java read xml

package com.solq.test;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class ToolXML {

    public static Map<String,Document> cacheXML= new HashMap<String,Document>();

    public static Document getXMLDom(String xml)

    {

        if(cacheXML.containsKey(xml)) return cacheXML.get(xml);

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

        DocumentBuilder builder = null;

        Document doc = null;

        File file = new File(xml);

        try {

            builder = factory.newDocumentBuilder();

            doc=builder.parse(file);

        } catch (ParserConfigurationException e) {

            e.printStackTrace();

        } catch (SAXException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        cacheXML.put(xml, doc);

        return doc;

    }



    public static NodeList getXmlNodeList(String xml,String attr,String v)

    {

        Document doc=getXMLDom(xml);

        XPathFactory xPathfactory = XPathFactory.newInstance();

        XPath xpath = xPathfactory.newXPath();

        javax.xml.xpath.XPathExpression expr = null;

        NodeList  ar = null;

        try {

            expr = xpath.compile("//datas/data[@"+attr+"='"+v+"']");

            ar = (NodeList)expr.evaluate(doc, XPathConstants.NODESET);

        } catch (XPathExpressionException e) {

            e.printStackTrace();

        }

        return ar;

    }

    public static void main(String[] args)

    {

        

        NodeList  nodes =getXmlNodeList("skill.xml","skillType","1");

        NodeList  nodes1 =getXmlNodeList("skill.xml","skillType","1");

         for (int i = 0; i < nodes.getLength(); i++) {

             Element el = (Element) nodes.item(i);

              System.out.println(el.getAttribute("skillName")); 

          }



    }

}

package com.solq.tool;



import java.io.File;



class XmlDomFileInfo{

    public long lastModified=0;

    public Document dom;

}

public class XMLHelper {

    private static Map<String,XmlDomFileInfo> cacheXML= new HashMap<String,XmlDomFileInfo>();

    private static int updateTime=24*60*60*1000;

    public static Document getXMLDom(String xml)

    {

        //Long lastModified = file.lastModified();

        //cache

        if(cacheXML.containsKey(xml)){

        

            if(cacheXML.get(xml).lastModified+updateTime>new Date().getTime())

            //if(cacheXML.get(xml).lastModified==lastModified) // new Date().getTime()+updateTime

            {

                //System.out.println("load cache xml");

                //System.out.println("return lastModified: "+cacheXML.get(xml).lastModified+" new Date().getTime()+updateTime :"+lastModified);

                return cacheXML.get(xml).dom;

            }

        }

        //System.out.println("one load");

        //no cache reRead xml

        File file = new File("xml/"+xml);

        Document doc = null;

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

        DocumentBuilder builder = null;



        try {

            builder = factory.newDocumentBuilder();

            doc=builder.parse(file);

        } catch (ParserConfigurationException e) {

            e.printStackTrace();

        } catch (SAXException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

        

        XmlDomFileInfo info=new XmlDomFileInfo();

        info.dom=doc;

        info.lastModified=new Date().getTime();



        cacheXML.put(xml, info);

        return doc;

    }



    public static NodeList getXmlNodeList(String xml,String attr,String id)

    {

        Document doc=getXMLDom(xml);

        XPathFactory xPathfactory = XPathFactory.newInstance();

        XPath xpath = xPathfactory.newXPath();

        //javax.xml.xpath.XPathExpression expr = null;

        NodeList  ar =null;

        try {

            //expr = xpath.compile("//datas/data[@"+attr+"='"+v+"']");

            ar = (NodeList)xpath.evaluate("//datas/data[@"+id+"='"+attr+"']",doc, XPathConstants.NODESET);

        } catch (XPathExpressionException e) {

            e.printStackTrace();

        }

        return ar;

    }

    public static Element getXmlElement(String xml,String attr,String id)

    {

        Document doc=getXMLDom(xml);

        XPathFactory xPathfactory = XPathFactory.newInstance();

        XPath xpath = xPathfactory.newXPath();

        Element  el =null;

        try {

            el=(Element)xpath.evaluate("//datas/data[@"+id+"='"+attr+"']",  doc, XPathConstants.NODE);

        } catch (XPathExpressionException e) {

            e.printStackTrace();

        }

        return el;

    }

    public static String getXmlAttr(String xml,String rv,String attr,String id)

    {

        Element el=getXmlElement(xml,attr,id);

        if(el==null) return "";

        return el.getAttribute(rv);

        

    }

    public static void test()

    {

        NodeList nodes =getXmlNodeList("skill.xml","1","skillType");

        if(nodes!=null)

         for (int i = 0; i < nodes.getLength(); i++) {

             Element el = (Element) nodes.item(i);

             System.out.println(el.getAttribute("skillName")); 

         }

        

        Element el =getXmlElement("skill.xml","2","skillType");

        

        if(el!=null)

            System.out.println(el.getAttribute("skillName")); 



    }

    public static void main(String[] args)

    {

        test();

    }

}

 

//加了文件修改时间判断