XML解析之三：DOM

这个是最原始，最古老的方法。仅适用于配置文件解析，数据文件就别用它了。受不了的。
import java.io.File;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
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.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;

public class DOMTest {
    private static String inFile = "c:\\people.xml";

    private String outFile = "c:\\people.xml";

    public static void main(String args[]) {
        System.out.println("**********Start****************");
        DOMTest domTest = new DOMTest();
        //domTest.createDOM();
        domTest.readDom(inFile);
        System.out.println("**********End****************");
    }

    public void createDOM() {
        try {
            DocumentBuilder builder = DocumentBuilderFactory.newInstance()
                    .newDocumentBuilder();
            Document doc = builder.newDocument();
            Element root = doc.createElement("teacheer");
            Element wang = doc.createElement("wang");
            Element liu = doc.createElement("liu");
            wang.appendChild(doc.createTextNode("This is teacher wang"));
            liu.appendChild(doc.createTextNode("This is teacher liu"));
            root.appendChild(wang);
            doc.appendChild(root);
            Transformer transformer = TransformerFactory.newInstance().newTransformer();
            transformer.setOutputProperty(OutputKeys.ENCODING, "gb2312");
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            transformer.transform(new DOMSource(doc), new StreamResult(outFile));
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
   
    public void readDom(String filename) {
        try {
            DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            Document doc = builder.parse(new File(filename));
            System.out.println(doc.getDocumentURI());
           
            Element element = doc.getDocumentElement();
            String rootTagName = element.getNodeName();
            System.out.println("rootNODE:" + rootTagName);
            NodeList nodeList = element.getChildNodes();
            List aa = getTagInfo(nodeList);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
   
    private List getTagInfo(NodeList nodeList){
        List tagInfo = new ArrayList();
       
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node node = nodeList.item(i);
            if (node instanceof Text) {
                String value = node.getNodeValue();
                if (value != null && !value.trim().equals("")) {
                    System.out.println("text:" + value);
                }
            }
            if (node instanceof Element) {
                if (node.getAttributes() != null && node.getAttributes().equals("")){
                    Element element = (Element)node;
                    System.out.println("tag:" + node.getNodeName() + "   attr:" + element.getAttribute("id"));
                } else {
                    System.out.println("tag:" + node.getNodeName());
                }
            }
            tagInfo.add(node.getNodeName());
            tagInfo.add(node.getNodeValue());
            NodeList nodeChdList = node.getChildNodes();
            tagInfo = getTagInfo(nodeChdList);
        }
        return tagInfo;
    }
}


读取文件：



    wang
    20


    liu
    30


    zhang
    28