java使用dom4j和XPath解析XML与.net 操作XML小结

最近研究java的dom4j包,使用 dom4j包来操作了xml 文件

包括三个文件：studentInfo.xml(待解析的xml文件), Dom4jReadExmple.java(解析的主要类), TestDom4jReadExmple.java(测试解析的结果) 

studentInfo.xml

<?xml version="1.0" encoding="gb2312"?>
<students>
    <student age="25"><!--如果没有age属性，默认的为20-->
        <name>崔卫兵</name>
        <college>PC学院</college>
        <telephone>62354666</telephone>
        <notes>男,1982年生,硕士，现就读于北京邮电大学</notes>
    </student>

      <student>
        <name>cwb</name>
        <college leader="学院领导">PC学院</college><!--如果没有leader属性，默认的为leader-->
        <telephone>62358888</telephone>
        <notes>男,1987年生,硕士，现就读于中国农业大学</notes>
    </student>
    <student age="45">
        <name>xxxxx</name>
        <college leader="">xxx学院</college>
        <telephone>66666666</telephone>
        <notes>注视中，注释中</notes>
    </student>
    <student age="">
        <name>lxx</name>
        <college>yyyy学院</college>
        <telephone>88888888</telephone>
        <notes>注视中111，注释中222</notes>
    </student>
</students>

Dom4jReadExmple.java

package dom4jExample.read;

import java.io.File;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
/**
 * 利用dom4j与XPath进行XML编程
 * @author cuiweibing
 * @since 2007.8.10
 */
public class Dom4jReadExmple {
 /**
  * 利用XPath操作XML文件，获取指定节点或者属性的值，并放入HashMap中
  * @param filename String 待操作的XML文件（相对路径或者绝对路径）
  * @param hm       HashMap 存放选择的结果，格式：<nodename,nodevalue>或者<nodename+attrname,attrvalue>
  */
 public void getSelectedNodeValue(String filename,HashMap<String,String> hm){
  try {
   SAXReader saxReader = new SAXReader();
   Document document = saxReader.read(new File(filename));
   //获取学生姓名为"崔卫兵"的年龄
   List list = document.selectNodes("/students/student[name="崔卫兵"]/@age");
   Iterator iter = list.iterator();
   if (iter.hasNext()) {
    Attribute attribute = (Attribute) iter.next();
    hm.put("崔卫兵-"+attribute.getName(), attribute.getValue());
   }else{
    hm.put("崔卫兵-age", "20");
   }

   //获取学生姓名为"崔卫兵"的年龄
   list = document.selectNodes("/students/student[name="cwb"]/@age");
   iter = list.iterator();
   if (iter.hasNext()) {
    Attribute attribute = (Attribute) iter.next();
    hm.put("cwb-"+attribute.getName(), attribute.getValue());
   }else{
    hm.put("cwb-age", "20");
   }

      //获取学生姓名为"cwb"所在的学院名称
   list = document.selectNodes("/students/student[name="cwb"]/college");
   iter = list.iterator();
   if (iter.hasNext()) {
     Element element = (Element) iter.next();
     String name = element.getName();
     String value = element.getText();
     hm.put("cwb-"+name, value);
   }

   //获取学生姓名为"cwb"所在学院的领导
   list = document.selectNodes("/students/student[name="cwb"]/college/@leader");
   iter = list.iterator();
   if (iter.hasNext()) {
    Attribute attribute = (Attribute) iter.next();
    hm.put("cwb-college-"+attribute.getName(), attribute.getValue());
   }else{
    hm.put("cwb-college-leader", "leader");
   }

   //获取学生姓名为"lxx"所在的学院名称
   list = document.selectNodes("/students/student[name="lxx"]/college");
   iter = list.iterator();
   if (iter.hasNext()) {
     Element element = (Element) iter.next();
     String name = element.getName();
     String value = element.getText();
     hm.put("lxx-"+name, value);
   }

   //获取学生姓名为"lxx"所在学院的领导
   list = document.selectNodes("/students/student[name="lxx"]/college/@leader");
   iter = list.iterator();
   if (iter.hasNext()) {
    Attribute attribute = (Attribute) iter.next();
    hm.put("lxx-college-"+attribute.getName(), attribute.getValue());
   }else{
    hm.put("lxx-college-leader", "leader");
   }
  } catch (Exception ex) {
   ex.printStackTrace();
  }
 }
}

TestDom4jReadExmple.java

package dom4jExample.read;

import java.util.HashMap;

/**
 * 测试Dom4jReadExmple解析的情况
 * @author cuiweibing
 * @since 2007.8.10
 */
public class TestDom4jReadExmple {
 public static void main(String[] args) {
     try{
       //获取解析完后的解析信息
       HashMap<String,String> hashMap;
       Dom4jReadExmple drb=new Dom4jReadExmple();
       //利用XPath操作XML文件，获取想要的属性值
       hashMap = new HashMap<String,String>();
       drb.getSelectedNodeValue("studentInfo.xml", hashMap);
       System.out.println("崔卫兵-age:"+hashMap.get("崔卫兵-age"));
       System.out.println("cwb-age:"+hashMap.get("cwb-age"));
       System.out.println("cwb-college:"+hashMap.get("cwb-college"));
       System.out.println("cwb-college-leader:"+hashMap.get("cwb-college-leader"));
       System.out.println("lxx-college:"+hashMap.get("lxx-college"));
       System.out.println("lxx-college-leader:"+hashMap.get("lxx-college-leader"));
     }catch(Exception ex){
       ex.printStackTrace();
     }
   }
}

 运行结果

崔卫兵-age:25
cwbage:20
cwb-college:PC学院
cwb-college-leader:学院领导
lxx-college:yyyy学院
lxx-college-leader:leader 

 弄个综合的例子：

package com.jim.beans;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

public class DepartmentBean {

    private String ID;   //主键,没有任何意义
    private String bh;   //部门编号
    private String name; //部门名称
    private String tel;  //部门电话
    private String address;  //部门地址

    private File file;   //要读取的 xml文件


    public DepartmentBean() {

    }

    public DepartmentBean(File file) {
        this.file = file;
    }

    public DepartmentBean(String id, String bh, String name, String tel, String address) {

        ID = id;
        this.bh = bh;
        this.name = name;
        this.tel = tel;
        this.address = address;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getBh() {
        return bh;
    }

    public void setBh(String bh) {
        this.bh = bh;
    }

    public String getID() {
        return ID;
    }

    public void setID(String id) {
        ID = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getTel() {
        return tel;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }

    //查询若干个部门 支持模糊查询
    public ArrayList search(String attrName,String attrValue) throws DocumentException {

        ArrayList al = new ArrayList();
        List list = null;
        //File f = new File("d:\department.xml"); //把要解析的xml文件包装成File类型
        SAXReader saxReader = new SAXReader(); //加载XML文档
        saxReader.setEncoding("UTF-8");
        Document document = saxReader.read(this.file);

        /* 采用了 dom4j 支持 xPath 这个用法 */
        if((attrName == null || attrName.trim().equals(""))
                ||(attrValue == null || attrValue.trim().equals(""))) {
            list = document.selectNodes("/departments/department");
        }else {
            //[注]: 下面这句采用的是 精确查询 等效于 某个属性=值
            //list = document.selectNodes("/departments/department[@"+attrName+"='"+attrValue+"']");
            //[注]: 下面这句采用的是 模糊查询 等效于 某个属性 like %值%
            list = document.selectNodes("/departments/department[contains(@"+attrName+",'" + attrValue + "')]");
        }

        Iterator iterator = list.iterator();
        DepartmentBean departmentBean = null;
        while(iterator.hasNext()) {

            Element element = (Element)iterator.next();
            departmentBean = new DepartmentBean();
            departmentBean.setID(<b style="color:black;background-color:#ffff66">element.attributeValue</b>("id"));
            departmentBean.setBh(<b style="color:black;background-color:#ffff66">element.attributeValue</b>("bh"));
            departmentBean.setName(<b style="color:black;background-color:#ffff66">element.attributeValue</b>("name"));
            departmentBean.setTel(<b style="color:black;background-color:#ffff66">element.attributeValue</b>("tel"));
            departmentBean.setAddress(<b style="color:black;background-color:#ffff66">element.attributeValue</b>("address"));

            al.add(departmentBean);
        }
        return al;
    }
    //查询某个部门
    public DepartmentBean getDepartment(String attrName,String attrValue) throws DocumentException {

        ArrayList al = search(attrName,attrValue);
        if(al != null && al.size() > 0) {
            return (DepartmentBean)al.get(0);
        }else {
            return null;
        }
    }

    //添加部门
    public void add(DepartmentBean newDepartmentBean)  throws DocumentException, IOException {


        Document document = DocumentHelper.createDocument();
        //创建根节点，并返回要节点
        Element departmentsElement = document.addElement("departments");
        departmentsElement.addComment("所有的部门信息");

        //向根节点departments中加入department子节点
        Element departmentElement =  null;

        departmentElement = departmentsElement.addElement("department");
        departmentElement.addAttribute("id",newDepartmentBean.getID());
        departmentElement.addAttribute("bh",newDepartmentBean.getBh());
        departmentElement.addAttribute("name",newDepartmentBean.getName());
        departmentElement.addAttribute("tel",newDepartmentBean.getTel());
        departmentElement.addAttribute("address",newDepartmentBean.getAddress());


        //File f = new File("d:\department.xml"); //把要解析的xml文件包装成File类型
        SAXReader saxReader = new SAXReader(); //加载XML文档
        saxReader.setEncoding("UTF-8");
        Document documentRead = saxReader.read(this.file);
        List list = documentRead.selectNodes("/departments/department");
        Iterator iterator = list.iterator();

        while(iterator.hasNext()) {

            departmentElement = departmentsElement.addElement("department");
            Element element = (Element)iterator.next();

            Attribute attrID = element.attribute("id");
            departmentElement.addAttribute("id",attrID.getValue());

            Attribute attrBh = element.attribute("bh");
            departmentElement.addAttribute("bh",attrBh.getValue());

            Attribute attrName = element.attribute("name");
            departmentElement.addAttribute("name",attrName.getValue());

            Attribute attrTel = element.attribute("tel");
            departmentElement.addAttribute("tel",attrTel.getValue());

            Attribute attrAddress = element.attribute("address");
            departmentElement.addAttribute("address",attrAddress.getValue());
        }

        //把修改后document写到原有的department.xml文件,以覆盖原有的department.xml文件
        XMLWriter output = new XMLWriter(new OutputStreamWriter(new FileOutputStream(this.file),"UTF-8"));
        output.write(document);
        output.close();

    }

    //编辑部门
    public void edit(String attrName,String attrValue,DepartmentBean newDepartmentBean)  throws DocumentException, IOException {

        //File f = new File("d:\department.xml"); //把要解析的xml文件包装成File类型
        SAXReader saxReader = new SAXReader(); //加载XML文档
        saxReader.setEncoding("UTF-8");
        Document document = saxReader.read(this.file);
        List list = null;
        Iterator iterator = null;
        if((attrName == null || attrName.trim().equals(""))
                ||(attrValue == null || attrValue.trim().equals(""))) { //如果设置的修改条件为 null ,则什么也不做
            return ;
        }else {
            list = document.selectNodes("/departments/department[@"+attrName+"='"+attrValue+"']");
        }

        if(list == null || list.size() == 0) { //如果设置的修改条件没有符合的记录,则什么也不做
            return ;
        }else {
            iterator = list.iterator();
            while(iterator.hasNext()) {

                Element e = (Element) iterator.next();
                Attribute attrB = e.attribute("bh");
                attrB.setValue(newDepartmentBean.getBh());
                Attribute attrN = e.attribute("name");
                attrN.setValue(newDepartmentBean.getName());
                Attribute attrT = e.attribute("tel");
                attrT.setValue(newDepartmentBean.getTel());
                Attribute attrA = e.attribute("address");
                attrA.setValue(newDepartmentBean.getAddress());
            }
        }

        //把修改后document写到原有的department.xml文件,以覆盖原有的department.xml文件
        XMLWriter output = new XMLWriter(new OutputStreamWriter(new FileOutputStream(this.file),"UTF-8"));
        output.write(document);
        output.close();
    }

    //删除部门
    public void del(String attrName,String attrValue) throws DocumentException, IOException {

        //File f = new File("d:\department.xml"); //把要解析的xml文件包装成File类型
        SAXReader saxReader = new SAXReader(); //加载XML文档
        saxReader.setEncoding("UTF-8");
        Document documentRead = saxReader.read(this.file);
        Document documentWrite = null;
        List list = null;

        if((attrName == null || attrName.trim().equals(""))
                ||(attrValue == null || attrValue.trim().equals(""))) { //如果设置的修改条件为 null ,则什么也不做
            return ;
        }else {
            list = documentRead.selectNodes("/departments/department[@"+attrName+"!='"+attrValue+"']");
        }

        documentWrite = DocumentHelper.createDocument();
        Element departmentsElement = documentWrite.addElement("departments");
        departmentsElement.addComment("所有的部门信息");

        if(list == null || list.size() == 0) { //如果是全删除了，则什么也不做

            //把修改后document写到原有的department.xml文件,以覆盖原有的department.xml文件
            XMLWriter output = new XMLWriter(new OutputStreamWriter(new FileOutputStream(this.file),"UTF-8"));
            output.write(documentWrite);
            output.close();

            return ;
        }else {
            //向根节点departments中加入department子节点
            Element departmentElement =  null;
            Iterator iterator = list.iterator();

            while(iterator.hasNext()) {

                departmentElement = departmentsElement.addElement("department");

                Element element = (Element)iterator.next();

                Attribute attrID = element.attribute("id");
                departmentElement.addAttribute("id",attrID.getValue());

                Attribute attrBh = element.attribute("bh");
                departmentElement.addAttribute("bh",attrBh.getValue());

                Attribute attrName2 = element.attribute("name");
                departmentElement.addAttribute("name",attrName2.getValue());

                Attribute attrTel = element.attribute("tel");
                departmentElement.addAttribute("tel",attrTel.getValue());

                Attribute attrAddress = element.attribute("address");
                departmentElement.addAttribute("address",attrAddress.getValue());
            }
            //把修改后document写到原有的department.xml文件,以覆盖原有的department.xml文件
            XMLWriter output = new XMLWriter(new OutputStreamWriter(new FileOutputStream(this.file),"UTF-8"));
            output.write(documentWrite);
            output.close();
        }
    }
    //得到 xml 文件中最大的主键值 + 1
    public int getMaxID() throws DocumentException {

        SAXReader saxReader = new SAXReader(); //加载XML文档
        saxReader.setEncoding("UTF-8");
        Document document = saxReader.read(this.file);

        List list = document.selectNodes("/departments/department");
        Iterator iterator = null;
        int max = 0;

        if(list == null || list.size() == 0) {
            max = 0;
        }else {

            iterator = list.iterator();
            while(iterator.hasNext()) {

                Element element = (Element)iterator.next();
                String maxStr = <b style="color:black;background-color:#ffff66">element.attributeValue</b>("id");
                int maxInt = Integer.parseInt(maxStr);
                if(maxInt > max) {
                    max = maxInt;
                }
            }
        }
        return max + 1;
    }

    public static void main(String[] args) throws DocumentException, IOException {

        File f = new File("d:\department.xml");
        DepartmentBean db = new DepartmentBean(f);
        System.out.println(db.getMaxID());
        //大家可以在这里写一些调用上面的 search ,add , del , edit 方法代码来测试测试，department.xml 文件在附件中已上传了此外还要要到两个特殊的包一个名叫jaxen-1.1.1.jar,还有一个叫dom4j-1.6.1.jar大家可以自己下载
    }
}

 

.net 操作XML小结

 一、简单介绍

using System.Xml;
//初始化一个xml实例
XmlDocument xml=new XmlDocument();

//导入指定xml文件
xml.Load(path);
xml.Load(HttpContext.Current.Server.MapPath("~/file/bookstore.xml"));

//指定一个节点
XmlNode root=xml.SelectSingleNode("/root");

//获取节点下所有直接子节点
XmlNodeList childlist=root.ChildNodes;

//判断该节点下是否有子节点
root.HasChildNodes;

//获取同名同级节点集合
XmlNodeList nodelist=xml.SelectNodes("/Root/News");

//生成一个新节点
XmlElement node=xml.CreateElement("News");

//将节点加到指定节点下，作为其子节点
root.AppendChild(node);

//将节点加到指定节点下某个子节点前
root.InsertBefore(node,root.ChildeNodes[i]);

//为指定节点的新建属性并赋值
node.SetAttribute("id","11111");

//为指定节点添加子节点
root.AppendChild(node);

//获取指定节点的指定属性值
string id=node.Attributes["id"].Value;

//获取指定节点中的文本
string content=node.InnerText;

//保存XML文件
string path=Server.MapPath("~/file/bookstore.xml");
xml.Save(path);
//or use :xml.Save(HttpContext.Current.Server.MapPath("~/file/bookstore.xml")); 

二、具体实例

在C#.net中如何操作XML
需要添加的命名空间：
using System.Xml;

定义几个公共对象：
XmlDocument xmldoc ;
XmlNode xmlnode ;
XmlElement xmlelem ;

1，创建到服务器同名目录下的xml文件：

方法一：
xmldoc = new XmlDocument ( ) ;
//加入XML的声明段落,<?xml version="1.0" encoding="gb2312"?>
XmlDeclaration xmldecl;
 xmldecl = xmldoc.CreateXmlDeclaration("1.0","gb2312",null);
 xmldoc.AppendChild ( xmldecl);

//加入一个根元素
xmlelem = xmldoc.CreateElement ( "" , "Employees" , "" ) ;
xmldoc.AppendChild ( xmlelem ) ;
//加入另外一个元素
for(int i=1;i<3;i++)
{

XmlNode root=xmldoc.SelectSingleNode("Employees");//查找<Employees> 
XmlElement xe1=xmldoc.CreateElement("Node");//创建一个<Node>节点 
xe1.SetAttribute("genre","李赞红");//设置该节点genre属性 
xe1.SetAttribute("ISBN","2-3631-4");//设置该节点ISBN属性

XmlElement xesub1=xmldoc.CreateElement("title"); 
xesub1.InnerText="CS从入门到精通";//设置文本节点 
xe1.AppendChild(xesub1);//添加到<Node>节点中 
XmlElement xesub2=xmldoc.CreateElement("author"); 
xesub2.InnerText="候捷"; 
xe1.AppendChild(xesub2); 
XmlElement xesub3=xmldoc.CreateElement("price"); 
xesub3.InnerText="58.3"; 
xe1.AppendChild(xesub3);

root.AppendChild(xe1);//添加到<Employees>节点中 
}
//保存创建好的XML文档
xmldoc.Save ( Server.MapPath("data.xml") ) ;

//////////////////////////////////////////////////////////////////////////////////////
结果：在同名目录下生成了名为data.xml的文件，内容如下，
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
</Employees>

方法二：
XmlTextWriter xmlWriter;
   string strFilename = Server.MapPath("data1.xml") ;

   xmlWriter = new XmlTextWriter(strFilename,Encoding.Default);//创建一个xml文档
   xmlWriter.Formatting = Formatting.Indented;
   xmlWriter.WriteStartDocument();
   xmlWriter.WriteStartElement("Employees");

   xmlWriter.WriteStartElement("Node");
   xmlWriter.WriteAttributeString("genre","李赞红");
   xmlWriter.WriteAttributeString("ISBN","2-3631-4");

   xmlWriter.WriteStartElement("title");
   xmlWriter.WriteString("CS从入门到精通");
   xmlWriter.WriteEndElement();

   xmlWriter.WriteStartElement("author");
   xmlWriter.WriteString("候捷");
   xmlWriter.WriteEndElement();

   xmlWriter.WriteStartElement("price");
   xmlWriter.WriteString("58.3");
   xmlWriter.WriteEndElement();

   xmlWriter.WriteEndElement();

   xmlWriter.Close();
//////////////////////////////////////////////////////////////////////////////////////
结果：
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
</Employees>

2，添加一个结点：

XmlDocument xmlDoc=new XmlDocument(); 
xmlDoc.Load(Server.MapPath("data.xml")); 
XmlNode root=xmlDoc.SelectSingleNode("Employees");//查找<Employees> 
XmlElement xe1=xmlDoc.CreateElement("Node");//创建一个<Node>节点 
xe1.SetAttribute("genre","张三");//设置该节点genre属性 
xe1.SetAttribute("ISBN","1-1111-1");//设置该节点ISBN属性

XmlElement xesub1=xmlDoc.CreateElement("title"); 
xesub1.InnerText="C#入门帮助";//设置文本节点 
xe1.AppendChild(xesub1);//添加到<Node>节点中 
XmlElement xesub2=xmlDoc.CreateElement("author"); 
xesub2.InnerText="高手"; 
xe1.AppendChild(xesub2); 
XmlElement xesub3=xmlDoc.CreateElement("price"); 
xesub3.InnerText="158.3"; 
xe1.AppendChild(xesub3);

root.AppendChild(xe1);//添加到<Employees>节点中 
xmlDoc.Save ( Server.MapPath("data.xml") );

//////////////////////////////////////////////////////////////////////////////////////
结果：在xml原有的内容里添加了一个结点，内容如下，
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="张三" ISBN="1-1111-1">
    <title>C#入门帮助</title>
    <author>高手</author>
    <price>158.3</price>
  </Node>
</Employees>

3，修改结点的值（属性和子结点）：

XmlDocument xmlDoc=new XmlDocument(); 
xmlDoc.Load( Server.MapPath("data.xml") );

XmlNodeList nodeList=xmlDoc.SelectSingleNode("Employees").ChildNodes;//获取Employees节点的所有子节点

foreach(XmlNode xn in nodeList)//遍历所有子节点 
{ 
XmlElement xe=(XmlElement)xn;//将子节点类型转换为XmlElement类型 
if(xe.GetAttribute("genre")=="张三")//如果genre属性值为“张三” 
{ 
xe.SetAttribute("genre","update张三");//则修改该属性为“update张三”

XmlNodeList nls=xe.ChildNodes;//继续获取xe子节点的所有子节点 
foreach(XmlNode xn1 in nls)//遍历 
{ 
XmlElement xe2=(XmlElement)xn1;//转换类型 
if(xe2.Name=="author")//如果找到 
{ 
xe2.InnerText="亚胜";//则修改
} 
} 
} 
} 
xmlDoc.Save( Server.MapPath("data.xml") );//保存。

//////////////////////////////////////////////////////////////////////////////////////
结果：将原来的所有结点的信息都修改了，xml的内容如下，
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="update张三" ISBN="1-1111-1">
    <title>C#入门帮助</title>
    <author>亚胜</author>
    <price>158.3</price>
  </Node>
</Employees>

4，修改结点（添加结点的属性和添加结点的自结点）：
XmlDocument xmlDoc=new XmlDocument(); 
xmlDoc.Load( Server.MapPath("data.xml") );

XmlNodeList nodeList=xmlDoc.SelectSingleNode("Employees").ChildNodes;//获取Employees节点的所有子节点

foreach(XmlNode xn in nodeList) 
{ 
XmlElement xe=(XmlElement)xn; 
xe.SetAttribute("test","111111");

XmlElement xesub=xmlDoc.CreateElement("flag"); 
xesub.InnerText="1"; 
xe.AppendChild(xesub); 
} 
xmlDoc.Save( Server.MapPath("data.xml") );

//////////////////////////////////////////////////////////////////////////////////////
结果：每个结点的属性都添加了一个，子结点也添加了一个，内容如下，
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4" test="111111">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
    <flag>1</flag>
  </Node>
  <Node genre="李赞红" ISBN="2-3631-4" test="111111">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
    <flag>1</flag>
  </Node>
  <Node genre="update张三" ISBN="1-1111-1" test="111111">
    <title>C#入门帮助</title>
    <author>亚胜</author>
    <price>158.3</price>
    <flag>1</flag>
  </Node>
</Employees>

5，删除结点中的某一个属性：
XmlDocument xmlDoc=new XmlDocument(); 
xmlDoc.Load( Server.MapPath("data.xml") ); 
XmlNodeList xnl=xmlDoc.SelectSingleNode("Employees").ChildNodes; 
foreach(XmlNode xn in xnl) 
{ 
XmlElement xe=(XmlElement)xn; 
xe.RemoveAttribute("genre");//删除genre属性

XmlNodeList nls=xe.ChildNodes;//继续获取xe子节点的所有子节点 
foreach(XmlNode xn1 in nls)//遍历 
{ 
XmlElement xe2=(XmlElement)xn1;//转换类型 
if(xe2.Name=="flag")//如果找到 
{ 
xe.RemoveChild(xe2);//则删除
} 
} 
} 
xmlDoc.Save( Server.MapPath("data.xml") );

//////////////////////////////////////////////////////////////////////////////////////]
结果：删除了结点的一个属性和结点的一个子结点，内容如下，
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node ISBN="2-3631-4" test="111111">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node ISBN="2-3631-4" test="111111">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node ISBN="1-1111-1" test="111111">
    <title>C#入门帮助</title>
    <author>亚胜</author>
    <price>158.3</price>
  </Node>
</Employees>

6，删除结点：
XmlDocument xmlDoc=new XmlDocument(); 
xmlDoc.Load( Server.MapPath("data.xml") ); 
XmlNode root=xmlDoc.SelectSingleNode("Employees");
XmlNodeList xnl=xmlDoc.SelectSingleNode("Employees").ChildNodes; 
for(int i=0;i<xnl.Count;i++)
{
XmlElement xe=(XmlElement)xnl.Item(i); 
if(xe.GetAttribute("genre")=="张三") 
{ 
root.RemoveChild(xe);
if(i<xnl.Count)i=i-1;
} 
}
xmlDoc.Save( Server.MapPath("data.xml") );

//////////////////////////////////////////////////////////////////////////////////////]
结果：删除了符合条件的所有结点，原来的内容：

<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="张三" ISBN="1-1111-1">
    <title>C#入门帮助</title>
    <author>高手</author>
    <price>158.3</price>
  </Node>
  <Node genre="张三" ISBN="1-1111-1">
    <title>C#入门帮助</title>
    <author>高手</author>
    <price>158.3</price>
  </Node>
</Employees>

删除后的内容：
<?xml version="1.0" encoding="gb2312"?>
<Employees>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
  <Node genre="李赞红" ISBN="2-3631-4">
    <title>CS从入门到精通</title>
    <author>候捷</author>
    <price>58.3</price>
  </Node>
</Employees>

 7，按照文本文件读取xml

System.IO.StreamReader myFile =new 
System.IO.StreamReader(Server.MapPath("data.xml"),System.Text.Encoding.Default);
//注意System.Text.Encoding.Default

string myString = myFile.ReadToEnd();//myString是读出的字符串
myFile.Close();

三、高级应用 

/*读取xml数据   两种xml方式*/
<aaa>
     <bb>something</bb>
     <cc>something</cc>
</aaa>
 
<aaa>
    <add key="123" value="321"/>
</aaa>

/*第一种方法*/
DS.ReadXml("your xmlfile name");
Container.DataItem("bb");
Container.DataItem("cc");
DS.ReadXmlSchema("your xmlfile name");
 
/*第二种方法*/
<aaa>
    <add key="123" value="321"/>
</aaa>
如果我要找到123然后取到321应该怎么写呢？
 
using System.XML;
XmlDataDocument xmlDoc = new System.Xml.XmlDataDocument();
xmlDoc.Load(@"c:Config.xml");
XmlElement elem = xmlDoc.GetElementById("add");
string str = elem.Attributes["value"].Value
 
 
/*第三种方法:  SelectSingleNode  读取两种格式的xml *---/
--------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <appSettings>
       <ConnectionString>Data Source=yf; user id=ctm_dbo;password=123</ConnectionString>             
  </appSettings>
</configuration>
--------------------------------------------------------------------------
XmlDocument doc = new XmlDocument();
doc.Load(strXmlName);
 
    XmlNode node=doc.SelectSingleNode("/configuration/appSettings/ConnectionString");
    if(node!=null)
    {
     string k1=node.Value;    //null
     string k2=node.InnerText;//Data Source=yf; user id=ctm_dbo;password=123
     string k3=node.InnerXml;//Data Source=yf; user id=ctm_dbo;password=123
     node=null;
    }
 
********************************************************************
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <appSettings>
       <add key="ConnectionString" value="Data Source=yf; user id=ctm_dbo;password=123" />             
  </appSettings>
</configuration>
**--------------------------------------------------------------------**
     XmlNode node=doc.SelectSingleNode("/configuration/appSettings/add");
    if(node!=null)
    {
     string k=node.Attributes["key"].Value;
     string v=node.Attributes["value"].Value;
     node=null;
    }
*--------------------------------------------------------------------*
    XmlNode node=doc.SelectSingleNode("/configuration/appSettings/add");
    if(node!=null)
    {
     XmlNodeReader nr=new XmlNodeReader(node);
     nr.MoveToContent();
    //检查当前节点是否是内容节点。如果此节点不是内容节点，则读取器向前跳至下一个内容节点或文件结尾。
     nr.MoveToAttribute("value");
     string s=nr.Value;
     node=null;
    }