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��Z��spring+dwr+xml无刷新投��?调查)�pȝ��

flustar — Mon, 19 Nov 2007 10:04:00 GMT

一、徏立xml的数据结构，文�g名�ؓ�Q�vote.xml�Q�内容如下：

在你的web应用的根目录建立xml文�g夹，��其拯��到该目录下�?/p>

二、徏立xml对应的bean

/**

* @author flustar

* @version 创徏旉��Q�Jul 11, 2007 5:17:53 PM

* �c�说�?/p>

……………………………………………………………………….

public class VoteBean {

private String voteId;

private String name;

private String voteCount;

private String voteTotalCount;

private String percentum;

public VoteBean() {

}

public String getPercentum() {

return percentum;

}

public void setPercentum(String percentum) {

this.percentum = percentum;

}

public String getVoteId() {

return voteId;

}

public void setVoteId(String voteId) {

this.voteId = voteId;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getVoteCount() {

return voteCount;

}

public void setVoteCount(String voteCount) {

this.voteCount = voteCount;

}

三、徏立处理具体逻辑的service

package com.flustar.service;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.text.NumberFormat;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import org.jdom.Attribute;

import org.jdom.Document;

import org.jdom.Element;

import org.jdom.input.SAXBuilder;

import org.jdom.output.Format;

import org.jdom.output.XMLOutputter;

import org.jdom.xpath.XPath;

import com.flustar.web.beans.VoteBean;

import com.flustar.web.config.ContextConfig;

public class VoteService {

private Element root, vote;

private Document doc;

private Attribute voteTotalCount;

private VoteBean voteBean;

private List voteBeanList;

private String path = ContextConfig.getContextPath()

+ "/xml/vote.xml";

public void buildDoc() throws Exception {

FileInputStream fi = null;

fi = new FileInputStream(path);

SAXBuilder sb = new SAXBuilder();

doc = sb.build(fi);

}

public void formatDoc() throws Exception {

Format format = Format.getCompactFormat();

format.setEncoding("UTF-8");// 讄��xml文�g的字�W��ؓUTF-8

format.setIndent(" ");// 讄��xml文�g�~�进�?个空�?/p>

XMLOutputter xmlOut = new XMLOutputter(format);

xmlOut.output(doc, new FileOutputStream(path));

}

public String floatToPercentum(Double doubleNum) {

NumberFormat numberFormat = NumberFormat.getPercentInstance();

numberFormat.setMinimumFractionDigits(2);

// numberFormat.setMaximumIntegerDigits(2);

String str = numberFormat.format(doubleNum);

//System.out.println(str);

return str;

}

public void updateVoteCount(String voteId) throws Exception {

buildDoc();

root = doc.getRootElement();

vote = (Element) XPath.selectSingleNode(root, "http://vote[@voteId='"

+ voteId + "']");

int voteCount = Integer.parseInt(vote.getAttributeValue("voteCount")) + 1;

//System.out.println(voteCount);

vote.setAttribute("voteCount", String.valueOf(voteCount));

int totalCount = Integer.parseInt(root

.getAttributeValue("voteTotalCount")) + 1;

voteTotalCount = new Attribute("voteTotalCount", String

.valueOf(totalCount));

root.setAttribute(voteTotalCount);

System.out.println(totalCount);

formatDoc();

updateAllVoteCount();//更新所有的癑ֈ��?/p>

}

public void updateAllVoteCount()throws Exception{

buildDoc();

root=doc.getRootElement();

int totalCount = Integer.parseInt(root

.getAttributeValue("voteTotalCount"));

List voteList=XPath.selectNodes(root,"/votes/vote");

for(int i=0;i

vote=(Element)voteList.get(i);

int voteCount = Integer.parseInt(vote.getAttributeValue("voteCount"));

System.out.println(voteCount);

vote.setAttribute("voteCount", String.valueOf(voteCount));

vote.setAttribute("percentum", floatToPercentum(1.0 * voteCount

/ totalCount));

}

formatDoc();

}

public List getAllVote() throws Exception {

buildDoc();

voteBeanList = new ArrayList();

root = doc.getRootElement();

String totalCount = root.getAttributeValue("voteTotalCount");

List voteList = root.getChildren();

Iterator i = voteList.iterator();

while (i.hasNext()) {

voteBean = new VoteBean();

voteBean.setVoteTotalCount(totalCount);

vote = (Element) i.next();

String name = vote.getAttributeValue("name");

String voteCount = vote.getAttributeValue("voteCount");

String percentum = vote.getAttributeValue("percentum");

voteBean.setName(name);

voteBean.setVoteCount(voteCount);

voteBean.setPercentum(percentum);

voteBeanList.add(voteBean);

}

return voteBeanList;

}

public String getVoteTotalCount() {

return voteTotalCount;

}

public void setVoteTotalCount(String voteTotalCount) {

this.voteTotalCount = voteTotalCount;

}

四、获取上下文路径的listener

package com.flustar.web.listener;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

import com.flustar.web.config.ContextConfig;

public class ConfigLoadContextListener implements ServletContextListener{

public void contextDestroyed(ServletContextEvent arg0) {

// TODO Auto-generated method stub

}

public void contextInitialized(ServletContextEvent contextEvent) {

// TODO Auto-generated method stub

String contextPath = contextEvent.getServletContext().getRealPath("/");

ContextConfig.setContextPath(contextPath);

}

………………………………………………………..

……………………………………………………………

public class ContextConfig {

private static String contextPath;

public static String getContextPath() {

return contextPath;

}

public static void setContextPath(String contextPath) {

ContextConfig.contextPath = contextPath;

}

……………………………………………………………………

………………………………………………………………..

}

五、在applicationContext-service.xml中注册VoteService

六、注册xml�Q�在你的web应用的WEB-INFO目录下徏立applicationContext-dwr.xml文�g�Q�内容�ؓ�Q?/p>

七、修改web.xml

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"

version="2.4">

…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………..

contextConfigLocation

…………………………………..

/WEB-INF/classes/applicationContext-service.xml

……………………………………………………………………………………………………………………………………………. com.flustar.web.listener.ConfigLoadContextListener

…………………………………………………………………………………………………………………………………………….

dwr-invoker

org.directwebremoting.servlet.DwrServlet

debug

true

dwr-invoker

/dwr/*

…………………………………………………………………………………………………………………………………………….

八、jsp��面

<%@ page contentType="text/html; charset=gbk" language="java" import="java.sql.*" errorPage="" %>

投票�pȝ��

你��用最多的一门语�a�是？

C语言

c++

java

汇编语言

投票�l�果

投票�l�果
语言	癑ֈ��?lt;/th>	��数

�?lt;span id="totalCount">条投��?lt;br/>

[关闭�H�口]

flustar 2007-11-19 18:04 发表评论

flustar — Sun, 29 Apr 2007 06:08:00 GMT

JDOM是一个开源项目，它基于树型结构，利用�U�JAVA的技术对XML文档实现解析、生成、序列化以及多种操作�?/strong>

一、JDOM ��?/p>
JDOM是一个开源项目，它基于树型结构，利用�U�JAVA的技术对XML文档实现解析、生成、序列化以及多种操作�?/p>
JDOM 直接为JAVA�~�程服务。它利用更�ؓ强有力的JAVA语言的诸多特性（�Ҏ��重蝲、集合概念以及映��）�Q�把SAX和DOM的功能有效地�l�合��h��?/p>
在��用设计上��可能地隐藏原来使用XML�q�程中的复杂性。利用JDOM处理XML文档��是一件轻松、简单的事�?/p>
JDOM �?000�q�的春天被Brett McLaughlin和Jason Hunter开发出来，以��I补DOM及SAX在实际应用当中的不��之处�?/p>
�q�些不��之处主要在于SAX没有文档修改、随��问以及输出的功能�Q�而对于DOM来说�Q�JAVA�E�序员在使用时来用�v来总觉得不太方�ѝ�?/p>
DOM的缺点主要是来自于由于Dom是一个接口定义语�a��Q�IDL�Q?它的��d��是在不同语言实现中的一个最低的通用标准�Q��ƈ不是为JAVA特别设计的。JDOM的最新版本�ؓJDOM Beta 9。最�q�JDOM被收录到JSR-102内，�q�标志着JDOM成�ؓ了JAVA�q�_��l�成的一部分�?/p>
二、JDOM 包概�?/p>
JDOM是由以下几个包组成的
org.jdom                包含了所有的xml文档要素的java�c?/p>

org.jdom.adapters         包含了与dom适配的java�c?/p>

org.jdom.filter            包含了xml文档的过滤器�c?/p>

org.jdom.input            包含了读取xml文档的类

org.jdom.output           包含了写入xml文档的类

org.jdom.transform        包含了将jdom xml文档接口转换为其他xml文档接口

org.jdom.xpath            包含了对xml文档xpath操作的类三、JDOM �c�说�?/p>
1、org.JDOM�q�个包里的类是你J解析xml文�g后所要用到的所有数据类型�?/p>
Attribute

CDATA

Coment

DocType

Document

Element

EntityRef

Namespace

ProscessingInstruction

Text

2、org.JDOM.transform在涉及xslt格式转换时应使用下面�?个类

JDOMSource

JDOMResult

org.JDOM.input

3、输入类�Q�一般用于文档的创徏工作

SAXBuilder

DOMBuilder

ResultSetBuilder

org.JDOM.output

4、输出类�Q�用于文档�{换输�?/p>
XMLOutputter

SAXOutputter

DomOutputter

JTreeOutputter

使用前注意事��：

1.JDOM对于JAXP 以及 TRax 的支�?/p>
JDOM 支持JAXP1.1�Q�你可以在程序中使用��M��的parser工具�c?默认情况下是JAXP的parser�?/p>
制定特别的parser可用如下形式

SAXBuilder parser

= new SAXBuilder("org.apache.crimson.parser.XMLReaderImpl");

Document doc = parser.build("http://www.cafeconleche.org/");

// work with the document...

JDOM也支持TRaX�Q�XSLT可通过JDOMSource以及JDOMResult�c�L��转换�Q�参见以后章节）

2.注意在JDOM里文档（Document�Q�类由org.JDOM.Document 来表�C�。这要与org.w3c.dom中的Document区别开�Q�这2�U�格式如何�{换在后面会说明�?/p>
以下如无�Ҏ��均指JDOM里的Document�?/p>
四、JDOM主要使用�Ҏ��

1.Ducument�c?/p>
(1)Document的操作方法：

Element root = new Element("GREETING");

Document doc = new Document(root);

root.setText("Hello JDOM!");

或者简单的使用Document doc = new Document(new Element("GREETING").setText("Hello JDOM!t"));

�q�点和DOM不同。Dom则需要更为复杂的代码�Q�如下：

DocumentBuilderFactory factory =DocumentBuilderFactory.newInstance();

DocumentBuilder builder =factory.newDocumentBuilder();

Document doc = builder.newDocument();

Element root =doc.createElement("root");

Text text = doc.createText("This is the root");

root.appendChild(text);

doc.appendChild(root);

注意事项�Q�JDOM不允许同一个节点同时被2个或多个文档相关联，要在�W?个文档中使用原来老文档中的节点的话。首先需要��用detach()把这个节点分开来�?/p>
(2)从文件、流、系�l�ID、URL得到Document对象�Q?/p>
DOMBuilder builder = new DOMBuilder();

Document doc = builder.build(new File("jdom_test.xml"));

SAXBuilder builder = new SAXBuilder();

Document doc = builder.build(url);

在新版本中DOMBuilder 已经Deprecated�?DOMBuilder.builder(url)�Q�用SAX效率会比较快�?/p>
�q�里举一个小例子�Q��ؓ了简单�v见，使用String对象直接作�ؓxml数据源：

public jdomTest() {

    String textXml = null;

    textXml = "";

    textXml = textXml +

        "aaabbbcccddd";

    textXml = textXml + "";

    SAXBuilder builder = new SAXBuilder();

    Document doc = null;

    Reader in= new StringReader(textXml);

    try {

      doc = builder.build(in);

      Element root = doc.getRootElement();

      List ls = root.getChildren();//注意此处取出的是root节点下面的一层的Element集合

      for (Iterator iter = ls.iterator(); iter.hasNext(); ) {

        Element el = (Element) iter.next();

        if(el.getName().equals("to")){

         System.out.println(el.getText());

        }

      }

    }

    catch (IOException ex) {

      ex.printStackTrace();

    }

    catch (JDOMException ex) {

      ex.printStackTrace();

    }

}

(3)DOM的document和JDOM的Document之间的相互�{换��用方法，��单！

DOMBuilder builder = new DOMBuilder();

org.jdom.Document jdomDocument = builder.build(domDocument);

DOMOutputter converter = new DOMOutputter();// work with the JDOM document…

org.w3c.dom.Document domDocument = converter.output(jdomDocument);

// work with the DOM document…

2.XML文档输出

XMLOutPutter�c�：

JDOM的输出非常灵�z?支持很多�U�io格式以及风格的输�?/p>
Document doc = new Document(...);

XMLOutputter outp = new XMLOutputter();

outp.output(doc, fileOutputStream); // Raw output

outp.setTextTrim(true); // Compressed output

outp.output(doc, socket.getOutputStream());

outp.setIndent(" ");// Pretty output

outp.setNewlines(true);

outp.output(doc, System.out);

详细请参阅最新的JDOM API手册

3.Element �c�：

(1)��览Element�?/p>
Element root = doc.getRootElement();//获得根元素element

List allChildren = root.getChildren();// 获得所有子元素的一个list

List namedChildren = root.getChildren("name");// 获得指定名称子元素的list

Element child = root.getChild("name");//获得指定名称的第一个子元素

JDOM�l�了我们很多很灵�zȝ��使用�Ҏ��来管理子元素�Q�这里的List是java.util.List�Q?/p>
List allChildren = root.getChildren();

allChildren.remove(3); // 删除�W�四个子元素

allChildren.removeAll(root.getChildren("jack"));// 删除�?#8220;jack”的子元素

root.removeChildren("jack"); // 便捷写法

allChildren.add(new Element("jane"));// 加入

root.addContent(new Element("jane")); // 便捷写法

allChildren.add(0, new Element("first"));

(2)�U�d��Elements:

在JDOM里很��?/p>
Element movable = new Element("movable");

parent1.addContent(movable); // place

parent1.removeContent(movable); // remove

parent2.addContent(movable); // add

在Dom�?/p>
Element movable = doc1.createElement("movable");

parent1.appendChild(movable); // place

parent1.removeChild(movable); // remove

parent2.appendChild(movable); // 出错!

补充�Q�纠错�?/p>
JDOM的Element构造函敎ͼ�以及它的其他函数�Q�会��查element是否合法�?/p>
而它的add/remove�Ҏ��会检查树�l�构�Q�检查内容如下：

1.在�Q何树中是否有回环节点

2.是否只有一个根节点

3.是否有一致的命名�I�间�Q�Namespaces�Q?

(3)Element的text内容��d��

A cool demo

// The text is directly available

// Returns "\n A cool demo\n"

String desc = element.getText();

// There's a convenient shortcut

// Returns "A cool demo"

String desc = element.getTextTrim();

(4)Elment内容修改

element.setText("A new description");

3.可正��解释特�D�字�W?/p>
element.setText(" content");

4.CDATA的数据写入、读�?/p>
element.addContent(new CDATA(" content"));

String noDifference = element.getText();

混合内容

element可能包含很多�U�内容，比如�?/p>
Some text
Some child element

取table的子元素tr

String text = table.getTextTrim();

Element tr = table.getChild("tr");

也可使用另外一个比较简单的�Ҏ��

List mixedCo = table.getContent();

Iterator itr = mixedCo.iterator();

while (itr.hasNext()) {

Object o = i.next();

if (o instanceof Comment) {...}

// �q�里可以写成Comment, Element, Text, CDATA,ProcessingInstruction, 或者是EntityRef的类�?/p>
}

// 现在�U�除Comment,注意�q�里游标应�ؓ1。这是由于回车键也被解析成Text�cȝ��~�故,所以Comment��应�?�?/p>
mixedCo.remove(1);

4.Attribute�c?/p>

String width = table.getAttributeValue("width");//获得attribute

int border = table.getAttribute("width").getIntValue();

table.setAttribute("vspace", "0");//讄��attribute

table.removeAttribute("vspace");// 删除一个或全部attribute

table.getAttributes().clear();

5.处理指��o(Processing Instructions)操作

一个Pls的例�?/p>

          |        |

          |        |

        目标     数据

处理目标名称(Target)

String target = pi.getTarget();

获得所有数据（data�Q�，在目标（target�Q�以后的所有数据都会被�q�回�?/p>
String data = pi.getData();

String type = pi.getValue("type");获得指定属性的数据

List ls = pi.getNames();获得所有属性的名称

6.命名�I�间操作

xmlns:xhtml="http://www.w3.org/1999/xhtml">

Home Page

Namespace xhtml = Namespace.getNamespace("xhtml", "http://www.w3.org/1999/xhtml");

List kids = html.getChildren("title", xhtml);

Element kid = html.getChild("title", xhtml);

kid.addContent(new Element("table", xhtml));

7.XSLT格式转换

使用以下函数可对XSLT转换

最后如果你需要��用w3c的Document则需要�{换一下�?/p>
public static Document transform(String stylesheet�Q�Document in)

                                        throws JDOMException {

     try {

       Transformer transformer = TransformerFactory.newInstance()

                             .newTransformer(new StreamSource(stylesheet));

       JDOMResult out = new JDOMResult();

       transformer.transform(new JDOMSource(in), out);

       return out.getDeocument();

     }

     catch (TransformerException e) {

       throw new JDOMException("XSLT Trandformation failed", e);

     }

   }

五、用�?

1、生成xml文档�Q?/p>

public class WriteXML{

    public void BuildXML() throws Exception {

        Element root,student,number,name,age;

        root = new Element("student-info"); //生成根元素：student-info

        student = new Element("student"); //生成元素�Q�student(number,name,age)

        number = new Element("number");

        name = new Element("name");

        age = new Element("age");

        Document doc = new Document(root); //��根元素植入文档doc�?/p>
        number.setText("001");

        name.setText("lnman");

        age.setText("24");

        student.addContent(number);

        student.addContent(name);

        student.addContent(age);

        root.addContent(student);

        Format format = Format.getCompactFormat();

        format.setEncoding("gb2312"); //讄��xml文�g的字�W��ؓgb2312

        format.setIndent("    "); //讄��xml文�g的羃�q��ؓ4个空�?/p>
        XMLOutputter XMLOut = new XMLOutputter(format);//元素后换行一层元素羃四格

        XMLOut.output(doc, new FileOutputStream("studentinfo.xml"));

}

    public static void main(String[] args) throws Exception {

        WriteXML w = new WriteXML();

        System.out.println("Now we build an XML document .....");

        w.BuildXML();

        System.out.println("finished!");

}

}

生成的xml文档为：



        001

        lnman

        24



创徏XML文档2�Q?/p>
public class CreateXML {

public void Create() {

   try {

    Document doc = new Document();

    ProcessingInstruction pi=new ProcessingInstruction("xml-stylesheet","type="text/xsl" href="test.xsl"");

    doc.addContent(pi);

    Namespace ns = Namespace.getNamespace("http://www.bromon.org" );

    Namespace ns2 = Namespace.getNamespace("other", "http://www.w3c.org" );

    Element root = new Element("根元�?, ns);

    root.addNamespaceDeclaration(ns2);

    doc.setRootElement(root);

    Element el1 = new Element("元素一");

    el1.setAttribute("属�?, "属性一");

    Text text1=new Text("元素�?);

             Element em = new Element("元素�?).addContent("�W�二个元�?);

    el1.addContent(text1);

             el1.addContent(em);

             Element el2 = new Element("元素�?).addContent("�W�三个元�?);

             root.addContent(el1);

             root.addContent(el2);

             //�~�进四个�I�格,自动换行,gb2312�~�码

             XMLOutputter outputter = new XMLOutputter(" ", true,"GB2312");

             outputter.output(doc, new FileWriter("test.xml"));

         }catch(Exception e) {

          System.out.println(e);

         }

     }

     public static void main(String args[]) {

      new CreateXML().Create();

     }

}

2、读取xml文档的例子：

import org.jdom.output.*;

import org.jdom.input.*;

import org.jdom.*;

import java.io.*;

import java.util.*;

public class ReadXML{

    public static void main(String[] args) throws Exception {

        SAXBuilder builder = new SAXBuilder();

        Document read_doc = builder.build("studentinfo.xml");

        Element stu = read_doc.getRootElement();

        List list = stu.getChildren("student");

        for(int i = 0;i < list.size();i++) {

            Element e = (Element)list.get(i);

            String str_number = e.getChildText("number");

            String str_name = e.getChildText("name");

            String str_age = e.getChildText("age");

            System.out.println("---------STUDENT--------------");

            System.out.println("NUMBER:" + str_number);

            System.out.println("NAME:" + str_name);

            System.out.println("AGE:" + str_age);

            System.out.println("------------------------------");

            System.out.println();

        }

       }

}

3、DTD验证的：

public class XMLWithDTD {

public void validate() {

   try {

    SAXBuilder builder = new SAXBuilder(true);

    builder.setFeature("http://xml.org/sax/features/validation";,true);

    Document doc = builder.build(new FileReader("author.xml"));

    System.out.println("搞掂");

    XMLOutputter outputter = new XMLOutputter();

    outputter.output(doc, System.out);

   }catch(Exception e) {

    System.out.println(e);

   }

}

public static void main(String args[]) {

   new XMLWithDTD().validate();

}

}

　　需要说明的是，�q�个�E�序没有指明使用哪个DTD文�g。DTD文�g的位�|�是在XML中指定的�Q��? 且DTD不支持命名空��_��一个XML只能引用一个DTD�Q�所以程序直接读取XML中指定的DTD�Q�程序本�w�不用指定。不�q�这样一来，好象��只能��用外部式的DTD引用方式了？高�h指点�?/p>

4、XML Schema验证的：

public class XMLWithSchema {

String xml="test.xml";

String schema="test-schema.xml";

public void validate() {

   try {

    SAXBuilder builder = new SAXBuilder(true);

    //指定�U�束方式为XML schema

    builder.setFeature("http://apache.org/xml/features/validation/schema";, true);

    //导入schema文�g

builder.setProperty("http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation";,schema);

    Document doc = builder.build(new FileReader(xml));

    System.out.println("搞掂");

    XMLOutputter outputter = new XMLOutputter();

    outputter.output(doc, System.out);

   }catch(Exception e) {

    System.out.println("验证��p�|:"+e);

   }

}

}

上面的程序就指出了要引入的XML Schema文�g的位�|��?/p>

�pȝ��默认输出是UTF-8�Q�这有可能导致出��Cؕ码�?/p>
5、Xpath例子�Q?/p>
JDOM的关于XPATH的api在org.jdom.xpath�q�个包里。这个包下，有一个抽象类 XPath.java和实现类JaxenXPath.java�Q?使用时先用XPath�cȝ��静态方法newInstance(String xpath)得到XPath对象�Q�然后调用它的selectNodes(Object context)�Ҏ��或selectSingleNode(Object context)�Ҏ��Q�前者根据xpath语句�q�回一�l�节�?List对象)�Q�后者根据一个xpath语句�q�回�W�合条�g的第一个节�?Object�c? �?。请看jdom-1.0自带的范例程序：

     它分析在web.xml文�g中的注册的servlet的个数及参数个数�Q��ƈ输出角色名�?

web.xml文�g�Q?



        snoop

        SnoopServlet





        file

        ViewFile



            initial

            1000

            The initial value for the counter







        mv

        *.wm







      manager

      director

      president



处理�E�序�Q?

import java.io.*;

import java.util.*;

public class XPathReader {

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

        if (args.length != 1) {

            System.err.println("Usage: java XPathReader web.xml");

            return;

        }

        String filename = args[0];//从命令行输入web.xml

        PrintStream out = System.out;

        SAXBuilder builder = new SAXBuilder();

        Document doc = builder.build(new File(filename));//得到Document对象

        // Print servlet information

        XPath servletPath = XPath.newInstance("http://servlet");//,选择��L��路径下servlet元素

        List servlets = servletPath.selectNodes(doc);//�q�回所有的servlet元素�?/p>
        out.println("This WAR has "+ servlets.size() +" registered servlets:");

        Iterator i = servlets.iterator();

        while (i.hasNext()) {//输出servlet信息

            Element servlet = (Element) i.next();

            out.print("\t" + servlet.getChild("servlet-name")

                                    .getTextTrim() +

                      " for " + servlet.getChild("servlet-class")

                                       .getTextTrim());

            List initParams = servlet.getChildren("init-param");

            out.println(" (it has " + initParams.size() + " init params)");

        }

        // Print security role information

        XPath rolePath = XPath.newInstance("http://security-role/role-name/text()");

        List roleNames = rolePath.selectNodes(doc);//得到所有的角色�?

        if (roleNames.size() == 0) {

            out.println("This WAR contains no roles");

        } else {

            out.println("This WAR contains " + roleNames.size() + " roles:");

            i = roleNames.iterator();

            while (i.hasNext()) {//输出角色�?

                out.println("\t" + ((Text)i.next()).getTextTrim());

            }

        }

    }

}

输出�l�果:

C:\java>java   XPathReader web.xml

This WAR has 2 registered servlets:

        snoop for SnoopServlet (it has 0 init params)

        file for ViewFile (it has 1 init params)

This WAR contains 3 roles:

        manager

        director

        president

6、数据输入要用到XML文档要通过org.jdom.input包，反过来需要org.jdom.output。如前面所��_��x��看API文档��p��够��用�?

我们的例子读入XML文�gexampleA.xml�Q�加入一条处理指令，修改�W�一本书的�h格和作者，�q�添加一条属性，然后写入文�gexampleB.xml�Q?

//exampleA.xml

Java�~�程入门

张三

2002-6-6

35.0

XML在Java中的应用

李四

2002-9-16

92.0

//testJDOM.java

import org.jdom.*;

import org.jdom.output.*;

import org.jdom.input.*;

import java.io.*;

public class TestJDOM{

public static void main(String args[])throws Exception{

SAXBuilder sb = new SAXBuilder();

//从文件构造一个Document�Q�因为XML文�g中已�l�指定了�~�码�Q�所以这里不必了

Document doc = sb.build(new FileInputStream("exampleA.xml"));

ProcessingInstruction pi = new ProcessingInstruction//加入一条处理指�?

("xml-stylesheet","href=\"bookList.html.xsl\" type=\"text/xsl\"");

doc.addContent(pi);

Element root = doc.getRootElement(); //得到根元�?

java.util.List books = root.getChildren(); //得到根元素所有子元素的集�?

Element book = (Element)books.get(0); //得到�W�一个book元素

//为第一本书��d��一条属�?

Attribute a = new Attribute("hot","true");

book.setAttribute(a);

Element author = book.getChild("author"); //得到指定的字元素

author.setText("王五"); //��作者改为王�?

//�?Text t = new Text("王五");book.addContent(t);

Element price = book.getChild("price"); //得到指定的字元素

//修改��h��Q�比较郁��L��是我们必��自��p�{换数据类型，而这正是JAXB的优�?

author.setText(Float.toString(50.0f));

String indent = " ";

boolean newLines = true;

XMLOutputter outp = new XMLOutputter(indent,newLines,"GBK");

outp.output(doc, new FileOutputStream("exampleB.xml"));

}

};

执行�l�果exampleB.xml�Q?

Java�~�程入门

50.0

2002-6-6

35.0

XML在Java中的应用

李四

2002-9-16

92.0

在默认情况下�Q�JDOM的Element�cȝ��getText()�q�类的方法不会过滤空白字�W�，如果你需要过滤，用setTextTrim() �?/p>

flustar 2007-04-29 14:08 发表评论