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

崔卫兵
PC学院
62354666
男,1982年生,硕士，现就读于北京邮电大学

cwb
PC学院
62358888
男,1987年生,硕士，现就读于中国农业大学


xxxxx
xxx学院
66666666
注视中，注释中


lxx
yyyy学院
88888888
注视中111，注释中222

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：或者
*/
public void getSelectedNodeValue(String filename,HashMap 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 hashMap;
Dom4jReadExmple drb=new Dom4jReadExmple();
//利用XPath操作XML文件，获取想要的属性值
hashMap = new HashMap();
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("color:black;background-color:#ffff66">element.attributeValue("id"));
departmentBean.setBh("color:black;background-color:#ffff66">element.attributeValue("bh"));
departmentBean.setName("color:black;background-color:#ffff66">element.attributeValue("name"));
departmentBean.setTel("color:black;background-color:#ffff66">element.attributeValue("tel"));
departmentBean.setAddress("color:black;background-color:#ffff66">element.attributeValue("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 = "color:black;background-color:#ffff66">element.attributeValue("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,
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
XmlElement xe1=xmldoc.CreateElement("Node");//创建一个节点
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，




候捷
58.3



候捷
58.3

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：




候捷
58.3

2，添加一个结点：

XmlDocument xmlDoc=new XmlDocument();
xmlDoc.Load(Server.MapPath("data.xml"));
XmlNode root=xmlDoc.SelectSingleNode("Employees");//查找
XmlElement xe1=xmlDoc.CreateElement("Node");//创建一个节点
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，




候捷
58.3



候捷
58.3



高手
158.3

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，




候捷
58.3



候捷
58.3



亚胜
158.3

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，




候捷
58.3
1



候捷
58.3
1



亚胜
158.3
1

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，




候捷
58.3



候捷
58.3



亚胜
158.3

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{
XmlElement xe=(XmlElement)xnl.Item(i);
if(xe.GetAttribute("genre")=="张三")
{
root.RemoveChild(xe);
if(i}
}
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：

候捷
58.3



候捷
58.3



高手
158.3



高手
158.3

删除后的内容：




候捷
58.3



候捷
58.3

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*/

something
something

/*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*/



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 *---/
--------------------------------------------------------------------



Data Source=yf; user id=ctm_dbo;password=123


--------------------------------------------------------------------------
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;
}

********************************************************************






**--------------------------------------------------------------------**
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;
}