请问哪位能给出Xalan应用XPath的代码例子?

Patrick_DK 2002-03-21 09:38:02
小弟正在做一个Application,有一部分的功能是操作几个用来存放数据信息的XML文档,包括,检索,增加,删除等等吧。如果纯粹用Java代码来遍历,效率当然太低了。
于是看了看Xalan的介绍,考虑使用XPath。不过没有找到相关的代码例子。不知道哪位高手能提供一个简短的Xalan应用XPath的代码例子给我瞧瞧。
另外,我想问问,是不是能够用JDOM配合XPath呢,还是一定要用DOM的?
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Patrick_DK 2002-03-21
to salute:

如果用光光用JDOM的话,你如何能够快速的操作的XML文档数据呢?
比如,迅速定位到某个节点等等。如果,每次执行对XML文档的操作,都要遍历一次整个XML文档,效率启不是太低了?

难道JDOM就不能和其他支持XPath的JavaAPI联合应用吗?
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salute 2002-03-21
"有一部分的功能是操作几个用来存放数据信息的XML文档,包括,检索,增加,删除等等吧"
用JDOM吧,正好适合做这个.

"于是看了看Xalan的介绍,考虑使用XPath。不过没有找到相关的代码例子。不知道哪位高手能提供一个简短的Xalan应用XPath的代码例子给我瞧瞧。"
XALAN是格式转换用,用到了XPATH的技术.和你的需求似乎不太相符.


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Patrick_DK 2002-03-21
to 楼上

偶想看看简单例子的原代码,不是看类库的原代码
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X25 2002-03-21
/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
// This file uses 4 space indents, no tabs.

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Properties;
import org.apache.xerces.parsers.DOMParser;
import org.apache.xpath.XPathAPI;
import org.apache.xml.utils.TreeWalker;
import org.apache.xml.utils.DOMBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.traversal.NodeIterator;
import org.xml.sax.SAXException;
import org.xml.sax.InputSource;

// Imported JAVA API for XML Parsing 1.0 classes
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

// Imported Serializer classes
import javax.xml.transform.*;
import javax.xml.transform.stream.*;
import javax.xml.transform.dom.*;

/**
* Very basic utility for applying an XPath epxression to an xml file and printing information
/ about the execution of the XPath object and the nodes it finds.
* Takes 2 arguments:
* (1) an xml filename
* (2) an XPath expression to apply to the file
* Examples:
* java ApplyXPath foo.xml /
* java ApplyXPath foo.xml /doc/name[1]/@last
* @see XPathAPI
*/
public class ApplyXPath
{
protected String filename = null;
protected String xpath = null;

/** Process input args and execute the XPath. */
public void doMain(String[] args)
throws Exception
{
filename = args[0];
xpath = args[1];

if ((filename != null) && (filename.length() > 0)
&& (xpath != null) && (xpath.length() > 0))
{
// Tell that we're loading classes and parsing, so the time it
// takes to do this doesn't get confused with the time to do
// the actual query and serialization.
System.out.println("Loading classes, parsing "+filename+", and setting up serializer");

// Set up a DOM tree to query.
InputSource in = new InputSource(new FileInputStream(filename));
DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance();
dfactory.setNamespaceAware(true);
Document doc = dfactory.newDocumentBuilder().parse(in);

// Set up an identity transformer to use as serializer.
Transformer serializer = TransformerFactory.newInstance().newTransformer();
serializer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");

// Use the simple XPath API to select a nodeIterator.
System.out.println("Querying DOM using "+xpath);
NodeIterator nl = XPathAPI.selectNodeIterator(doc, xpath);

// Serialize the found nodes to System.out.
System.out.println("<output>");

Node n;
while ((n = nl.nextNode())!= null)
{
if (isTextNode(n)) {
// DOM may have more than one node corresponding to a
// single XPath text node. Coalesce all contiguous text nodes
// at this level
StringBuffer sb = new StringBuffer(n.getNodeValue());
for (
Node nn = n.getNextSibling();
isTextNode(nn);
nn = nn.getNextSibling()
) {
sb.append(nn.getNodeValue());
}
System.out.print(sb);
}
else {
serializer.transform(new DOMSource(n), new StreamResult(System.out));
}
System.out.println();
}
System.out.println("</output>");
}
else
{
System.out.println("Bad input args: " + filename + ", " + xpath);
}
}

/** Decide if the node is text, and so must be handled specially */
static boolean isTextNode(Node n) {
if (n == null)
return false;
short nodeType = n.getNodeType();
return nodeType == Node.CDATA_SECTION_NODE || nodeType == Node.TEXT_NODE;
}

/** Main method to run from the command line. */
public static void main (String[] args)
throws Exception
{
if (args.length != 2)
{
System.out.println("java ApplyXPath filename.xml xpath\n"
+ "Reads filename.xml and applies the xpath; prints the nodelist found.");
return;
}

ApplyXPath app = new ApplyXPath();
app.doMain(args);
}

} // end of class ApplyXPath

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