个人项目“RSS FEED”XML解析器
问题描述：
我对Java相对较新，我一直在试图弄清楚如何在几天的长时间内输出以下标记。我真的很感谢对这个问题的一些见解。看起来我所能找到的或尝试的所有东西都无法正确显示。 （请原谅，俗气的新闻文章）个人项目“RSS FEED”XML解析器
<item>
<pubDate>Sat, 21 Sep 2013 02:30:23 EDT</pubDate>
<title>
<![CDATA[
Carmen Bryan Lashes Out at Beyonce Fans for Throwing Shade (@carmenbryan)
]]>
</title>
<link>
http://www.vladtv.com/blog/174937/carmen-bryan-lashes-out-at-beyonce-fans-for-throwing-shade/
</link>
<guid>
http://www.vladtv.com/blog/174937/carmen-bryan-lashes-out-at-beyonce-fans-for-throwing-shade/
</guid>
<description>
<![CDATA[
<img ... /><br />.
<p>In response to someone who reminded Bryan that Jay Z has Beyonce now, she tweeted.</p>
<p>Check out what else Bryan had to say above.</p>
<p>Source: </p>
]]>
</description>
</item>
我已成功地解析XML并打印出标题和描述元素标签的内容，但输出为description元素标签还包括其所有子元素标记。我希望将来可以使用此项目来构建我的Java产品组合，请帮助！
我迄今为止代码：
public class NewXmlReader
{
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document docXml = builder.parse(NewXMLReaderHandlers.inputHandler());
docXml.getDocumentElement().normalize();
NewXMLReaderHandlers.handleItemTags(docXml, "item");
} catch (ParserConfigurationException | SAXException parserConfigurationException) {
System.out.println("You Are Not XML formated !!");
parserConfigurationException.printStackTrace();
} catch (IOException iOException) {
System.out.println("URL NOT FOUND");
iOException.getCause();
}
}
}
public class NewXMLReaderHandlers {
private static int ARTICLELENGTH;
public static String inputHandler() throws IOException {
InputStreamReader inputStream = new InputStreamReader(System.in);
BufferedReader bufferRead = new BufferedReader(inputStream);
System.out.println("Please Enter A Proper URL: ");
String urlPageString = bufferRead.readLine();
return urlPageString;
}
public static void handleItemTags(Document document, String rssFeedParentTopicTag){
NodeList listOfArticles = document.getElementsByTagName(rssFeedParentTopicTag);
NewXMLReaderHandlers.ARTICLELENGTH = listOfArticles.getLength();
String rootElement = document.getDocumentElement().getNodeName();
if (rootElement == "rss"){
System.out.println("We Have An RSS Feed To Parse");
for (int i = 0; i < NewXMLReaderHandlers.ARTICLELENGTH; i++) {
Node itemNode = (Node) listOfArticles.item(i);
if (itemNode.getNodeType() == Node.ELEMENT_NODE) {
Element itemElement= (Element) itemNode;
tagContent (itemElement, "title");
tagContent (itemElement, "description");
}
}
}
}
public static void tagContent (Element item, String tagName) {
NodeList tagNodeList = item.getElementsByTagName(tagName);
Element tagElement = (Element)tagNodeList.item(0);
NodeList tagTElist = tagElement.getChildNodes();
Node tagNode = tagTElist.item(0);
// System.out.println(" - " + tagName + " : " + tagNode.getNodeValue() + "\n");
if(tagName == "description"){
System.out.println(" - " + tagName + " : " + tagNode.getNodeValue() + "\n\n");
System.out.println(" Do We Have Any Siblings? " + tagNode.getNextSibling().getNodeValue() + "\n");
}
}
}
答
对于我的钱，最简单的解决办法是使用XPath API。
本质上，它是XML的查询语言。参见XPath Tutorial作为底漆。
此示例使用从SO RSS源，它采用<entry...>代替<item>，但我已经用于其他RSS（和XML）文件，甚至是非常复杂的HTML文档相同的技术......
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class TestRSSFeed {
public static void main(String[] args) {
try {
// Read the feed...
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
Document doc = factory.newDocumentBuilder().parse("http://*.com/feeds/tag?tagnames=java&sort=newest");
Element root = doc.getDocumentElement();
// Create a xPath instance
XPath xPath = XPathFactory.newInstance().newXPath();
// Find all the nodes that are named <entry...> any where in
// the document that live under the parent node...
XPathExpression expression = xPath.compile("//entry");
NodeList nl = (NodeList) expression.evaluate(root, XPathConstants.NODESET);
System.out.println("Found " + nl.getLength() + " items...");
for (int index = 0; index < nl.getLength(); index++) {
Node node = nl.item(index);
// This is a sub node search.
// The search is based on the parent node and looks for a single
// node titled "title" that belongs to the parent node...
// I did this because I'm only expecting a single node...
expression = xPath.compile("title");
Node child = (Node) expression.evaluate(node, XPathConstants.NODE);
System.out.println(child.getTextContent());
}
} catch (IOException | ParserConfigurationException | SAXException exp) {
exp.printStackTrace();
} catch (XPathExpressionException ex) {
ex.printStackTrace();
}
}
}
现在，你可以做一些非常复杂的查询，但我想我会用一个简单的例子开始;）
答
万一有人还在纳闷，我怎么设法解决CDATA之谜：
逻辑如下s：
一旦你得到程序提取所有xml以显示正确的节点树，就像rss提要显示的那样，如果任何xml数据被包装在CDATA标签中，唯一访问这些信息的方法是创建新的xml基于CDATA标签中的文本内容。解析新文档后，您应该能够访问所需的所有数据。
与使用常规DOM方法相比，它实现起来要容易得多。我尝试了几种组合，但我认为我遇到了一个新问题，或者我原本必须面对的实际问题。似乎问题是解析CDATA作为父节点的任何子元素。我似乎无法获得之后的任何信息，即
]]>似乎无法穿越。我试过解析子元素，但NodeList总是空着。还有什么建议？ – Khalismatic
没关系，我回答了我自己的问题！再次感谢MadProgrammer的帮助！ – Khalismatic
对不起，打算回到你身边，跟踪了一下：P – MadProgrammer