DOM模型的XML文件生成读取

import  org.w3c.dom.Document;
import  org.w3c.dom.Element;
import  org.w3c.dom.Text;
import  org.w3c.dom.Node;
import  org.w3c.dom.NodeList;
import  org.w3c.dom.NamedNodeMap;
import  org.w3c.dom.Attr;

import  javax.xml.parsers.DocumentBuilderFactory;
import  javax.xml.parsers.DocumentBuilder;

import  javax.xml.transform.Transformer;
import  javax.xml.transform.TransformerFactory;
import  javax.xml.transform.OutputKeys;

import  javax.xml.transform.dom.DOMSource;
import  javax.xml.transform.stream.StreamResult;

import  java.util.Properties;
import  java.io.FileOutputStream;
import  java.io.File;


public  class  WriteRead  ... {
    public WriteRead() ...{
    }

    String FILE_NAME = "my.xml";

    public void CreateXMLFile() throws Exception ...{
        //生成Document
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder dbr = dbf.newDocumentBuilder();
        Document doc = dbr.newDocument();

        //添加内容
        //根节点：
        Element root = doc.createElement("Root");
        root.setAttribute("att1", "Hello");
        root.setAttribute("att2", "World");

        Text rootText = doc.createTextNode("RootDate");

        root.appendChild(rootText);

        doc.appendChild(root);

        //子节点：
        Element child = doc.createElement("Child");
        child.setAttribute("att1", "Hello");
        child.setAttribute("att2", "Earth");

        Text childText = doc.createTextNode("ChildDate");

        child.appendChild(childText);

        root.appendChild(child);

        //孙子节点：
        Element grandchild = doc.createElement("GrandChild");
        grandchild.setAttribute("att1", "Hello");
        grandchild.setAttribute("att2", "Lover");

        Text grandchildText = doc.createTextNode("GrandChildDate");

        grandchild.appendChild(grandchildText);

        child.appendChild(grandchild);

        //生成文件
        TransformerFactory tff = TransformerFactory.newInstance();
        Transformer tfr = tff.newTransformer();
        Properties pts = tfr.getOutputProperties();
        pts.setProperty(OutputKeys.ENCODING, "GBK");
        tfr.setOutputProperties(pts);
        tfr.transform(new DOMSource(doc),
                      new StreamResult(new FileOutputStream(FILE_NAME, false)));
    }

    public void ReadXMLFile() throws Exception ...{
        //读取XML文件
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder dbr = dbf.newDocumentBuilder();
        File file = new File(FILE_NAME);
        Document doc = dbr.parse(file);

        Element root = doc.getDocumentElement();

        //顺序读取所有节点及属性
        System.out.println("The root element is:" + root.getNodeName());

        NodeList children = root.getChildNodes();
        System.out.println("There are " + children.getLength() +
                           " nodes in this document.");
        
        System.out.println("**********");
        for (Node child = root.getFirstChild(); child != null;
                          child = child.getNextSibling()) ...{
            System.out.println(child.getNodeName() + " = " +
                               child.getNodeValue());
        }

        System.out.println("**********");
        StepThrough(root);
        
        System.out.println("**********");
        StepThroughAll(root);

        //读取指定节点的值
        System.out.println("**********");        
        NodeList nl = root.getElementsByTagName("GrandChild");        
        System.out.println(nl.item(0).getFirstChild().getNodeValue());

        //读取指定节点的属性值
        System.out.println("**********");
        NodeList n2 = root.getElementsByTagName("Child");
        Element el2 = (Element)n2.item(0);
        Attr attr = el2.getAttributeNode("att2");        
        System.out.println(attr.getValue());
    }
    
    private void StepThrough(Node start) ...{
        System.out.println(start.getNodeName() + " = " + start.getNodeValue());
        for (Node child = start.getFirstChild(); child != null;
                          child = child.getNextSibling()) ...{
            StepThrough(child);
        }
    }

    private void StepThroughAll(Node start) ...{
        System.out.println(start.getNodeName() + " = " + start.getNodeValue());
        if (start.getNodeType() == Node.ELEMENT_NODE) ...{
            NamedNodeMap startAtt = start.getAttributes();
            for (int i = 0, len = startAtt.getLength(); i < len; i++) ...{
                Node attr = startAtt.item(i);
                System.out.println(" Attribute: " + attr.getNodeName() + " = " +
                                   attr.getNodeValue());
            }
        }
        for (Node child = start.getFirstChild(); child != null;
                          child = child.getNextSibling()) ...{
            StepThroughAll(child);
        }
    }


    public static void main(String[] args) ...{
        WriteRead writeread = new WriteRead();

        try ...{
            writeread.CreateXMLFile();
        } catch (Exception e) ...{
            e.printStackTrace();
        }
        try ...{
            writeread.ReadXMLFile();
        } catch (Exception e) ...{
            e.printStackTrace();
        }

    }
}   运行结果：
生成文件： <?xml version="1.0" encoding="GBK"?><Root att1="Hello" att2="World">RootDate<Child att1="Hello" att2="Earth">ChildDate<GrandChild att1="Hello" att2="Lover">GrandChildDate</GrandChild></Child></Root>
打印结果：
The root element is:Root
There are 2 nodes in this document.
**********
#text = RootDate
Child = null
**********
Root = null
#text = RootDate
Child = null
#text = ChildDate
GrandChild = null
#text = GrandChildDate
**********
Root = null
 Attribute: att1 = Hello
 Attribute: att2 = World
#text = RootDate
Child = null
 Attribute: att1 = Hello
 Attribute: att2 = Earth
#text = ChildDate
GrandChild = null
 Attribute: att1 = Hello
 Attribute: att2 = Lover
#text = GrandChildDate
**********
GrandChildDate
**********
Earth DOM模型：
org.w3c.dom

• interface org.w3c.dom.DOMImplementation
• interface org.w3c.dom.NamedNodeMap
• interface org.w3c.dom.Node
  • interface org.w3c.dom.Attr
  • interface org.w3c.dom.CharacterData

• interface org.w3c.dom.Comment
• interface org.w3c.dom.Text

• interface org.w3c.dom.CDATASection
• interface org.w3c.dom.Document
• interface org.w3c.dom.DocumentFragment
• interface org.w3c.dom.DocumentType
• interface org.w3c.dom.Element
• interface org.w3c.dom.Entity
• interface org.w3c.dom.EntityReference
• interface org.w3c.dom.Notation
• interface org.w3c.dom.ProcessingInstruction
• interface org.w3c.dom.NodeList

读取，生成XML文件，用到javax.xml的一些东西。v