import javax.xml.parsers.*;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import org.w3c.dom.*;
import java.io.*;
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;
 
public class parsetest {
 
    public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
        System.out.println("start xml parsing");
 
        parsetest test = new parsetest();
        String fileName = "test_file.xml";
        String tagFilter = "filter_tag";
 
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = null;
 
        File file = new File("c:\\javaprojects\\xml_parser\\test_file.xml");
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document document = db.parse(file);
        document.getDocumentElement().normalize();
 
        try {
            builder = factory.newDocumentBuilder();
            document = builder.parse(new File(fileName));
            test.filterElements(document, tagFilter);
            test.printNodeElements(document);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    // filter all elements whose tag name = filter_tag
    public void filterElements(Node parent, String filter) throws TransformerConfigurationException, TransformerException {
        NodeList children = parent.getChildNodes();
 
        for (int i = 0; i < children.getLength(); i++) {
            Node child = children.item(i);
 
            // only interested in elements
            if (child.getNodeType() == Node.ELEMENT_NODE) {
 
                // remove elements whose tag name  = filter
                // otherwise check its children for filtering with a recursive call
                if (child.getNodeName().equals(filter)) {
                    parent.removeChild(child);
                } else {
                    filterElements(child, filter);
                }
            }
        }
        Source source = new DOMSource(parent);
        File new_file = new File("c:\\javaprojects\\xml_parser\\new_test_file.xml");
        Result result = new StreamResult(new_file);
        // Write the DOM document to the file
        Transformer xformer = TransformerFactory.newInstance().newTransformer();
        xformer.transform(source, result);
    }
 
    // print a nodes elements and children
    public void printNodeElements(Node node) {
        System.out.println(node.getNodeName());
 
        NodeList children = node.getChildNodes();
 
        for (int i = 0; i < children.getLength(); i++) {
            Node child = children.item(i);
 
            if (child.getNodeType() == Node.ELEMENT_NODE) {
                printNodeElements(child);
            }
        }
    }
}