java uses DOM to add delete change and look up XML documents

This paper mainly studies java using DOM to add, delete, modify and check XML documents related codes, specific examples are shown as follows.

The source code:

package com.zc.homeWork18;

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class XMLWriter {

  private static String xmlPath = "src\\com\\zc\\homeWork18\\MyXml.xml";

  public static void getFamilyMemebers() {

  /*
     *  Create a file factory instance 
     */
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    //  If you create a parser that is parsing XML The whitespace in the element content must be removed when the document is written true , or for false
    dbf.setIgnoringElementContentWhitespace(true);

    try {
      /*
       *  Creating a file object 
       */
      DocumentBuilder db = dbf.newDocumentBuilder();//  Create a parser and parse XML The document 
      Document doc = db.parse(xmlPath); //  use dom parsing xml file 

      /*
       *  Go through the list XML Data extraction of files 
       */
      //  Retrieves all related nodes by node name 
      NodeList sonlist = doc.getElementsByTagName("son");
      for (int i = 0; i < sonlist.getLength(); i++) //  Loop processing object 
      {
        //  Processing of node attributes 
        Element son = (Element) sonlist.item(i);
        //  Loop nodes son All child nodes in 
        for (Node node = son.getFirstChild(); node != null; node = node
            .getNextSibling()) {
          //  Determine if it is an element node 
          if (node.getNodeType() == Node.ELEMENT_NODE) {
            String name = node.getNodeName();
            String value = node.getFirstChild().getNodeValue();
            System.out.println(name + " : " + value);
          }
        }
      }
    } catch (Exception e) {
      System.out.println(e.getMessage());
    }
  }

  //  Modify the 
  public static void modifySon() {
    //  Create a file factory instance 
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setIgnoringElementContentWhitespace(true);
    try {
      //  from XML Fetch in document DOM Document instance 
      DocumentBuilder db = dbf.newDocumentBuilder();
      //  To obtain Document object 
      Document xmldoc = db.parse(xmlPath);

      //  Get the root node 
      Element root = xmldoc.getDocumentElement();
      //  positioning id for 001 The nodes of the 
      Element per = (Element) selectSingleNode("/father/son[@id='001']",
          root);
      //  will age Change the content of the node to 28
      per.getElementsByTagName("age").item(0).setTextContent("28");
      //  save 
      TransformerFactory factory = TransformerFactory.newInstance();
      Transformer former = factory.newTransformer();
      former.transform(new DOMSource(xmldoc), new StreamResult(new File(
          xmlPath)));
    } catch (Exception e) {
      System.out.println(e.getMessage());
    }
  }

  //  Get the target node, delete it, and finally save it 
  public static void discardSon() {

    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setIgnoringElementContentWhitespace(true);

    try {

      DocumentBuilder db = dbf.newDocumentBuilder();
      Document xmldoc = db.parse(xmlPath);
      //  Get the root node 
      Element root = xmldoc.getDocumentElement();
      //  Locates in the root node id=002 The nodes of the 
      Element son = (Element) selectSingleNode("/father/son[@id='002']",
          root);
      //  Delete the node 
      root.removeChild(son);
      //  save 
      TransformerFactory factory = TransformerFactory.newInstance();
      Transformer former = factory.newTransformer();
      former.transform(new DOMSource(xmldoc), new StreamResult(new File(
          xmlPath)));

    } catch (Exception e) {
      System.out.println(e.getMessage());
    }
  }

  //  The new node 
  public static void createSon() {
    //  Create a file factory instance 
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setIgnoringElementContentWhitespace(false);

    try {

      DocumentBuilder db = dbf.newDocumentBuilder();
      //  create Document object 
      Document xmldoc = db.parse(xmlPath);
      //  Get the root node 
      Element root = xmldoc.getDocumentElement();
      //  Create a node son , set the corresponding id for 004
      Element son = xmldoc.createElement("son");
      son.setAttribute("id", "004");
      //  Create a node name
      Element name = xmldoc.createElement("name");
      name.setTextContent(" The younger son ");
      son.appendChild(name);
      //  Create a node age
      Element age = xmldoc.createElement("age");
      age.setTextContent("0");
      son.appendChild(age);
      //  the son Add to the root node 
      root.appendChild(son);
      //  save 
      TransformerFactory factory = TransformerFactory.newInstance();
      Transformer former = factory.newTransformer();
      former.transform(new DOMSource(xmldoc), new StreamResult(new File(
          xmlPath)));

    } catch (Exception e) {
      System.out.println(e.getMessage());
    }
  }

  //  Modify node information 
  public static Node selectSingleNode(String express, Element source) {
    Node result = null;
    // create XPath The factory 
    XPathFactory xpathFactory = XPathFactory.newInstance();
    // create XPath object 
    XPath xpath = xpathFactory.newXPath();
    try {
      result = (Node) xpath.evaluate(express, source, XPathConstants.NODE);
      System.out.println(result);
    } catch (XPathExpressionException e) {
      System.out.println(e.getMessage());
    }

    return result;
  }

  //  print 
  public static void main(String[] args) {

    getFamilyMemebers();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    modifySon();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    System.out.println(" Modify the data ");
    getFamilyMemebers();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    discardSon();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    System.out.println(" Delete the data ");
    getFamilyMemebers();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    createSon();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    System.out.println(" Add data ");
    getFamilyMemebers();
  }
}

XML file

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<father>
  <son id="001">
    <name> The eldest brother </name>
    <age>20</age>
  </son>
  <son id="002">
    <name> The old 2</name>
    <age>18</age>
  </son>
  <son id="003">
    <name> The old 3</name>
    <age>13</age>
  </son>

</father>

conclusion

The above is this article about java using DOM to add, delete, modify and check XML documents all the content of the operation example code, I hope to help you. Interested friends can continue to refer to the site of other related topics, if there are shortcomings, welcome to leave a message to point out. Thank you for your support!