dom4j对XML数据文件的增删查改操作

当然，首先要把dom4j.jar加入库文件

package xml;

import java.io.File;
import java.io.FileWriter;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;


/**
*
* @author estcele
*/
public class Dom4jDemo {

    /** Creates a new instance of Dom4jDemo */
    public Dom4jDemo() {
    }
    /**
     *The method createXML
     *建立一个XML文档,文档名由输入属性决定
     *@param filename 需建立的文件名
     *@return 返回操作结果
     */
    public boolean createXML(String fileName){
        boolean isOk = false;
        //建立document对象
        Document doc = DocumentHelper.createDocument();
        //建立XML文档的根books
        Element books = doc.addElement("books");
        books.addComment("This is a test for dom4j");//加入一行注释
        Element book = books.addElement("book");//加入第一个book节点
        book.addAttribute("show", "yes");//加入show属性内容
        Element title = book.addElement("title");//加入title节点
        title.setText("Dom4j Tutorials");//为title设置内容
        /**加入第二个book节点*/
        book = books.addElement("book");
        book.addAttribute("show", "yes");
        title = book.addElement("title");
        title.setText("Lucene Studing");
        /**加入第三个book节点*/
        book = books.addElement("book");
        book.addAttribute("show", "no");
        title = book.addElement("title");
        title.setText("Lucene in Action");
        /**加入owner节点*/
        Element owner = books.addElement("owner");
        owner.setText("O'Reilly");
        /**
         *将doc中的内容写入xml文件中
         **/
        try{
            FileWriter file = new FileWriter(new File(fileName));
            XMLWriter writer = new XMLWriter(file);
            writer.write(doc);
            writer.close();
            isOk = true;
        }catch(Exception e){
            e.printStackTrace();
        }
        return isOk;
    }
   /**
     *the method modifigXML
     *     如果book节点中show属性的内容为yes,则修改成no
     *     把owner项内容改为Tshinghua，并添加date节点
     *     若title内容为Dom4j Tutorials,则删除该节点
     */
    public boolean modifigXML(String oldFileName,String newFileName){
        boolean isOk = false;
        try{
            SAXReader reader = new SAXReader();
            Document doc = reader.read(new File(oldFileName));
            /**修改内容之一: 如果book节点中show属性的内容为yes,则修改成no*/
            List list = doc.selectNodes("/books/book/@show");
            Iterator iter = list.iterator();
            while(iter.hasNext()){
                Attribute attr = (Attribute)iter.next();
                if(attr.getValue().equals("yes"))
                    attr.setValue("no");
            }
            /**
             *修改内容之二: 把owner项内容改为Tshinghua
             *并在owner节点中加入date节点,
             * date节点的内容为2004-09-11,
             * 还为date节点添加一个属性type
             */
            list = doc.selectNodes("/books/owner");
            iter = list.iterator();
            if(iter.hasNext()){
                Element owner = (Element)iter.next();
                owner.setText("Tshinghua");
                Element date = owner.addElement("date");
                date.setText("2006-07-30");
                date.addAttribute("type", "Gregorian calendar");
            }
           /**修改内容之三: 若title内容为Dom4j Tutorials,则删除该节点*/
            list = doc.selectNodes("/books/book");
            iter = list.iterator();
            while(iter.hasNext()){
                Element elem = (Element)iter.next();
                Iterator iterElem = elem.elementIterator("title");
                if(iterElem.hasNext()){
                    Element remTitle = (Element)iterElem.next();
                    if(remTitle.getText().trim().equals("Dom4j Tutorials"))
                        elem.remove(remTitle);
                }
            }
            //将doc中的内容写入文件中
            try{
                FileWriter newFile = new FileWriter(new File(newFileName));
                XMLWriter newWriter = new XMLWriter(newFile);
                newWriter.write(doc);
                newWriter.close();
            }catch(Exception e){
                e.printStackTrace();
            }
            isOk = true;
        }catch(Exception e){
            e.printStackTrace();
        }
        return isOk;
    }
    /**
     *the method formatXML
     *-------------------------
     *默认的输出方式为紧凑方式，默认编码为UTF-8，
     * 但对于我们的应用而言，一般都要用到中文，
     * 并且希望显示时按自动缩进的方式的显示，这就需用到OutputFormat类。
     */
    public boolean formatXML(String fileName){
        boolean isOk = false;
        try{
            SAXReader reader = new SAXReader();
            Document doc = reader.read(new File(fileName));
            XMLWriter formatWriter = null;
            /**
             *格式化输出,类型IE浏览一样
             *指定XML编码
             */
            OutputFormat format = OutputFormat.createPrettyPrint();
            format.setEncoding("gb2312");
            formatWriter = new XMLWriter(new FileWriter(new File(fileName)), format);
            formatWriter.write(doc);
            formatWriter.close();

            isOk = true;
        }catch(Exception e){
            e.printStackTrace();
        }
        return isOk;
    }
   /**
     *the method readXML
     */
    public void readXML(String fileName){
        try{
            SAXReader reader = new SAXReader();
            Document doc = reader.read(new File(fileName));
            List list = doc.selectNodes("/books/book");
            Iterator iter = list.iterator();
            while(iter.hasNext()){
                Element book = (Element)iter.next();
                Iterator title = book.elementIterator("title");
                if(title.hasNext()){
                    Element elemTitle = (Element)title.next();
                    System.out.print("Title: "+elemTitle.getText());
                    System.out.print("   Show: "+book.attributeValue("show")+"\n");
                }
            }

            list = doc.selectNodes("/books/owner");
            iter = list.iterator();
            if(iter.hasNext()){
                Element owner = (Element)iter.next();
                System.out.println("Owner: "+owner.getText());
                System.out.println("Date: "+owner.elementText("date"));
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
   /*
    Title: Dom4j Tutorials   Show: yes
    Title: Lucene Studing   Show: yes
    Title: Lucene in Action   Show: no
   Owner: O'Reilly
   Date: null
    */
    /**
     *the method main
     */
    public static void main(String[] args){
        long start = System.currentTimeMillis();//开始计时
        Dom4jDemo dom4jDemo = new Dom4jDemo();
        String fileName = "dom4jDemo.xml";
        String newFileName = "new_dom4jDemo.xml";
        System.out.println(fileName+"正在创建中...");
        boolean isOk_create = dom4jDemo.createXML(fileName);
        if(isOk_create) System.out.println(fileName+"创建成功!");
        else System.out.println("创建失败!请检查后重新再试!");

        System.out.println("正在更新中...");
        boolean isOk_modi = dom4jDemo.modifigXML(fileName, newFileName);
        if(isOk_modi) System.out.println("恭喜,更新完成!");
        else System.out.println("更新失败!请检查后重新再试!");

        System.out.println("正在格式化中...");
        boolean isOk_format = dom4jDemo.formatXML(fileName);
        if(isOk_format) System.out.println("恭喜,格式化完成!");
        else System.out.println("格式化失败!请检查后重新再试!");

        System.out.println("正在读取文件 "+fileName+" ...");
        System.out.println("------------------------------------------------");
        dom4jDemo.readXML(fileName);
        System.out.println("------------------------------------------------");
        System.out.println(fileName+"读取成功!");
        System.out.println("正在读取文件 "+newFileName+" ...");
        System.out.println("------------------------------------------------");
        dom4jDemo.readXML(newFileName);
        System.out.println("------------------------------------------------");
        System.out.println(fileName+"读取成功!");
        System.out.println("一共耗时： "+(System.currentTimeMillis()-start)+"毫秒!");
    }
}