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文中代码部分引用自DOM4J文档。
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Attribute
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Attribute定义了XML的属性
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Branch
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Branch为能够包含子节点的节点如XML元素(Element)和文档(Docuemnts)定义了一个公共的行为,
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CDATA
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CDATA 定义了XML CDATA 区域
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CharacterData
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CharacterData是一个标识借口,标识基于字符的节点。如CDATA,Comment, Text.
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Comment
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Comment 定义了XML注释的行为
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Document
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定义了XML文档
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DocumentType
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DocumentType 定义XML DOCTYPE声明
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Element
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Element定义XML 元素
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ElementHandler
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ElementHandler定义了 Element 对象的处理器
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ElementPath
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被
ElementHandler 使用,用于取得当前正在处理的路径层次信息
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Entity
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Entity定义 XML entity
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Node
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Node为所有的dom4j中XML节点定义了多态行为
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NodeFilter
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NodeFilter 定义了在dom4j节点中产生的一个滤镜或谓词的行为(predicate)
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ProcessingInstruction
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ProcessingInstruction 定义 XML 处理指令.
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Text
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Text 定义XML 文本节点.
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Visitor
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Visitor 用于实现Visitor模式.
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XPath
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XPath 在分析一个字符串后会提供一个XPath 表达式
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// 从文件读取XML,输入文件名,返回XML文档
public Document read(String fileName)
throws MalformedURLException, DocumentException {
SAXReader reader =
new SAXReader();
Document document = reader.read(
new File(fileName));
return document;
}
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public Element getRootElement(Document doc){
return doc.getRootElement();
}
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// 枚举所有子节点
for ( Iterator i = root.elementIterator(); i.hasNext(); ) {
Element element = (Element) i.next();
// do something
}
// 枚举名称为foo的节点
for ( Iterator i = root.elementIterator(foo); i.hasNext();) {
Element foo = (Element) i.next();
// do something
}
// 枚举属性
for ( Iterator i = root.attributeIterator(); i.hasNext(); ) {
Attribute attribute = (Attribute) i.next();
// do something
}
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public
void treeWalk() {
treeWalk(getRootElement());
}
public
void treeWalk(Element element) {
for (
int i = 0, size = element.nodeCount(); i < size; i++) {
Node node = element.node(i);
if (node
instanceof Element) {
treeWalk((Element) node);
}
else { // do something....
}
}
}
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public
class MyVisitor
extends VisitorSupport {
public
void visit(Element element){
System.out.println(element.getName());
}
public
void visit(Attribute attr){
System.out.println(attr.getName());
}
}
调用: root.accept(new MyVisitor())
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public
void bar(Document document) {
List list = document.selectNodes( //foo/bar );
Node node = document.selectSingleNode(//foo/bar/author);
String name = node.valueOf( @name );
}
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public
void findLinks(Document document)
throws DocumentException {
List list = document.selectNodes( //a/@href );
for (Iterator iter = list.iterator(); iter.hasNext(); ) {
Attribute attribute = (Attribute) iter.next();
String url = attribute.getValue();
}
}
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// XML转字符串
Document document = ...;
String text = document.asXML();
// 字符串转XML
String text =
Document document = DocumentHelper.parseText(text);
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public Document styleDocument(
Document document,
String stylesheet
)
throws Exception {
// load the transformer using JAXP
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(
new StreamSource( stylesheet )
);
// now lets style the given document
DocumentSource source =
new DocumentSource( document );
DocumentResult result =
new DocumentResult();
transformer.transform( source, result );
// return the transformed document
Document transformedDoc = result.getDocument();
return transformedDoc;
}
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public Document createDocument() {
Document document = DocumentHelper.createDocument();
Element root = document.addElement(root);
Element author1 =
root
.addElement(author)
.addAttribute(name, James)
.addAttribute(location, UK)
.addText(James Strachan);
Element author2 =
root
.addElement(author)
.addAttribute(name, Bob)
.addAttribute(location, US)
.addText(Bob McWhirter);
return document;
}
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FileWriter out =
new FileWriter( foo.xml );
document.write(out);
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public
void write(Document document)
throws IOException {
// 指定文件
XMLWriter writer =
new XMLWriter(
new FileWriter( output.xml )
);
writer.write( document );
writer.close();
// 美化格式
OutputFormat format = OutputFormat.createPrettyPrint();
writer =
new XMLWriter( System.out, format );
writer.write( document );
// 缩减格式
format = OutputFormat.createCompactFormat();
writer =
new XMLWriter( System.out, format );
writer.write( document );
}
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holen.xml
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/**
* 建立一个XML文档,文档名由输入属性决定
*
@param filename 需建立的文件名
*
@return 返回操作结果, 0表失败, 1表成功
*/
public
int createXMLFile(String filename){
/** 返回操作结果, 0表失败, 1表成功 */
int returnValue = 0;
/** 建立document对象 */
Document document = DocumentHelper.createDocument();
/** 建立XML文档的根books */
Element booksElement = document.addElement("books");
/** 加入一行注释 */
booksElement.addComment("This is a test for dom4j, holen, 2004.9.11");
/** 加入第一个book节点 */
Element bookElement = booksElement.addElement("book");
/** 加入show属性内容 */
bookElement.addAttribute("show","yes");
/** 加入title节点 */
Element titleElement = bookElement.addElement("title");
/** 为title设置内容 */
titleElement.setText("Dom4j Tutorials");
/** 类似的完成后两个book */
bookElement = booksElement.addElement("book");
bookElement.addAttribute("show","yes");
titleElement = bookElement.addElement("title");
titleElement.setText("Lucene Studing");
bookElement = booksElement.addElement("book");
bookElement.addAttribute("show","no");
titleElement = bookElement.addElement("title");
titleElement.setText("Lucene in Action");
/** 加入owner节点 */
Element ownerElement = booksElement.addElement("owner");
ownerElement.setText("O'Reilly");
try{
/** 将document中的内容写入文件中 */
XMLWriter writer =
new XMLWriter(
new FileWriter(
new File(filename)));
writer.write(document);
writer.close();
/** 执行成功,需返回1 */
returnValue = 1;
}
catch(Exception ex){
ex.printStackTrace();
}
return returnValue;
}
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/**
* 修改XML文件中内容,并另存为一个新文件
* 重点掌握dom4j中如何添加节点,修改节点,删除节点
*
@param filename 修改对象文件
*
@param newfilename 修改后另存为该文件
*
@return 返回操作结果, 0表失败, 1表成功
*/
public
int ModiXMLFile(String filename,String newfilename){
int returnValue = 0;
try{
SAXReader saxReader =
new SAXReader();
Document document = saxReader.read(
new File(filename));
/** 修改内容之一: 如果book节点中show属性的内容为yes,则修改成no */
/** 先用xpath查找对象 */
List list = document.selectNodes("/books/book/@show" );
Iterator iter = list.iterator();
while(iter.hasNext()){
Attribute attribute = (Attribute)iter.next();
if(attribute.getValue().equals("yes")){
attribute.setValue("no");
}
}
/**
* 修改内容之二: 把owner项内容改为Tshinghua
* 并在owner节点中加入date节点,date节点的内容为2004-09-11,还为date节点添加一个属性type
*/
list = document.selectNodes("/books/owner" );
iter = list.iterator();
if(iter.hasNext()){
Element ownerElement = (Element)iter.next();
ownerElement.setText("Tshinghua");
Element dateElement = ownerElement.addElement("date");
dateElement.setText("2004-09-11");
dateElement.addAttribute("type","Gregorian calendar");
}
/** 修改内容之三: 若title内容为Dom4j Tutorials,则删除该节点 */
list = document.selectNodes("/books/book");
iter = list.iterator();
while(iter.hasNext()){
Element bookElement = (Element)iter.next();
Iterator iterator = bookElement.elementIterator("title");
while(iterator.hasNext()){
Element titleElement=(Element)iterator.next();
if(titleElement.getText().equals("Dom4j Tutorials")){
bookElement.remove(titleElement);
}
}
}
try{
/** 将document中的内容写入文件中 */
XMLWriter writer =
new XMLWriter(
new FileWriter(
new File(newfilename)));
writer.write(document);
writer.close();
/** 执行成功,需返回1 */
returnValue = 1;
}
catch(Exception ex){
ex.printStackTrace();
}
}
catch(Exception ex){
ex.printStackTrace();
}
return returnValue;
}
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/**
* 格式化XML文档,并解决中文问题
*
@param filename
*
@return
*/
public
int formatXMLFile(String filename){
int returnValue = 0;
try{
SAXReader saxReader =
new SAXReader();
Document document = saxReader.read(
new File(filename));
XMLWriter writer =
null;
/** 格式化输出,类型IE浏览一样 */
OutputFormat format = OutputFormat.createPrettyPrint();
/** 指定XML编码 */
format.setEncoding("GBK");
writer=
new XMLWriter(
new FileWriter(
new File(filename)),format);
writer.write(document);
writer.close();
/** 执行成功,需返回1 */
returnValue = 1;
}
catch(Exception ex){
ex.printStackTrace();
}
return returnValue;
}
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Dom4jDemo.java
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package com.holen.dom4j;
import java.io.File;
import java.io.FileWriter;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
/**
*
@author Holen Chen
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