Dom4j 操作XML

Dom4j也可以很方便完成XML文档的创建、元素的修改、文档的查询遍历等，但dom4j稍比jdom复杂一点，不过在大片文档的情况下dom4j的性能要不jdom好。

 

#  准备

首先，提供相关的jar包

Dom4jjar包下载：

http://sourceforge.net/projects/dom4j/files/dom4j-2.0.0-ALPHA-2/

jaxenjar下载：

http://repo1.maven.org/maven2/jaxen/jaxen/1.1.1/jaxen-1.1.1.jar

和dom4j依赖或相关的jar：

http://dom4j.sourceforge.net/dependencies.html

Junit-jar下载：

http://ebr.springsource.com/repository/app/bundle/version/download?name=com.springsource.org.junit&version=4.8.1&type=binary

 

其次，准备测试案例的部分代码：

package com.hoo.test;import java.io.File;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.Node;import org.dom4j.QName;import org.dom4j.dom.DOMAttribute;import org.dom4j.io.SAXReader;import org.dom4j.tree.BaseElement;import org.junit.After;import org.junit.Before;import org.junit.Test;/** * <b>function:</b> 使用Dom4j操作XML * @author hoojo * @createDate 2011-8-5 下午06:15:40 * @file DocumentTest.java * @package com.hoo.test * @project Dom4jTest * @blog http://blog.csdn.net/IBM_hoojo * @email [e-mail] * @version 1.0 */public class DocumentTest {private SAXReader reader = null;@Beforepublic void init() {reader = new SAXReader();}@Afterpublic void destory() {reader = null;System.gc();}public void fail(Object o) {if (o != null)System.out.println(o);}}

 

#  创建一篇XML文档

文档格式如下：

<?xml version="1.0" encoding="UTF-8"?> <catalog> <!--An XML Catalog--> <?target instruction?><journal title="XML Zone" publisher="IBM developerWorks">  <article level="Intermediate" date="December-2001"> <title>Java configuration with XML Schema</title>  <author>      <firstname>Marcello</firstname>      <lastname>Vitaletti</lastname>  </author>   </article></journal> </catalog>

 

创建文档代码如下：

/** * <b>function:</b>创建文档 * @author hoojo * @createDate 2011-8-5 下午06:18:18 */@Testpublic void createDocument() {//创建一篇文档Document doc = DocumentHelper.createDocument();//添加一个元素Element root = doc.addElement("catalog");//为root元素添加注释root.addComment("An XML Catalog");//添加标记root.addProcessingInstruction("target", "instruction");//创建元素Element journalEl = new BaseElement("journal");//添加属性journalEl.addAttribute("title", "XML Zone");journalEl.addAttribute("publisher", "IBM developerWorks");root.add(journalEl);//添加元素Element articleEl = journalEl.addElement("article");articleEl.addAttribute("level", "Intermediate");articleEl.addAttribute("date", "December-2001");Element titleEl = articleEl.addElement("title");//设置文本内容titleEl.setText("Java configuration with XML Schema");//titleEl.addText("Java configuration with XML Schema");Element authorEl = articleEl.addElement("author");authorEl.addElement("firstname").setText("Marcello");authorEl.addElement("lastname").addText("Vitaletti");//可以使用 addDocType() 方法添加文档类型说明。 doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd"); fail(doc.getRootElement().getName());//将xml转换成文本fail(doc.asXML());//写入到文件/*XMLWriter output;try {output = new XMLWriter(new FileWriter(new File("file/catalog.xml")));output.write(doc);output.close();} catch (IOException e) {e.printStackTrace();}*/}

*  DocumentHelper是一个文档助手类（工具类），它可以完成文档、元素、文本、属性、注释、CDATA、Namespace、XPath的创建，以及利用XPath完成文档的遍历和将文本转换成Document；

parseText完成将xml字符串转换成Doc的功能

Document doc = DocumentHelper.parseText("<root></root>");

 

createDocument创建一个文档

Document doc = DocumentHelper.createDocument();

如果带参数就会创建一个带有根元素的文档

createElement创建一个元素

Element el = DocumentHelper.createElement("el");

 

*  Document的addElement方法可以给当前文档添加一个子元素

Element root = doc.addElement("catalog");

 

*  addComment方法可以添加一段注释

root.addComment("An XML Catalog");

为root元素添加一段注释

 

*  addProcessingInstruction添加一个标记

root.addProcessingInstruction("target", "instruction");

为root元素添加一个标记

 

*  newBaseElement可以创建一个元素

Element journalEl = new BaseElement("journal");

 

*  addAttribute添加属性

journalEl.addAttribute("title", "XML Zone");

 

*  add添加一个元素

root.add(journalEl);

将journalEl元素添加到root元素中

 

*  addElement添加一个元素，并返回当前元素

Element articleEl = journalEl.addElement("article");

给journalEl元素添加一个子元素article

 

*  setText、addText可以设置元素的文本

authorEl.addElement("firstname").setText("Marcello");

authorEl.addElement("lastname").addText("Vitaletti");

 

*  addDocType可以设置文档的DOCTYPE

doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd");

 

*  asXML可以将文档或元素转换成一段xml字符串

doc.asXML();

root.asXML();

 

*  XMLWriter类可以把文档写入到文件中

output = new XMLWriter(new FileWriter(new File("file/catalog.xml")));

output.write(doc);

output.close();

 

#  修改XML文档内容

/** * <b>function:</b> 修改XML内容 * @author hoojo * @createDate 2011-8-9 下午03:37:04 */@SuppressWarnings("unchecked")@Testpublic void modifyDoc() {try {Document doc = reader.read(new File("file/catalog.xml"));//修改属性内容List list = doc.selectNodes("//article/@level");Iterator<Attribute> iter = list.iterator();while (iter.hasNext()) {Attribute attr = iter.next();fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());if ("Intermediate".equals(attr.getValue())) {//修改属性值attr.setValue("Introductory");fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());}}list = doc.selectNodes("//article/@date");iter = list.iterator();while (iter.hasNext()) {Attribute attr = iter.next();fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());if ("December-2001".equals(attr.getValue())) {//修改属性值attr.setValue("December-2011");fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());}}//修改节点内容list = doc.selectNodes("//article");Iterator<Element> it = list.iterator();while (it.hasNext()) {Element el = it.next();fail(el.getName() + "#" + el.getText() + "#" + el.getStringValue());//修改title元素Iterator<Element> elIter = el.elementIterator("title");while(elIter.hasNext()) {Element titleEl = elIter.next();fail(titleEl.getName() + "#" + titleEl.getText() + "#" + titleEl.getStringValue());if ("Java configuration with XML Schema".equals(titleEl.getTextTrim())) {//修改元素文本值titleEl.setText("Modify the Java configuration with XML Schema");fail(titleEl.getName() + "#" + titleEl.getText() + "#" + titleEl.getStringValue());}}}//修改节点子元素内容list = doc.selectNodes("//article/author");it = list.iterator();while (it.hasNext()) {Element el = it.next();fail(el.getName() + "#" + el.getText() + "#" + el.getStringValue());List<Element> childs = el.elements();for (Element e : childs) {fail(e.getName() + "#" + e.getText() + "#" + e.getStringValue());if ("Marcello".equals(e.getTextTrim())) {e.setText("Ayesha");} else if ("Vitaletti".equals(e.getTextTrim())) {e.setText("Malik");} fail(e.getName() + "#" + e.getText() + "#" + e.getStringValue());}}//写入到文件/*XMLWriter output = new XMLWriter(new FileWriter(new File("file/catalog-modified.xml")));output.write(doc);output.close();*/} catch (DocumentException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}

*  reader.read(new File("file/catalog.xml"));读取指定xml文件内容到文档中；

*  selectNodes是XPath的查询方法，完成xml文档的查询，传递xpath路径。其使用方法可以参考jdom的xpath的使用方法：http://www.cnblogs.com/hoojo/archive/2011/08/11/2134638.html

*  getName获取元素标签名称、getValue、getText获取值、文本内容；

*  elementIterator("title");获取当前节点下所有的title元素，返回Iterator；

*  elements获取下面所有的子元素，返回的是一个集合List；

 

#  显示文档相关信息

private String format(int i) {String temp = "";while (i > 0) {temp += "--";i--;}return temp;}/** * <b>function:</b>递归显示文档内容 * @author hoojo * @createDate 2011-8-9 下午03:43:45 * @param i * @param els */private void print(int i, List<Element> els) {i++;for (Element el : els) {fail(format(i) + "##" + el.getName() + "#" + el.getTextTrim());if (el.hasContent()) {print(i, el.elements());} }}/** * <b>function:</b>显示文档相关信息 * @author hoojo * @createDate 2011-8-9 下午03:44:10 */@Testpublic void printInfo() {try {Document doc = reader.read(new File("file/catalog.xml"));fail("asXML: " + doc.asXML());fail(doc.asXPathResult(new BaseElement("article")));List<Node> list = doc.content();for (Node node : list) {fail("Node: " + node.getName() + "#" + node.getText() + "#" + node.getStringValue());}fail("-----------------------------");print(0, doc.getRootElement().elements());fail("getDocType: " + doc.getDocType());fail("getNodeTypeName: " + doc.getNodeTypeName());fail("getPath: " + doc.getRootElement().getPath());fail("getPath: " + doc.getRootElement().getPath(new BaseElement("journal")));fail("getUniquePath: " + doc.getRootElement().getUniquePath());fail("getXMLEncoding: " + doc.getXMLEncoding());fail("hasContent: " + doc.hasContent());fail("isReadOnly: " + doc.isReadOnly());fail("nodeCount: " + doc.nodeCount());fail("supportsParent: " + doc.supportsParent());} catch (DocumentException e) {e.printStackTrace();}fail("getEncoding: " + reader.getEncoding());fail("isIgnoreComments: " + reader.isIgnoreComments());fail("isMergeAdjacentText: " + reader.isMergeAdjacentText());fail("isStringInternEnabled: " + reader.isStringInternEnabled());fail("isStripWhitespaceText: " + reader.isStripWhitespaceText());fail("isValidating: " + reader.isValidating());}

 

#  删除文档内容

/** * <b>function:</b> 删除节点内容 * @author hoojo * @createDate 2011-8-9 下午03:47:44 */@Testpublic void removeNode() {try {Document doc = reader.read(new File("file/catalog-modified.xml"));fail("comment: " + doc.selectSingleNode("//comment()"));//删除注释doc.getRootElement().remove(doc.selectSingleNode("//comment()"));Element node = (Element) doc.selectSingleNode("//article");//删除属性node.remove(new DOMAttribute(QName.get("level"), "Introductory"));//删除元素 节点node.remove(doc.selectSingleNode("//title"));//只能删除下一级节点，不能超过一级；（需要在父元素的节点上删除子元素）Node lastNameNode = node.selectSingleNode("//lastname");lastNameNode.getParent().remove(lastNameNode);fail("Text: " + doc.selectObject("//*[text()='Ayesha']"));Element firstNameEl = (Element)doc.selectObject("//firstname");fail("Text: " + firstNameEl.selectSingleNode("text()"));//删除text文本//firstNameEl.remove(firstNameEl.selectSingleNode("text()"));//firstNameEl.remove(doc.selectSingleNode("//firstname/text()"));firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()"));//删除子元素author//node.remove(node.selectSingleNode("//author"));fail(doc.asXML());} catch (Exception e) {e.printStackTrace();}}

*  删除注释

doc.getRootElement().remove(doc.selectSingleNode("//comment()"));

删除root元素下面的注释

 

*  删除属性

node.remove(new DOMAttribute(QName.get("level"), "Introductory"));

删除node节点中的名称为level，其值为Introductory的属性

 

*  删除元素

node.remove(doc.selectSingleNode("//title"));

删除node节点下的title元素

 

*  删除文本

firstNameEl.remove(firstNameEl.selectSingleNode("text()"));

firstNameEl.remove(doc.selectSingleNode("//firstname/text()"));

firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()"));

删除firstNameEl的文本内容