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() {

  /*
     * 创建文件工厂实例
     */
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    // 如果创建的解析器在解析XML文档时必须删除元素内容中的空格，则为true，否则为false
    dbf.setIgnoringElementContentWhitespace(true);

    try {
      /*
       * 创建文件对象
       */
      DocumentBuilder db = dbf.newDocumentBuilder();// 创建解析器，解析XML文档
      Document doc = db.parse(xmlPath); // 使用dom解析xml文件

      /*
       * 历遍列表，进行XML文件的数据提取
       */
      // 根据节点名称来获取所有相关的节点
      NodeList sonlist = doc.getElementsByTagName("son");
      for (int i = 0; i < sonlist.getLength(); i++) // 循环处理对象
      {
        // 节点属性的处理
        Element son = (Element) sonlist.item(i);
        // 循环节点son内的所有子节点
        for (Node node = son.getFirstChild(); node != null; node = node
            .getNextSibling()) {
          // 判断是否为元素节点
          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());
    }
  }

  // 修改
  public static void modifySon() {
    // 创建文件工厂实例
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setIgnoringElementContentWhitespace(true);
    try {
      // 从XML文档中获取DOM文档实例
      DocumentBuilder db = dbf.newDocumentBuilder();
      // 获取Document对象
      Document xmldoc = db.parse(xmlPath);

      // 获取根节点
      Element root = xmldoc.getDocumentElement();
      // 定位id为001的节点
      Element per = (Element) selectSingleNode("/father/son[@id='001']",
          root);
      // 将age节点的内容更改为28
      per.getElementsByTagName("age").item(0).setTextContent("28");
      // 保存
      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());
    }
  }

  // 获取目标节点，进行删除，最后保存
  public static void discardSon() {

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

    try {

      DocumentBuilder db = dbf.newDocumentBuilder();
      Document xmldoc = db.parse(xmlPath);
      // 获取根节点
      Element root = xmldoc.getDocumentElement();
      // 定位根节点中的id=002的节点
      Element son = (Element) selectSingleNode("/father/son[@id='002']",
          root);
      // 删除该节点
      root.removeChild(son);
      // 保存
      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());
    }
  }

  // 新增节点
  public static void createSon() {
    // 创建文件工厂实例
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setIgnoringElementContentWhitespace(false);

    try {

      DocumentBuilder db = dbf.newDocumentBuilder();
      // 创建Document对象
      Document xmldoc = db.parse(xmlPath);
      // 获取根节点
      Element root = xmldoc.getDocumentElement();
      // 创建节点son，设置对应的id为004
      Element son = xmldoc.createElement("son");
      son.setAttribute("id", "004");
      // 创建节点name
      Element name = xmldoc.createElement("name");
      name.setTextContent("小儿子");
      son.appendChild(name);
      // 创建节点age
      Element age = xmldoc.createElement("age");
      age.setTextContent("0");
      son.appendChild(age);
      // 把son添加到根节点中
      root.appendChild(son);
      // 保存
      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());
    }
  }

  // 修改节点信息
  public static Node selectSingleNode(String express, Element source) {
    Node result = null;
    //创建XPath工厂
    XPathFactory xpathFactory = XPathFactory.newInstance();
    //创建XPath对象
    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;
  }

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

    getFamilyMemebers();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    modifySon();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    System.out.println("修改数据");
    getFamilyMemebers();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    discardSon();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    System.out.println("删除数据");
    getFamilyMemebers();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    createSon();
    System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");
    System.out.println("添加数据");
    getFamilyMemebers();
  }
}

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

  
    老大
    20
  
  
    老二
    18
  
  
    老三
    13