dom4j解析XML

  dom4j 是一种解析 XML 文档的开放源代码 XML 框架,与 W3C DOM API 相比,使用 dom4j 所包含的解析器的好处是 dom4j 拥有本地的 XPath 支持.DOM 解析器不支持使用 XPath 选择节点.

  该解析器可以从 http://dom4j.org/ 获取.

java 代码

java 代码

package com.nikee.dom4j;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import java.io.*;

public class XmlDom4J{
 public void generateDocument(){
  //使用 DocumentHelper 类创建一个文档实例。 DocumentHelper 是生成 XML 文档节点的 dom4j API 工厂类
  Document document = DocumentHelper.createDocument();

  //使用 addElement()方法创建根元素catalog , addElement()用于向 XML 文档中增加元素
  Element catalogElement = document.addElement("catalog");

  //在 catalog 元素中使用 addComment() 方法添加注释"An XML catalog"
  catalogElement.addComment("An XML Catalog");

  //在 catalog 元素中使用 addProcessingInstruction() 方法增加一个处理指令
  catalogElement.addProcessingInstruction("target","text");

  //在 catalog 元素中使用 addElement() 方法增加 journal 元素
  Element journalElement = catalogElement.addElement("journal");
  //使用 addAttribute() 方法向 journal 元素添加 title 和 publisher 属性
  journalElement.addAttribute("title", "XML Zone");
  journalElement.addAttribute("publisher", "IBM developerWorks");


  Element articleElement=journalElement.addElement("article");
  articleElement.addAttribute("level", "Intermediate");
  articleElement.addAttribute("date", "December-2001");

  Element titleElement=articleElement.addElement("title");
  titleElement.setText("Java configuration with XML Schema");

  Element authorElement=articleElement.addElement("author");
  Element firstNameElement=authorElement.addElement("firstname");
  firstNameElement.setText("Marcello");
  Element lastNameElement=authorElement.addElement("lastname");
  lastNameElement.setText("Vitaletti");

  //可以使用 addDocType() 方法添加文档类型说明
  //这样就向 XML 文档中增加文档类型说明：
  document.addDocType("catalog","nikee","file://c:/Dtds/catalog.dtd");
  try{
   //XMLWriter output = new XMLWriter(new FileWriter( new File("D:/eclipse3.2/workspace/WebServices/src/com/nikee/dom4j/catalog.xml")));
    FileOutputStream fos=new FileOutputStream("D:/eclipse3.2/workspace/WebServices/src/com/nikee/dom4j/catalog.xml");
       OutputFormat of=new OutputFormat("    ", true);
       XMLWriter xw=new XMLWriter(fos, of);
       xw.write( document );
       xw.close();
  }
  catch(IOException e)
  {
   System.out.println(e.getMessage());
  }
 }

 public static void main(String[] argv){
  XmlDom4J dom4j=new XmlDom4J();
  dom4j.generateDocument();
 }
}

xml 代码

xml 代码

<!--sp-->xml version="1.0" encoding="UTF-8"?>
<!--CTYPE catalog PUBLIC "nikee" "file://c:/Dtds/catalog.dtd"</sp-->>

 <catalog>
    <!--An XML Catalog--><!--sp-->target text?>

    <journal title="XML Zone" publisher="IBM developerWorks">
     <article level="Intermediate" date="December-2001">
         <title>Java configuration with XML Schematitle>
         <author>
             <firstname>Marcellofirstname>
             <lastname>Vitalettilastname>
         author>
     article>
    journal>
 catalog>

XmlDom4J.java 用于创建 XML 文档 catalog.xml

java 代码

java 代码

package com.nikee.dom4j;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.Attribute;
import java.util.List;
import java.util.Iterator;

import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import java.io.*;

import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;

public class Dom4Jparser{
    public Dom4Jparser(){
        //construction
    }

    public void modifyDocument(File inputXml){
        try{
            //使用 SAXReader 解析 XML 文档 catalog.xml
            SAXReader saxReader = new SAXReader();
            Document document = saxReader.read(inputXml);

            //使用 XPath 表达式从 article 元素中获得 level 节点列表。如果 level 属性值是"Intermediate"则改为"Introductory"
            List list = document.selectNodes("//article/@level");
            Iterator iter=list.iterator();
            while(iter.hasNext()){
                Attribute attribute=(Attribute)iter.next();
                if(attribute.getValue().equals("Intermediate"))
                    attribute.setValue("Introductory");
            }

            list = document.selectNodes("//article/@date" );
            iter=list.iterator();
            while(iter.hasNext()){
                Attribute attribute=(Attribute)iter.next();
                if(attribute.getValue().equals("December-2001"))
                    attribute.setValue("October-2002");
            }

            //获取 article 元素列表，从 article 元素中的 title 元素得到一个迭代器，并修改 title 元素的文本
            list = document.selectNodes("//article" );
            iter=list.iterator();
            while(iter.hasNext()){
                Element element=(Element)iter.next();
                Iterator iterator=element.elementIterator("title");
                while(iterator.hasNext()){
                    Element titleElement=(Element)iterator.next();
                    if(titleElement.getText().equals("Java configuration with XML Schema"))
                        titleElement.setText("Create flexible and extensible XML schema");
                }
            }


            list = document.selectNodes("//article/author" );
            iter=list.iterator();
            while(iter.hasNext()){
                Element element=(Element)iter.next();
                Iterator iterator=element.elementIterator("firstname");
                while(iterator.hasNext()){
                    Element firstNameElement=(Element)iterator.next();
                    if(firstNameElement.getText().equals("Marcello"))
                        firstNameElement.setText("Ayesha");
                }
            }

            list = document.selectNodes("//article/author" );
            iter=list.iterator();
            while(iter.hasNext()){
                Element element=(Element)iter.next();
                Iterator iterator=element.elementIterator("lastname");
                while(iterator.hasNext()){
                    Element lastNameElement=(Element)iterator.next();
                    if(lastNameElement.getText().equals("Vitaletti"))
                        lastNameElement.setText("Malik");
                }
            }

            FileOutputStream fos=new FileOutputStream("D:/eclipse3.2/workspace/WebServices/src/com/nikee/dom4j/catalog-modified.xml");
            OutputFormat of=new OutputFormat("   ",true);
            XMLWriter xw=new XMLWriter(fos, of);
            xw.write( document );
            xw.close();
        }
        catch(DocumentException e)
        {
            e.printStackTrace();
        }
        catch(IOException e){
            e.printStackTrace();
        }
    }

    public static void main(String argv[]){
        Dom4Jparser dom4jParser=new Dom4Jparser();
        dom4jParser.modifyDocument(new File("D:/eclipse3.2/workspace/WebServices/src/com/nikee/dom4j/catalog.xml"));
    }
}

xml 代码

xml 代码

<!--sp-->xml version="1.0" encoding="UTF-8"?>

<!--<!DOCTYPE catalog PUBLIC "nikee" "file://c:/Dtds/catalog.dtd">-->
<catalog>
<!--An XML Catalog--><!--sp-->target text?>
 <journal title="XML Zone" publisher="IBM developerWorks">
   <article level="Introductory" date="October-2002">
      <title>Create flexible and extensible XML schematitle>
      <author>
         <firstname>Ayeshafirstname>
         <lastname>Maliklastname>
      author>
   article>
 journal>
catalog>

Dom4Jparser.java用于修改 XML 文档 catalog.xml为catalog-modified.xml

问题总结:

1.当catalog.xml有<!--CTYPE catalog PUBLIC "nikee" "file://c:/Dtds/catalog.dt-->这一句,Dom4Jparser.java修改 XML 文档 catalog.xml为catalog-modified.xml时,发生异常org.dom4j.DocumentException: c Nested exception: c.

原因:我自己没有此file://c:/Dtds/catalog.dtd.

解决办法:删掉此行.

2.除了加入dom4j.jar包外,必须加入jaxen.jar包,否则会发生异常.jaxen包可在http://jaxen.org/下载.