Android基础之XML解析
常用的三种XML解析方式分别是：SAX解析器，PULL解析器，以及DOM解析器
SAX解析器是基于事件的解析器，主要是围绕着事件触发，以及事件的处理器来进行的。SAX解析方式的特点是解析速度快，占用内存小，但一旦开始解析需要将真个目录解析完。
PULL解析器同样是基于事件的解析器，但我们需要自己获取产生的事件然后做相应的操作，而不像SAX那样由处理器触发一种事件的方法，执行我们的代码。因此PULL更适合作为Android的解析。
借鉴与：http://blog.csdn.net/liuhe688/article/details/6415593
解析的XML为book.xml 放在assets:
<?xml version="1.0" encoding="utf-8"?>
<books>
<book>
<id>1001</id>
<name>Thinking In Java</name>
<price>80.00</price>
</book>
<book>
<id>1002</id>
<name>Core Java</name>
<price>90.00</price>
</book>
<book>
<id>1003</id>
<name>hello,Java</name>
<price>100.00</price>
</book>
</books>
保存XML信息的代码：
package com.example.xml01;
public class Book {
private int id;
private String name;
private float price;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
@Override
public String toString() {
return "Struct_Book [id=" + id + ", name=" + name + ", price=" + price + "]";
}
}
package com.example.xml01;
import java.io.InputStream;
import java.util.List;
public interface Bookparse {
public List<Book> parse(InputStream is) throws Exception;
public String serialize(List<Book> books) throws Exception;
}
第一个是使用SAX解析的方式：
package com.example.xml01;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
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;
import android.R.integer;
public class SaxBookParser implements Bookparse {
@Override
public List<Book> parse(InputStream is) throws Exception {
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser=factory.newSAXParser();
MyHandler handler= new MyHandler();
parser.parse(is, handler);
return handler.getBook();
}
@Override
public String serialize(List<Book> books) throws Exception {
// TODO Auto-generated method stub
return null;
}
private class MyHandler extends DefaultHandler{
private List<Book> books;
private Book book;
private StringBuilder builder;
public List<Book> getBook()
{
return books;
}
@Override
public void endDocument() throws SAXException {
// TODO Auto-generated method stub
super.endDocument();
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
// TODO Auto-generated method stub
super.endElement(uri, localName, qName);
if(localName.equals("id"))
{
book.setId(Integer.parseInt(builder.toString()));
}
else if(localName.equals("name"))
{
book.setName(builder.toString());
}
else if(localName.equals("price"))
{
book.setPrice(Float.parseFloat(builder.toString()));
}
else if(localName.equals("book"))
{
books.add(book);
}
}
@Override
public void startDocument() throws SAXException {
// TODO Auto-generated method stub
super.startDocument();
books= new ArrayList<Book>();
builder= new StringBuilder();
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes)
throws SAXException {
// TODO Auto-generated method stub
super.startElement(uri, localName, qName, attributes);
if(localName.equals("book"))
{
book= new Book();
}
builder.setLength(0);
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
// TODO Auto-generated method stub
super.characters(ch, start, length);
builder.append(ch, start, length); // 内部被清空 重新赋值
System.out.println(builder.toString());
//System.out.println(builder.length());
//System.out.println("ch: "+ch.toString());
}
}
}
对应的Activity代码：
package com.example.xml01;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
private Bookparse parser;
private List<Book> books;
private Button btn1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn1= (Button)findViewById(R.id.button1);
btn1.setOnClickListener(listener);
}
OnClickListener listener = new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
try {
InputStream is = getAssets().open("book.xml");
parser= new SaxBookParser();
books = parser.parse(is);
for(int i=0;i<books.size();i++)
{
System.out.println(books.toString());
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
}
第二个是PULL解析方式;
package com.example.xml02;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.xmlpull.v1.XmlPullParser;
import android.util.Xml;
public class PullBookParser implements Bookparse{
List<Book> books=null;
Book book=null;
@Override
public List<Book> parse(InputStream is) throws Exception {
XmlPullParser parser = Xml.newPullParser();
parser.setInput(is, "UTF-8");
int eventType = parser.getEventType();
while(eventType!=XmlPullParser.END_DOCUMENT)
{
switch (eventType) {
case XmlPullParser.START_DOCUMENT:
books= new ArrayList<Book>();
break;
case XmlPullParser.START_TAG:
if(parser.getName().equals("book"))
{
book= new Book();
}
else if(parser.getName().equals("id"))
{
eventType= parser.next();
book.setId(Integer.parseInt(parser.getText()));
}
else if(parser.getName().equals("name"))
{
eventType= parser.next();
book.setName(parser.getText());
}
else if(parser.getName().equals("price"))
{
eventType= parser.next();
book.setPrice(Float.parseFloat(parser.getText()));
}
break;
case XmlPullParser.END_TAG:
if(parser.getName().equals("book"))
{
books.add(book);
book=null;
}
default:
break;
}
eventType=parser.next();
}
return books;
}
@Override
public String serialize(List<Book> books) throws Exception {
// TODO Auto-generated method stub
return null;
}
}
对应的Activity；
package com.example.xml02;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.view.ActionMode;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
private Button button=null;
private List<Book> books;
private PullBookParser parser;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button=(Button)findViewById(R.id.button1);
button.setOnClickListener(listener);
}
OnClickListener listener = new OnClickListener() {
@Override
public void onClick(View v) {
try {
InputStream is = getAssets().open("book.xml");
parser = new PullBookParser();
books= parser.parse(is);
for(int i=0;i<books.size();i++)
{
System.out.println(books.toString());
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
}
第一个是使用SAX解析的方式：