SAXReader reader = new SAXReader();???
Document doc = reader.read(…);???
List childNodes = doc.selectNodes(“//Config/Child/ChildNode”);???
for(Object obj:childNodes) {???
????? Node childNode = (Node)obj;???
????? String name = childNode.valueOf(“@name”);???
????? String text = childNode.getText();???
}?????
一.Document对象相关??
????? 1.读取XML文件,获得document对象.??
??????????? SAXReader reader = new SAXReader();??
??????????? Document?? document = reader.read(new File(“input.xml”));??
?????? 2.解析XML形式的文本,得到document对象.??
??????????? String text = “<members></members>”;??
??????????? Document document = DocumentHelper.parseText(text);??
????? 3.主动创建document对象.??
??????????? Document document = DocumentHelper.createDocument();??
??????????? Element root = document.addElement(“members”);// 创建根节点??
二.节点相关??
????? 1.获取文档的根节点.??
??????????? Element rootElm = document.getRootElement();??
????? 2.取得某节点的单个子节点.??
??????????? Element memberElm=root.element(“member”);// “member”是节点名??
????? 3.取得节点的文字??
??????????? String text=memberElm.getText();也可以用:??
??????????? String text=root.elementText(“name”);这个是取得根节点下的name字节点的文字.??
????? 4.取得某节点下名为”member”的所有字节点并进行遍历.??
??????????? List nodes = rootElm.elements(“member”);??
??????????? for (Iterator it = nodes.iterator(); it.hasNext();) {??
????????????????? Element elm = (Element) it.next();??
????????????????? // do something??
??????????? }??
????? 5.对某节点下的所有子节点进行遍历.??
???????????? for(Iterator it=root.elementIterator();it.hasNext();){??
????????????????? Element element = (Element) it.next();??
?????????????????? // do something??
??????????? }??
????? 6.在某节点下添加子节点.??
??????????? Element ageElm = newMemberElm.addElement(“age”);??
????? 7.设置节点文字.??
??????????? ageElm.setText(“29”);??
????? 8.删除某节点.??
??????????? parentElm.remove(childElm);// childElm是待删除的节点,parentElm是其父节点??
????? 9.添加一个CDATA节点.??
??????????? Element contentElm = infoElm.addElement(“content”);??
??????????? contentElm.addCDATA(diary.getContent());??
三.属性相关.??
????? 1.取得某节点下的某属性??
??????????? Element root=document.getRootElement();??????
??????????? Attribute attribute=root.attribute(“size”);// 属性名name
????? 2.取得属性的文字??
??????????? // 也可以用
??????????? String text=attribute.getText();??
??????????? //? 这个是取得根节点下name字节点的属性firstname的值:?
??????????? String text2=root.element(“name”).attributeValue(“firstname”);
????? 3.遍历某节点的所有属性???
??????????? Element root=document.getRootElement();???????
??????????? for(Iterator it=root.attributeIterator();it.hasNext();){???
???????????????? Attribute attribute = (Attribute) it.next();???
???????????????? String text=attribute.getText();???
???????????????? System.out.println(text);???
??????????? }
????? 4.设置某节点的属性和文字.???
??????????? newMemberElm.addAttribute(“name”, “sitinspring”);???
????? 5.设置属性的文字??
?????????? Attribute attribute=root.attribute(“name”);???
?????????? attribute.setText(“sitinspring”);???
????? 6.删除某属性???
?????????? Attribute attribute=root.attribute(“size”);// 属性名name???
?????????? root.remove(attribute);???
四.将文档写入XML文件.???
?????
????? 1.文档中全为英文,不设置编码,直接写入的形式.???
??????????? XMLWriter writer = new XMLWriter(new FileWriter(“output.xml”));???
??????????? writer.write(document);???
??????????? writer.close();???
????? 2.文档中含有中文,设置编码格式写入的形式.???
??????????? OutputFormat format = OutputFormat.createPrettyPrint();???
??????????? format.setEncoding(“GBK”);??? // 指定XML编码???????????
??????????? XMLWriter writer = new XMLWriter(new FileWriter(“output.xml”),format);???????????????????
??????????? writer.write(document);???
??????????? writer.close();???
五.字符串与XML的转换???
????? 1.将字符串转化为XML???
??????????? String text = “<members> <member>sitinspring</member> </members>”;???
??????????? Document document = DocumentHelper.parseText(text);???
????? 2.将文档或节点的XML转化为字符串.???
??????????? SAXReader reader = new SAXReader();???
??????????? Document?? document = reader.read(new File(“input.xml”));???????????????
??????????? Element root=document.getRootElement();???????????????????
??????????? String docXmlText=document.asXML();???
??????????? String rootXmlText=root.asXML();???
??????????? Element memberElm=root.element(“member”);???
??????????? String memberXmlText=memberElm.asXML();??????
????? {???? dom4j API 包含一个解析 XML 文档的工具。本文中将使用这个解析器创建一个示例 XML 文档。清单 1 显示了这个示例 XML 文档，catalog.xml。?? }?
?????
????? 清单 1. 示例 XML 文档（catalog.xml）????
??????????? <?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>?????
???????????
??????????? 然后使用同一个解析器修改 catalog.xml，清单 2 是修改后的 XML 文档，catalog-modified.xml。???
?????
????? 清单 2. 修改后的 XML 文档（catalog-modified.xml）????
??????????? <?xml version=”1.0″ encoding=”UTF-8″?>????
??????????? <catalog>????
????????????????? <!–An XML catalog–>????
????????????????? <?target instruction?>???
????????????????? <journal title=”XML Zone” publisher=”IBM developerWorks”>????
??????????????????????? <article level=”Introductory” date=”October-2002″>???
????????????????????????????? <title>Create flexible and extensible XML schemas</title>??
????????????????????????????? <author>????
??????????????????????????????????? <firstname>Ayesha</firstname>????
??????????????????????????????????? <lastname>Malik</lastname>????
?????????????????????????????? </author>????
??????????????????????? </article>
????????????????? </journal>
??????????? </catalog>???
????????????????? 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。???
????? 本文包括以下几个部分：???
预先设置????
创建文档????
修改文档????
????? 预先设置??
???????????? 这个解析器可以从 http://dom4j.org 获取。通过设置使 dom4j-1.4/dom4j-full.jar 能够在 classpath 中访问，该文件中包括 dom4j 类、XPath 引擎以及 SAX 和 DOM 接口。如果已经使用了 JAXP 解析器中包含的 SAX 和 DOM 接口，向 classpath 中增加 dom4j-1.4/dom4j.jar 。 dom4j.jar 包括 dom4j 类和 XPath 引擎，但是不含 SAX 与 DOM 接口。???
????? 创建文档???
??????????? 本节讨论使用 dom4j API 创建 XML 文档的过程，并创建示例 XML 文档 catalog.xml。???
???????????
??????????? 使用 import 语句导入 dom4j API 类：???
???????????
??????????? import org.dom4j.Document;???
??????????? import org.dom4j.DocumentHelper;???
??????????? import org.dom4j.Element;????
??????????? 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”);????
???????????
??????????? 向 article 元素中添加 journal 元素。???
??????????? Element articleElement=journalElement.addElement(“article”);????
??????????? 为 article 元素增加 level 和 date 属性。????
??????????? articleElement.addAttribute(“level”, “Intermediate”);???
??????????? articleElement.addAttribute(“date”, “December-2001”);????
??????????? 向 article 元素中增加 title 元素。????
??????????? Element titleElement=articleElement.addElement(“title”);????
??????????? 使用 setText() 方法设置 article 元素的文本。????
??????????? titleElement.setText(“Java configuration with XML Schema”);????
??????????? 在 article 元素中增加 author 元素。????
??????????? Element authorElement=articleElement.addElement(“author”);????
??????????? 在 author 元素中增加 firstname 元素并设置该元素的文本。????
??????????? Element? firstNameElement=authorElement.addElement(“firstname”);???
??????????? firstNameElement.setText(“Marcello”);????
??????????? 在 author 元素中增加 lastname 元素并设置该元素的文本。???
??????????? Element lastNameElement=authorElement.addElement(“lastname”);???
??????????? lastNameElement.setText(“Vitaletti”);????
??????????? 可以使用 addDocType() 方法添加文档类型说明。???
??????????? document.addDocType(“catalog”, null,”file://c:/Dtds/catalog.dtd“);????
??????????? 这样就向 XML 文档中增加文档类型说明：?
??????????? <!DOCTYPE catalog SYSTEM “file://c:/Dtds/catalog.dtd“>????
?????
??????????? 如果文档要使用文档类型定义（DTD）文档验证则必须有 Doctype。???
?????
??????????? XML 声明 <?xml version=”1.0″ encoding=”UTF-8”?> 自动添加到 XML 文档中。????
???????????
??????????? 清单 3 所示的例子程序 XmlDom4J.java 用于创建 XML 文档 catalog.xml。???
??????????? 清单 3. 生成 XML 文档 catalog.xml 的程序（XmlDom4J.java）??????????
??????????? import org.dom4j.Document;???
??????????? import org.dom4j.DocumentHelper;???
??????????? import org.dom4j.Element;???
??????????? import org.dom4j.io.XMLWriter;???
??????????? import java.io.*;???
??????????? public class XmlDom4J{???
????????????????? public void generateDocument(){???
??????????????????????? Document document = DocumentHelper.createDocument();???
??????????????????????? Element catalogElement = document.addElement(“catalog”);???
??????????????????????? catalogElement.addComment(“An XML Catalog”);???
??????????????????????? catalogElement.addProcessingInstruction(“target”,”text”);???
??????????????????????? Element journalElement =? catalogElement.addElement(“journal”);???
??????????????????????? 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”);
??????????????????????? document.addDocType(“catalog”,? null,”file://c:/Dtds/catalog.dtd“);
??????????????????????? try{??
????????????????????????????? XMLWriter output = new XMLWriter(new FileWriter( new File(“c:/catalog/catalog.xml”) ));???
????????????????????????????? output.write( document );???
????????????????????????????? output.close();???
??????????????????????? }catch(IOException e){
????????????????????????????? System.out.println(e.getMessage());
??????????????????????? }???
????????????????? }???
????????????????? public static void main(String[] argv){???
??????????????????????? XmlDom4J dom4j=new XmlDom4J();???
??????????????????????? dom4j.generateDocument();???
????????????????? }
??????????? }???
??????????? 这一节讨论了创建 XML 文档的过程，下一节将介绍使用 dom4j API 修改这里创建的 XML 文档。????
???????????
????? 修改文档???
???????????
????????????????? 这一节说明如何使用 dom4j API 修改示例 XML 文档 catalog.xml。???
????? 使用 SAXReader 解析 XML 文档 catalog.xml：???
??????????? SAXReader saxReader = new SAXReader();??
??????????? Document document = saxReader.read(inputXml);????
?????
????? SAXReader 包含在 org.dom4j.io 包中。????
??????????? inputXml 是从 c:/catalog/catalog.xml 创建的 java.io.File。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”);????
????????????????? }????
??????????? 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”);???
??????????????????????? }
????????????????? }????
??????? 通过和 title 元素类似的过程修改 author 元素。????
????? 清单 4 所示的示例程序 Dom4JParser.java 用于把 catalog.xml 文档修改成 catalog-modified.xml 文档。???
????? 清单 4. 用于修改 catalog.xml 的程序（Dom4Jparser.java）????
?????
??????????? import org.dom4j.Document;???
??????????? import org.dom4j.Element;???
??????????? import org.dom4j.Attribute;???
??????????? import java.util.List;???
??????????? import java.util.Iterator;???
??????????? import org.dom4j.io.XMLWriter;???
??????????? import java.io.*;???
??????????? import org.dom4j.DocumentException;???
??????????? import org.dom4j.io.SAXReader;????
??????????? public class Dom4JParser{???
????????????????? public void modifyDocument(File inputXml){???
????????????????? try{???
??????????????????????? SAXReader saxReader = new SAXReader();???
??????????????????????? Document document = saxReader.read(inputXml);???
??????????????????????? 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”);???
??????????????????????? }???
??????????????????????? 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”);???
??????????????????????????????????? }?
????????????????????????????? }???
????????????????????????????? XMLWriter output = new XMLWriter( new FileWriter( new File(“c:/catalog/catalog-modified.xml”) ));???
????????????????????????????? output.write( document );
????????????????????????????? output.close();???
??????????????????????? } catch(DocumentException e) {???
????????????????????????????? System.out.println(e.getMessage());???
??????????????????????? } catch(IOException e){??
????????????????????????????? System.out.println(e.getMessage());???
??????????????????????? }???
????????????????? }???
?????????????????
????????????????? public static void main(String[] argv){???
??????????????????????? Dom4JParser dom4jParser=new Dom4JParser();???
??????????????????????? dom4jParser.modifyDocument(new File(“c:/catalog/catalog.xml”));???
????????????????? }???
??????????? }