SAX解析：如何获取子节点 [英] SAX parsing: how to fetch child nodes
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问题描述
我使用SAX在android系统解析。对于下面的XML：
I'm using SAX parsing in android. For below XML:
<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<title>Game Analysis</title>
<item>
<title>GTA</title>
<description>ABC</description>
<pubDate>Sat, 21 Feb 2012 05:18:23 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3" length="6670315"/>
</item>
<item>
<title>CoD</title>
<description>XYZ</description>
<pubDate>Sat, 21 Feb 2011 05:18:23 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3" length="6670315"/>
</item>
</channel>
</rss>
我要取的第一次出现＆LT;标题方式＆gt; （略低于）
然后从每块我又需要提取＆LT;标题＆GT; ＆安培; ＆LT;外壳方式＆gt;
Then from every block I again need to extract <title> & <enclosure>.
我可以获取第一个＆LT;标题＆GT; 使用：
公共无效的startElement（URI字符串，字符串的localName，字符串QNAME，
属性属性）抛出的SAXException {
如果（用于QName.equals（标题））
...
}
I can fetch the first <title> using:
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
if (qName.equals("title"))
...
}
不过，我应该如何获取里面＆LT标签;项目＆GT;块？
But, how should I fetch the tags inside <item> block?
推荐答案
下面是如何我已经做了与SAX。
Here is how I've done that with SAX.
我修改了咬你的XML文件。
I have modified a bite your XML file.
的 XML文件的
<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<title>Game Analysis</title>
<item>
<title>GTA</title>
<description>ABC</description>
<pubDate>Sat, 21 Feb 2012 05:18:23 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3/1" length="6670315"/>
</item>
<item>
<title>CoD</title>
<description>XYZ</description>
<pubDate>Sat, 21 Feb 2011 05:45:10 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3/2" length="6670345"/>
</item>
<item>
<title>AtV</title>
<description>fgh</description>
<pubDate>Sat, 21 Feb 2011 06:20:10 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3/3" length="6670364"/>
</item>
</channel>
<channel>
<title>Game Analysis 2</title>
<item>
<title>GTA 2</title>
<description>ABC 2</description>
<pubDate>Sat, 21 Feb 2012 04:18:23 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3/2/1" length="6670315"/>
</item>
<item>
<title>CoD 2</title>
<description>XYZ 2</description>
<pubDate>Sat, 21 Feb 2011 04:45:10 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3/2/2" length="6670345"/>
</item>
<item>
<title>AtV 2</title>
<description>fgh</description>
<pubDate>Sat, 21 Feb 2011 05:20:10 GMT</pubDate>
<enclosure type="audio/mpeg" url="http://URL.mp3/2/3" length="6670364"/>
</item>
</channel>
</rss>
实体
的渠道的
public class Channel {
private String title;
private ArrayList<Item> alItems;
public Channel(){}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public ArrayList<Item> getAlItems() {
return alItems;
}
public void setAlItems(ArrayList<Item> alItems) {
this.alItems = alItems;
}
}
的机箱的
public class Enclosure {
private String type;
private URL url;
private Integer length;
public Enclosure(){}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public URL getUrl() {
return url;
}
public void setUrl(URL url) {
this.url = url;
}
public Integer getLength() {
return length;
}
public void setLength(Integer length) {
this.length = length;
}
}
的项目的
public class Item {
private String title;
private String description;
private String pubDate;
private Enclosure enclosure;
public Item(){}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getPubDate() {
return pubDate;
}
public void setPubDate(String pubDate) {
this.pubDate = pubDate;
}
public Enclosure getEnclosure() {
return enclosure;
}
public void setEnclosure(Enclosure enclosure) {
this.enclosure = enclosure;
}
}
处理程序
的的ChannelHandler 的
public class ChannelHandler extends DefaultHandler{
private ArrayList<Channel> alChannels;
private Channel channel;
private String reading;
private ArrayList<Item> alItems;
private Item item;
private Enclosure enclosure;
public ChannelHandler(){
super();
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
if(qName.equals("rss")){
alChannels = new ArrayList<>();
}
else if(qName.equals("channel")){
channel = new Channel();
}
else if(qName.equals("item")){
item = new Item();
}
else if(qName.equals("enclosure")){
enclosure = new Enclosure();
enclosure.setType(attributes.getValue("type"));
try {
enclosure.setUrl(new URL(attributes.getValue("url")));
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
enclosure.setLength(Integer.parseInt(attributes.getValue("length")));
}
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if(qName.equals("channel")){
channel.setAlItems(alItems);
alChannels.add(channel);
alItems = null;
}
if(qName.equals("title")){
if(alItems == null){
channel.setTitle(reading);
alItems = new ArrayList<>();
}
else if(item != null) {
item.setTitle(reading);
}
}
else if(qName.equals("item")){
if(alItems != null){
alItems.add(item);
item = null;
}
}
else if(qName.equals("description")){
item.setDescription(reading);
}
else if(qName.equals("pubDate")){
item.setPubDate(reading);
}
else if(qName.equals("enclosure")){
item.setEnclosure(enclosure);
}
}
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
reading = new String(ch, start, length);
}
public ArrayList<Channel> getAlChannels() {
return alChannels;
}
}
管理
的 XMLManager 的
public final class XMLManager {
public static ArrayList<Channel> getAlChannels(){
ArrayList<Channel> alChannels = null;
SAXParserFactory factory = SAXParserFactory.newInstance();
try {
SAXParser parser = factory.newSAXParser();
File file = new File("D:\\Loic_Workspace\\TestSAX2\\res\\test.xml");
ChannelHandler channelHandler = new ChannelHandler();
parser.parse(file, channelHandler);
alChannels = channelHandler.getAlChannels();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return alChannels;
}
}
主要
的 MyMain 的
public class MyMain {
/**
* @param args
*/
public static void main(String[] args) {
Enclosure enclosure = null;
for(Channel channel : XMLManager.getAlChannels()){
System.out.println("Channel title : "+channel.getTitle());
System.out.println("------------------------");
for(Item i:channel.getAlItems()){
System.out.println(i.getTitle());
System.out.println(i.getPubDate());
System.out.println("Enclosure : ");
enclosure = i.getEnclosure();
System.out.println(enclosure.getType());
System.out.println(enclosure.getUrl());
System.out.println(enclosure.getLength());
System.out.println("------------------------");
}
}
}
}
输出在控制台
Channel title : Game Analysis
------------------------
GTA
Sat, 21 Feb 2012 05:18:23 GMT
Enclosure :
audio/mpeg
http://URL.mp3/1
6670315
------------------------
CoD
Sat, 21 Feb 2011 05:45:10 GMT
Enclosure :
audio/mpeg
http://URL.mp3/2
6670345
------------------------
AtV
Sat, 21 Feb 2011 06:20:10 GMT
Enclosure :
audio/mpeg
http://URL.mp3/3
6670364
------------------------
Channel title : Game Analysis 2
------------------------
GTA 2
Sat, 21 Feb 2012 04:18:23 GMT
Enclosure :
audio/mpeg
http://URL.mp3/2/1
6670315
------------------------
CoD 2
Sat, 21 Feb 2011 04:45:10 GMT
Enclosure :
audio/mpeg
http://URL.mp3/2/2
6670345
------------------------
AtV 2
Sat, 21 Feb 2011 05:20:10 GMT
Enclosure :
audio/mpeg
http://URL.mp3/2/3
6670364
------------------------
所以，它的工作原理;）
So it works ;)
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