Java Tutorial/XML/Comment
Содержание
Add a comment at the beginning of the document
<source lang="java">
import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.rument; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; public class Main {
public static void main(String[] argv) throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(true);
factory.setExpandEntityReferences(false);
Document doc = factory.newDocumentBuilder().parse(new File("filename"));
Element element = doc.getDocumentElement();
Comment comment = doc.createComment("A Document Comment");
element.getParentNode().insertBefore(comment, element);
}
}</source>
Find all elements with the name "entry" and append a comment
<source lang="java">
import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.rument; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.NodeList; public class Main {
public static void main(String[] argv) throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(true);
factory.setExpandEntityReferences(false);
Document doc = factory.newDocumentBuilder().parse(new File("filename"));
NodeList list = doc.getElementsByTagName("entry");
for (int i = 0; i < list.getLength(); i++) {
Element element = (Element) list.item(i);
Comment comment = doc.createComment("index=" + i);
element.getParentNode().insertBefore(comment, element.getNextSibling());
}
}
}</source>
Ignoring Comments While Parsing an XML File
<source lang="java">
import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Document; public class Main {
public static void main(String[] argv) throws Exception{
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setIgnoringComments(true);
Document doc = factory.newDocumentBuilder().parse(new File("infilename.xml"));
}
}</source>
Insert a comment in front of the element node
<source lang="java">
import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.rument; import org.w3c.dom.Document; import org.w3c.dom.Element; public class Main {
public static void main(String[] argv) throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(true);
factory.setExpandEntityReferences(false);
Document doc = factory.newDocumentBuilder().parse(new File("filename"));
Element element = doc.getElementById("key1");
element = doc.createElement("root");
doc.appendChild(element);
Comment comment = doc.createComment("a comment");
doc.insertBefore(comment, element);
}
}</source>
"--" must never appear in the text used to create the comment
<source lang="java">
import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.rument; import org.w3c.dom.Document; public class Main {
public static void main(String[] argv) throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setValidating(true);
factory.setExpandEntityReferences(false);
Document doc = factory.newDocumentBuilder().parse(new File("filename"));
Comment comment = doc.createComment("invalid -- comment");
boolean validComment = comment.getNodeValue().indexOf("--") < 0;
}
}</source>
