14.4. Manipulating an XML Document
Problem
You want to represent an XML document as a C++ object so that you can manipulate its elements, attributes, text, DTD, processing instructions, and comments.
Solution
Use Xerces’s implementation of the W3C DOM. First, use the class xercesc::DOMImplementationRegistry
to obtain an instance of
xercesc::DOMImplementation
, then use the DOMImplementation
to create an instance of the parser xercesc::DOMBuilder
. Next, register an instance of xercesc::DOMErrorHandler
to receive notifications of parsing
errors, and invoke the parser’s parseURI()
method with
your XML document’s URI or file pathname as its argument. If the parse is successful,
parseURI
will return a pointer to a DOMDocument
representing the XML document. You can then use
the functions defined by the W3C DOM specification to inspect and manipulate the
document.
When you are done manipulating the document, you can save it to a file by obtaining a
DOMWriter
from the DOMImplementation
and calling its writeNode()
method with a pointer to the DOMDocument
as its argument.
Example 14-10 shows how to use DOM to parse the document animals.xml from Example 14-1, locate and remove the node corresponding to Herby the elephant, and save the modified document.
Example 14-10. Using DOM to load, modify, and then save an XML document
#include <exception> #include <iostream> // cout #include <xercesc/dom/DOM.hpp> #include <xercesc/framework/LocalFileFormatTarget.hpp> #include <xercesc/sax/SAXException.hpp> ...
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