Reading Database Properties from XML
		In an earlier class we used a JavaBean to connect to a database.  We provided the driver name and database URL via setter methods.  But that's essentially hardcoding these parameters.  Instead we should read them from an XML file so that we don't have to recompile just to change databases! So, let's plan the switch to XML. First, we'll need a simple XML file.  Start with the header. We'll implement the document type declaration later.  Since that's optional, we won't worry about it now. Then, we'll make a root element, say <database>.  This will have two child elements. <drivername>, for the driver name, and <databasURL>, for the database URL. At this point, no attribtues. On the bean, we'll simply implement the logic described in the previous slides to read this file and save the properties. There are a lot of moving parts here.  So let's test it by putting all of the logic in a separate class.  Once we're comfortable it is working, we'll move it into our JavaBean. Deployment Notes: The first time I tried this, NetBeans gave me an error stating that it could not find the org.w3c.dom package or the javax.xml.parsers package.  I downloaded the Java Web Services Developer Pack and got the necessary XML jars from there.  I copied these jars to the lib directory of both my JDK and Netbeans, but curiously, this did not work.  So I mounted the jars in my project, and it compiled. A strange one.  The book mentions method getRootElement of class Document that returns a single Element.  Well, they are far from right, but almost right at the same time.  It ends up that interface javax.swing.text.Document has a method called getRootElements that returns an array, but this isn't the same interface we want.  This document is used in Swing text components.  The one we want is org.w3c.dom.Document, which has a method called getDocumentElement.  That's what we want.  This one had me going in circles for a while! Example