driverutilities2.java

本类库包含了常规的数据库联结操作

package coreservlets;

import java.io.*;
import java.util.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
import coreservlets.beans.*;

public class DriverUtilities2 extends DriverUtilities
{
	public static final String DEFAULT_FILE="drivers.xml";
	
	public static void loadDrivers()
	{
		DriverUtilities2.loadDrivers(DEFAULT_FILE);
	}
	
	public static void loadDrivers(String filename)
	{
		File file=new File(filename);
		try
		{
			InputStream in=new FileInputStream(file);
			DocumentBuilderFactory builderFactory=DocumentBuilderFactory.newInstance();
			DocumentBuilder builder=builderFactory.newDocumentBuilder();
			Document document=builder.parse(in);
			document.getDocumentElement().normalize();
			Element rootElement=document.getDocumentElement();
			NodeList driverElements=rootElement.getElementsByTagName("driver");
			for(int i=0;i<driverElements.getLength();i++)
			{
				Node node=driverElements.item(i);
				DriverInfoBean info=DriverUtilities2.createDriverInfoBean(node);
				if(info!=null)
				{
					addDriverInfoBean(info);
				}
			}
		}
		catch(FileNotFoundException fnfe)
		{
			System.err.println("Can't find"+filename);
		}
		catch(IOException ioe)
		{
			System.err.println("Problem reading file:"+ioe);
		}
		catch(ParserConfigurationException pce)
		{
			System.err.println("Can't create DocumentBuilder");
		}
		catch(SAXException se)
		{
			System.err.println("Problem parsing document:"+se);
		}
	}
	
	public static DriverInfoBean createDriverInfoBean(Node node)
	{
		Map map=new HashMap();
		NodeList children=node.getChildNodes();
		for(int i=0;i<children.getLength();i++)
		{
			Node child=children.item(i);
			String nodeName=child.getNodeName();
			if(child instanceof Element)
			{
				Node textNode=child.getChildNodes().item(0);
				if(textNode!=null)
				{
					map.put(nodeName,textNode.getNodeValue());
				}
			}
		}
		return(new DriverInfoBean((String)map.get("vendor"),(String)map.get("description"),(String)map.get("driver-class"),(String)map.get("url")));
	}
}