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我有这样的代码来解析XML数据..解析XML全光照SAX在Java中
但当起始元素和endElement函数被调用，他们没有得到的参数值（如名称参数没有任何数据）当打结时打印参数值。它没有任何价值，为什么？
我打电话updateArticle功能在下面的代码
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
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.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
public class RSSHandler extends DefaultHandler {
// Used to define what elements we are currently in
private boolean inItem = false;
private boolean inTitle = false;
private boolean inLink = false;
// Feed and Article objects to use for temporary storage
private Article currentArticle = new Article();
private Feed currentFeed = new Feed();
// Number of articles added so far
private int articlesAdded = 0;
private ArrayList<Article> articles = new ArrayList<Article>();
private ArrayList<Feed> feeds = new ArrayList<Feed>();
// Number of articles to download
private static final int ARTICLES_LIMIT = 15;
// The possible values for targetFlag
private static final int TARGET_FEED = 0;
private static final int TARGET_ARTICLES = 1;
// A flag to know if looking for Articles or Feed name
private int targetFlag;
public RSSHandler(){ }
public void startElement(String uri, String name, String qName,Attributes atts) {
if (name.trim().equals("title"))
inTitle = true;
else if (name.trim().equals("item"))
inItem = true;
else if (name.trim().equals("link"))
inLink = true;
System.out.println(name.trim());
}
public void endElement(String uri, String name, String qName)throws SAXException {
if (name.trim().equals("title"))
inTitle = false;
else if (name.trim().equals("item"))
inItem = false;
else if (name.trim().equals("link"))
inLink = false;
// Check if looking for feed, and if feed is complete
if (targetFlag == TARGET_FEED && currentFeed.url != null && currentFeed.title != null) {
// We know everything we need to know, so insert feed and exit
System.out.println("add current feed");
feeds.add(currentFeed);
// throw new SAXException();
}
// Check if looking for article, and if article is complete
if (targetFlag == TARGET_ARTICLES && currentArticle.url != null && currentArticle.title != null) {
Article article = new Article();
article.feedId = currentFeed.id;
article.title = currentArticle.title;
article.url = currentArticle.url;
System.out.print(article.title);
articles.add(article);
//store articles in database
currentArticle.title = null;
currentArticle.url = null;
// Lets check if we've hit our limit on number of articles
articlesAdded++;
if (articlesAdded >= ARTICLES_LIMIT)
throw new SAXException();
}
}
public ArrayList<Article> getArticles(){
return this.articles;
}
public ArrayList<Feed> getFeeds(){
return this.feeds;
}
public void characters(char ch[], int start, int length) {
String chars = (new String(ch).substring(start, start + length));
System.out.println(chars);
try {
// If not in item, then title/link refers to feed
if (!inItem) {
if (inTitle)
currentFeed.title = chars;
} else {
if (inLink)
currentArticle.url = new URL(chars);
if (inTitle)
currentArticle.title = chars;
}
} catch (MalformedURLException e) {
}
}
public void createFeed(URL url) {
try {
targetFlag = TARGET_FEED;
currentFeed.url = url;
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
xr.setContentHandler(this);
xr.parse(new InputSource(url.openStream()));
} catch (IOException e) {}
catch (SAXException e) {}
catch (ParserConfigurationException e) {}
}
public void updateArticles(Feed feed) {
try {
targetFlag = TARGET_ARTICLES;
currentFeed = feed;
System.out.println(feed.url.toString());
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
xr.setContentHandler(this);
xr.parse(new InputSource(currentFeed.url.openStream()));
} catch (IOException e) {}
catch (SAXException e) {}
catch (ParserConfigurationException e) {}
}
}
@adham如果localName或qName都是空的，那么有可能是错误的。 –