package com.gnnuit.dom4j;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test;

/**
 * 使用Dom4j操作文件的CUD
 * 
 * @author YLY
 * 
 */
public class Demo2 {
    @Test
    public void create() throws Exception {
        Document document = getDocument();
        Element rootElement = document.getRootElement();
        // 取得第一辆汽车
        Element firstElement = (Element) rootElement.elements().get(0);
        // 添加新元素“单价”，并设置文本为30
        firstElement.addElement("单价").setText("30");
        // 将内存中的XML写到硬盘中
        write2xml(document);
    }

    @Test
    public void update() throws Exception {
        Document document = getDocument();
        Element rootElement = document.getRootElement();
        // 获得第一辆汽车
        Element firstElement = (Element) rootElement.elements().get(0);
        // 将第一辆汽车的单价修改为50万
        firstElement.element("单价").setText("50万");
        write2xml(document);
    }

    @Test
    public void delete() throws Exception {
        Document document = getDocument();
        Element rootElement = document.getRootElement();
        // 获得第一辆汽车
        Element firstElement = (Element) rootElement.elements().get(0);
        // 删除第一辆汽车的“单价”元素
        Element firstCarPriceElement = firstElement.element("单价");
        // 删除第一种方法
        // firstElement.remove(firstCarPriceElement);
        // 删除第二种方法
        firstCarPriceElement.getParent().remove(firstCarPriceElement);
        write2xml(document);
    }

    /**
     * 将内存中的XML写到硬盘
     * 
     * @param document
     * @throws FileNotFoundException
     * @throws UnsupportedEncodingException
     * @throws IOException
     */
    private void write2xml(Document document) throws FileNotFoundException,
            UnsupportedEncodingException, IOException {
        OutputStream out = new FileOutputStream(new File(
                "src/com/gnnuit/dom4j/car.xml"));
        OutputFormat format = OutputFormat.createPrettyPrint();
        XMLWriter writer = new XMLWriter(out, format);
        writer.write(document);
        writer.close();
    }

    /**
     * 获取Document对象
     * 
     * @return
     * @throws DocumentException
     */
    private Document getDocument() throws DocumentException {
        SAXReader saxReader = new SAXReader();
        Document document = saxReader.read(new File(
                "src/com/gnnuit/dom4j/car.xml"));
        return document;
    }
}

package com.gnnuit.sax;

import java.io.File;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

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

public class Demo1 {

    public static void main(String[] args) throws Exception {
        // 创建SAX解析器工厂
        SAXParserFactory factory = SAXParserFactory.newInstance();
        // 创建SAX解析器
        SAXParser parse = factory.newSAXParser();
        // 加载xml文件
        parse.parse(new File("src/com/gnnuit/sax/car.xml"), new MyHandler());
    }
}

// 自定义SAX处理器
class MyHandler extends DefaultHandler {
    public void startDocument() {
        System.out.println("文档开始");
    }

    public void endDocument() {
        System.out.println("文档结束");
    }

    public void startElement(String uri, String localName, String qName,
            Attributes attributes) {
        System.out.println("<" + qName + ">");
    }

    public void endElement(String uri, String localName, String qName) {
        System.out.println("</" + qName + ">");
    }

    public void characters(char[] ch, int start, int length) {
        String content = new String(ch, start, length).trim();
        if (content.length() > 0) {
            System.out.println(content);
        }
    }
}