java xml 增加tag

XML文件   poem.xml
<?xml version="1.0" encoding="UTF-8"?>
 <poems>
   <poem id="1" title="观沧海" author="曹操">
     <content>树木丛生，百草丰茂。秋风萧瑟，洪波涌起。</content>
     <explain>树木</explain>
   </poem>
   <poem id="2" title="饮酒" author="陶渊明">
     <content>结庐在人境，而无车马喧。问君何能尔？心远地自偏。</content>
     <explain>结庐</explain>
   </poem>
 </poems>
C#操作XML

引入命名空间
using System.IO;
 using System.Xml;
static void Main(string[] args)
         {
             string idvalue = "1";
             string titlevalue = "观沧海";
             string authorvalue = "曹操";
             string contentvalue = "树木丛生，百草丰茂。秋风萧瑟，洪波涌起。";
             string explainvalue = "树木";
             //新建对象
             XmlDocument doc = new XmlDocument();
             //如果poem.xml文件不存在,则重新创建并写入xml节点和根节点
             if (!File.Exists("poem.xml"))
             {
                //XML版本和编码声明
                doc.AppendChild(doc.CreateXmlDeclaration("1.0", "UTF-8", null));
                //添加根元素
                doc.AppendChild(doc.CreateElement("poems"));


                //获取根节点
                XmlNode rootpoems = doc.SelectSingleNode("/poems");
                //新建poem节点
                XmlNode newpoem = doc.CreateElement("poem");
                //新建id属性
                XmlAttribute tempatt = doc.CreateAttribute("id");
                 tempatt.Value = idvalue;
                //添加属性
                newpoem.Attributes.Append(tempatt);
                 tempatt = doc.CreateAttribute("title");
                 tempatt.Value = titlevalue;
                 newpoem.Attributes.Append(tempatt);
                 tempatt = doc.CreateAttribute("author");
                 tempatt.Value = authorvalue;
                 newpoem.Attributes.Append(tempatt);
                 XmlNode tempnode = doc.CreateElement("content");
                 tempnode.InnerText = contentvalue;
                //添加节点
                newpoem.AppendChild(tempnode);
                 tempnode = doc.CreateElement("explain");
                 tempnode.InnerText = explainvalue;
                 newpoem.AppendChild(tempnode);
                 rootpoems.AppendChild(newpoem);


                //保存（若只访问，则不用保存）
                doc.Save("poem.xml");
             }
            //加载xml文件
            doc.Load("poem.xml");
            //获取根节点
            XmlNode poems = doc.SelectSingleNode("poems");
            //获取poem节点集合
            XmlNodeList poemss = poems.SelectNodes("poem");
            //根据属性查找节点，若有多个，则SelectSingleNode方法返回第一个
            XmlNode poemvalue1 = poems.SelectSingleNode("poem[@id='" + idvalue + "']");
            //根据多属性查找节点
            XmlNode poemvalue2 = poems.SelectSingleNode("poem[@id='" + idvalue + "' and @title='" + titlevalue + "']");
            //根据子节点内容查找节点
            XmlNode poemvalue3 = poems.SelectSingleNode("poem[explainvalue='" + explainvalue + "']");
            //根据节点内容查找节点
            XmlNode poemvalue4 = poems.SelectSingleNode("poem/content[text()='"+contentvalue+"']");
             //查找最后一个节点            XmlNode poemvalue5 = poems.SelectSingleNode("poem[last()]");
            //修改节点值
            poemvalue4.InnerText = explainvalue;
            //修改节点属性值
            poemvalue1.Attributes["title"].Value = "sun";


            //获取最后一个节点的id值
            try
             {
                 if (poemss.Count > 0)
                     idvalue = (Int32.Parse(poemss[poemss.Count - 1].Attributes["id"].Value) + 1).ToString();
             }
             catch {  }
            //删除第一个poem节点
            poems.RemoveChild(poemss[0]);
             
            //保存（若只访问，则不用保存）
            doc.Save("poem.xml");
         }


java操作XML
需要先导入dom4j和jaxen架包
免费下载地址：
引入命名空间
import java.io.File;
 import java.io.FileWriter;
 import java.util.List;
 import org.dom4j.Document;
 import org.dom4j.DocumentHelper;
 import org.dom4j.Element;
 import .OutputFormat;
 import .SAXReader;
 import .XMLWriter;

public static void main(String[] args) throws Exception {
String idvalue = "1";
         String titlevalue = "观沧海";
         String authorvalue = "曹操";
         String contentvalue = "树木丛生，百草丰茂。秋风萧瑟，洪波涌起。";
         String explainvalue = "树木";
         
         //声明文档对象
         Document doc=null;
        //如果poem.xml文件不存在,则重新创建并写入xml节点和根节点
        if (!new File("poem.xml").exists())
         {
//创建xml
        doc=DocumentHelper.createDocument();
         //添加根元素
         Element poems=doc.addElement("poems");
         //新建poem节点，添加id，title，author属性。因为操作结果返回原节点，所以可连续添加。
         Element poem=poems.addElement("poem").addAttribute("id", idvalue).addAttribute("title", titlevalue).addAttribute("author", authorvalue);
         //添加子节点
             Element content=poem.addElement("content");
         //给节点赋值
             content.setText(contentvalue);
         Element explain=poem.addElement("explain");
         explain.setText(explainvalue);
         
             //保存xml文件
         OutputFormat format = OutputFormat.createPrettyPrint(); 
             //设置编码
         format.setEncoding("UTF-8"); 
         //写入
         XMLWriter writer=new XMLWriter(new FileWriter(new File("poem.xml")), format);
writer.write(doc);
writer.close();
         }
         //新建对象
         SAXReader reader=new SAXReader();
         //加载xml文件
         doc = reader.read(new File("poem.xml"));
         //获取根节点
         Element poems = (Element) doc.selectSingleNode("/poems");
         //获取poem节点集合
         List poemss = poems.selectNodes("poem");
         //根据属性查找节点，若有多个，则SelectSingleNode方法返回第一个
         Element poemvalue1 = (Element) poems.selectSingleNode("poem[@id='" + idvalue + "']");
         //根据多属性查找节点
         Element poemvalue2 = (Element) poems.selectSingleNode("poem[@id='" + idvalue + "' and @title='" + titlevalue + "']");
         //根据子节点内容查找节点
         Element poemvalue3 = (Element) poems.selectSingleNode("poem[explainvalue='" + explainvalue + "']");
         //根据节点内容查找节点
         Element poemvalue4 = (Element) poems.selectSingleNode("poem/content[text()='"+contentvalue+"']");
         //获取最后一个节点
         Element poemvalue5 = (Element) poems.selectSingleNode("poem[last()]");
         
         //修改节点值
         poemvalue4.setText(explainvalue);
         //修改节点属性值
         poemvalue1.setAttributeValue("author", "sun");


         //获取最后一个节点的id值
         if (poemss.size() > 0)
             idvalue = String.valueOf((Integer.parseInt(((Element)poemss.get(poemss.size() - 1)).attributeValue("id")) + 1));
         
         //删除最后一个poem节点
         poems.remove(poemvalue5);
         
         //保存（若只访问，则不用保存）
         //设置编码
     OutputFormat format = OutputFormat.createPrettyPrint(); 
         //设置编码
     format.setEncoding("UTF-8"); 
     //写入
     XMLWriter writer=new XMLWriter(new FileWriter(new File("poem.xml")), format);
writer.write(doc);
writer.close();
}