package Day01;
import java.io.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.*;
public class CRUDDEMO {
  /*public void addElement() throws Exception{
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.parse(new File ("src/Day01/Book.xml"));
    Element newEle = doc.createElement("作者");
    newEle.setTextContent("ZC");
    Node nod = doc.getElementsByTagName("書").item(0);
    nod.appendChild(newEle);
    Source sour = new DOMSource(doc);
    Result result = new StreamResult (new FileOutputStream("src/Day01/Book.xml"));
    write (sour, result);
  }*/
  public void addElement2() throws Exception{
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //建立工廠
    DocumentBuilder builder = factory.newDocumentBuilder(); //拿到builder
    Document doc = builder.parse(new File ("src/Day01/Book.xml")); //獲得document，這是終極目的
    Element newEle = doc.createElement("作者");// 創(chuàng)建新元素/標簽
    newEle.setTextContent("ZC"); //給元素設(shè)置內(nèi)容 <作者>ZC</作者>
    Node nod = doc.getElementsByTagName("書名").item(0); //通過nodelist的item()方法獲得具體節(jié)點
    /**
     * 在具體節(jié)點插入元素用 節(jié)點.insertBefore方法
     * 第一個參數(shù)是要插入的新節(jié)點，第二個是插入的位置
     */
    nod.insertBefore(newEle, doc.getElementsByTagName("書名").item(0));
    /**
     * DOMSource(Node n)
     * 注意 element是Node的一個子類，所以可以把doc放入構(gòu)造函數(shù)
     *
     *
     */
    Source sour = new DOMSource(doc);
    Result result = new StreamResult (new FileOutputStream("src/Day01/Book.xml"));
    write (sour, result);
  }
  public void write(Source source,Result result) {
    TransformerFactory tffactory = TransformerFactory.newInstance();
    Transformer tr;
    try {
      tr = tffactory.newTransformer();
      tr.transform(source, result);
    } catch (TransformerConfigurationException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (TransformerException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  public static void main(String[] args) throws Exception {
    CRUDDEMO cr = new CRUDDEMO();
    cr.addElement2();
  }
}

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<書架>
  <書>
    <書名>Thinking in Java</書名>
    <作者>Eric</作者>
    <售價>$34</售價>
  </書>
</書架>

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<書架>
  <書>
    <作者>ZC</作者>
    <書名>Thinking in Java</書名>
    <作者>Eric</作者>
    <售價>$34</售價>
  </書>
</書架>