Adding a Comment to a DOM Document
When creating a comment node, the string `--' must never appear
in the comment text. The default XML writers in J2SE 1.4 will output the
comment text with the `--' and therefore generate invalid XML.
This is the sample input for the example:
The resulting XML from running the example is:
// Obtain an XML document; this method is implemented in
// The Quintessential Program to Create a DOM Document from an XML File
Document doc = parseXmlFile("infilename.xml", false);
// Add a comment at the beginning of the document
Element element = doc.getDocumentElement();
Comment comment = doc.createComment("A Document Comment");
element.getParentNode().insertBefore(comment, element);
// Find all elements with the name "entry" and append a comment
NodeList list = doc.getElementsByTagName("entry");
for (int i=0; i<list.getLength(); i++) {
element = (Element)list.item(i);
comment = doc.createComment("index="+i);
// Add the comment after this element
element.getParentNode().insertBefore(comment, element.getNextSibling());
}
// "--" must never appear in the text used to create the comment
comment = doc.createComment("invalid -- comment");
boolean validComment = comment.getNodeValue().indexOf("--") < 0;
<?xml version="1.0" encoding="UTF-8"?>
<map>
<entry key="key1" value="value1" />
<entry key="key2" />
</map>
<?xml version="1.0" encoding="UTF-8"?>
<!--A Document Comment--><map>
<entry key="key1" value="value1"/><!--index=0-->
<entry key="key2"/><!--index=1-->
</map>
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