Cover Page by Gary Cornell, Cay S. Horstmann

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2.4. Locating Information with XPath

If you want to locate a specific piece of information in an XML document, it can be a bit of a hassle to navigate the nodes of the DOM tree. The XPath language makes it simple to access tree nodes. For example, suppose you have this XML document:

<configuration>    . . .    <database>       <username>dbuser</username>       <password>secret</password>       . . .    </database> </configuration>

You can get the database user name by evaluating the XPath expression

/configuration/database/username

That’s a lot simpler than the plain DOM approach:

1. Get the document node.

2. Enumerate its children.

3. Locate the database element.

4. Get its first child, the username element.

5. Get its first child, a text

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