parseLong(attributes.getValue(0)));

for (int i = 0; i < attributes.getLength(); i++) {
//Log.i("attributes-------->", attributes.getValue(i));
Log.i("attributes-------->",String.valueOf(stu.getId()));
}
}
super.startElement(uri, localName, qName, attributes);
}

public void endDocument() throws SAXException {

Log.i("------>", "文档结束");
super.endDocument();
}

public void endElement(String uri, String localName, String qName)
throws SAXException {
preTAG="";
if ("student".equals(localName)) {
ListStudent.add(stu);
Log.i("-------->", "一个元素解析完成");
}
super.endElement(uri, localName, qName);
}

public void characters(char[] ch, int start, int length)
throws SAXException {

String dateString;
if ("name".equals(preTAG)) {
dateString=new String(ch,start,length);
stu.setName(dateString);
Log.i("name=", stu.getName());
}else if ("speciality".equals(preTAG)) {
dateString=new String(ch,start,length);
stu.setSpeciality(dateString);
Log.i("speciality=", stu.getSpeciality());
}else if ("qq".equals(preTAG)) {
dateString=new String(ch,start,length);
stu.setQQ(Long.parseLong((dateString)));
Log.i("QQ=", String.valueOf(stu.getQQ()));
}

super.characters(ch, start, length);
}

}

XML_Sax1Activity.java（唯一的一个activity）

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

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Adapter;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class XMl_Sax1Activity extends Activity {
private Button button;
private TextView textView;
private ListView listView;
private List<String> list=new ArrayList<String>();
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button=(Button)findViewById(R.id.button1);
textView=(TextView)findViewById(R.id.textView1);
listView=(ListView) findViewById(R.id.listView1);
//InputSource xMLResourceString=new InputSource(XMl_Sax1Activity.this.getResources().openRawResource(R.raw.student));
button.setOnClickListener(new ButtonListener());
}

class ButtonListener implements OnClickListener{

@Override
public void onClick(View v) {

List<Student> students=parserXMl();
for (Iterator iterator = students.iterator(); iterator.hasNext();) {
Student student = (Student) iterator.next();
list.add(String.valueOf(student.getId())+" "+student.getName()+" "+student.getSpeciality()+" "+String.valueOf((student.getQQ())));
}

ArrayAdapter<String> adapter=new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, list);
listView.setAdapter(adapter);
}

}

private List<Student> parserXMl()
{
SAXParserFactory factory=SAXParserFactory.newInstance();
List<Student>students=null;
Student student=null;
try {
XMLReader reader=factory.newSAXParser().getXMLReader();
students=new ArrayList<Student>();
reader.setContentHandler(new StudentHandler(students));
reader.parse(new InputSource(XMl_Sax1Activity.this.getResources().openRawResource(R.raw.student)));
} catch (Exception e) {
// TODO: handle exception
}
return students;
}
}

布局文件main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>

<Button android:text="SAX解析" android:id="@+id/button1" android:layout_height="wrap_content" android:layout_width="match_parent"></Button>
<TextView android:text="" android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content"></TextView>
<ListView android:layout_height="wrap_content" android:id="@+id/listView1" android:layout_width="match_parent"></ListView>
</LinearLayout>

运行效果