java解析XML的三种方法

1.SAX事件解析

package com.wzh.sax;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

//
public class Saxhandler extends DefaultHandler {

	@Override
	public void startDocument() throws SAXException {
		System.out.println("开始解析XML文档...");
	}

	@Override
	public void endDocument() throws SAXException {
		System.out.println("结束解析XML文档...");
	}

	@Override
	public void startElement(String uri, String localName, String qName,
			Attributes attributes) throws SAXException {
		// TODO Auto-generated method stub
		super.startElement(uri, localName, qName, attributes);
		System.out.println("开始解析节点["+qName+"]...");
		System.out.println("共有["+attributes.getLength()+"]个属性");
	}

	@Override
	public void characters(char[] ch, int start, int length)
			throws SAXException {
		// TODO Auto-generated method stub
		super.characters(ch, start, length);
		String content =new String(ch,start,length);
		System.out.println(content);
	}

	@Override
	public void endElement(String uri, String localName, String qName)
			throws SAXException {
		// TODO Auto-generated method stub
		super.endElement(uri, localName, qName);
		System.out.println("结束解析XML节点...");
	}
}

　　

2.Dom加载解析

package com.wzh.dom;

import java.util.Iterator;

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

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

public class DomHandler {

	/*
	 * 解析XML
	 */
	public void read(String fileName) throws Exception {
		// 定义工厂API 使应用程序能够从XML文档获取生成DOM对象树的解析器
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		// 获取此类的实例之后，将可以从各种输入源解析XML
		DocumentBuilder builder = factory.newDocumentBuilder();
		// builder.parse(this.getClass().getResourceAsStream("/" + fileName));
		// Document接口表示整个HTML或XML文档，从概念上讲，它是文档树的根，并提供对文档数据的基本访问
		Document document = builder.parse(this.getClass().getResourceAsStream(
				"/" + fileName));
		// 获取根节点
		Element root = document.getDocumentElement();
		System.out.println(root.getNodeName());

		//读取database节点NodeList接口提供对节点的有序集合的抽象
		NodeList nodeList = root.getElementsByTagName("database");
		for (int i = 0; i < nodeList.getLength(); i++) {
			// 获取一个节点
			Node node = nodeList.item(i);
			// 获取该节点所有属性
			NamedNodeMap attributes = node.getAttributes();
			for (int j = 0; j < attributes.getLength(); j++) {
				Node attribute = attributes.item(j);
				System.out.println(attribute.getNodeName() + ":"
						+ attribute.getNodeValue());
			}
			//获取所有子节点数据
			NodeList childNodes=node.getChildNodes();
			for (int j = 0; j < childNodes.getLength(); j++) {
				Node childNode=childNodes.item(j);
				System.out.println(childNode.getNodeName()+":"+childNode.getNodeValue());
			}
		}
	}

	public static void main(String[] args) throws Exception {
		new DomHandler().read("data-source.xml");

	}
}

　　

3.dom4j解析

package com.wzh.dom4j;

import java.io.FileOutputStream;
import java.sql.DatabaseMetaData;
import java.util.Iterator;
import java.util.List;

import org.dom4j.*;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

public class Dom4jHandler {

public void add() throws Exception {
// 1.创建一个Document
Document document = DocumentHelper.createDocument();
// 2.给Document添加数据
Element root = document.addElement("DataSource");
// 添加注释
root.addComment("这是注释信息");
// 在root根节点下面添加一个子节点
Element database = root.addElement("database");
database.addAttribute("name", "mysql");
database.addAttribute("version", "5.0");
// 添加子节点
database.addElement("driver").setText("com.mysql.jdbc.Driver");
database.addElement("url")
.setText("jdbc:mysql://localhost:3306/myjdbc");
database.addElement("user").setText("root");
database.addElement("password").setText("root");
// 3.将Document写出文件
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("utf-8");
// FileOutputStream默认生成的路径在根路径
XMLWriter xw = new XMLWriter(new FileOutputStream("db.xml"), format);
xw.write(document);
xw.close();
}

public void update(String fileName) throws Exception {
// sax解析器
SAXReader saxReader = new SAXReader();
// 读到对象
Document document = saxReader.read(this.getClass().getResourceAsStream(
"/" + fileName));
Element root = document.getRootElement();
List<Element> databases_node = root.elements("database");
for (Element database_node : databases_node) {
if (database_node.attributeValue("name").equalsIgnoreCase("mysql")) {
System.out.println("old:"
+ database_node.attributeValue("name"));
database_node.attribute("name").setText("Oracle");
System.out.println("update:"
+ database_node.attributeValue("name"));

database_node.element("driver").setText("oracel");
database_node.element("url").setText("jdbc");

// 删除password节点
database_node.remove(database_node.element("password"));

// 删除属性
database_node.remove(database_node.attribute("version"));
}
}

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("utf-8");
// FileOutputStream默认生成的路径在根路径
XMLWriter xw = new XMLWriter(new FileOutputStream("db2.xml"), format);
xw.write(document);
xw.close();
}

public void read(String fileName) throws Exception {
// sax解析器
SAXReader saxReader = new SAXReader();
// 读到对象
Document document = saxReader.read(this.getClass().getResourceAsStream(
"/" + fileName));
Element root = document.getRootElement();
System.out.println("根节点：" + root.getName());

// List<Element> childElements=root.elements();
List<Element> childElements = root.elements("database");
for (Element child : childElements) {
// 获取属性 不知道属性名称时的遍历方法
List<Attribute> attributes = child.attributes();
// for (Attribute attribute : attributes) {
// System.out.println(attribute.getName()+":"+attribute.getValue());
// }
String name = child.attributeValue("name");
// String version = child.attributeValue("version");
String version = child.attribute("version").getValue();
System.out.println(name + ":" + version);

// //获取子节点
// List<Element> childs=child.elements();
// for (Element element : childs) {
// System.out.println(element.getName()+":"+element.getText());
// }
System.out.println(child.elementText("driver"));
System.out.println(child.element("url").getText());
System.out.println(child.elementTextTrim("user"));
System.out.println(child.element("password").getTextTrim());

}
}

public static void main(String[] args) throws Exception {
// new Dom4jHandler().read("data-source.xml");
// new Dom4jHandler().add();
new Dom4jHandler().update("data-source.xml");
}
}