本文主要是介绍dom4j解析和生成XML文件，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
转化XML
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;public class Foo {public Document parse(URL url) throws DocumentException {SAXReader reader = new SAXReader();Document document = reader.read(url);return document;}
}使用迭代器
document可以通过几个返回Java标准迭代器的方法实现遍历：
public void bar(Document document) throws DocumentException {Element root = document.getRootElement();// iterate through child elements of rootfor ( Iterator i = root.elementIterator(); i.hasNext(); ) {Element element = (Element) i.next();// do something}// iterate through child elements of root with element name "foo"for ( Iterator i = root.elementIterator( "foo" ); i.hasNext(); ) {Element foo = (Element) i.next();// do something}// iterate through attributes of root for ( Iterator i = root.attributeIterator(); i.hasNext(); ) {Attribute attribute = (Attribute) i.next();// do something}}快速循环
快速遍历大文件：
public void treeWalk(Document document) {treeWalk( document.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....}}}创建XML文档
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;public class Foo {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;}
}将文档写入文件
一种快速而且简单的方式如下：
FileWriter out = new FileWriter( "foo.xml" );
document.write( out );如果想要修改输出的格式，如智能缩进输出或者紧凑输出，或者你想要使用writer对象或者OutputStream对象来完成其他任务，则可以使用XMLWriter类。
import org.dom4j.Document;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;public class Foo {public void write(Document document) throws IOException {// lets write to a fileXMLWriter writer = new XMLWriter(new FileWriter( "output.xml" ));writer.write( document );writer.close();// Pretty print the document to System.outOutputFormat format = OutputFormat.createPrettyPrint();writer = new XMLWriter( System.out, format );writer.write( document );// Compact format to System.outformat = OutputFormat.createCompactFormat();writer = new XMLWriter( System.out, format );writer.write( document );}
}与String的转化
如果有到Document或者其他结点如Attribute、Element等的引用，则可以用asXML()方法将其转化为默认的XML文本。
Document document = ...;
String text = document.asXML();如果有String形式的XML，则可以使用DocumentHelper.parseText()将其转化为Document。
String text = "<person> <name>James</name> </person>";
Document document = DocumentHelper.parseText(text);其他操作
1 取得某结点下的某个子节点或属性
Element root = document.getRootElement();
Element elem = root.element("book");
Attribute attribute = root.attribute("id");2 取得属性的内容
String text = attribute.getText();3 删除某属性
Attribute attribute=root.attribute("id");
root.remove(attribute);一个完整的解析和生成XML文件示例
package test;import java.io.*;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.dom4j.Attribute;class XMLHelper {/*** 解析XML* @param filename 要解析的XML的文件名*/public static void resolveXML(String filename) {try {SAXReader reader = new SAXReader();Document document = reader.read(new File(filename));Element root = document.getRootElement();System.out.println("Root: " + root.getName());for (Iterator it = root.elementIterator(); it.hasNext(); ) {Element e = (Element)it.next();System.out.print(e.getName());//遍历属性for (Iterator it1 = e.attributeIterator(); it1.hasNext(); ) {Attribute attribute = (Attribute)it1.next();System.out.println("[" + attribute.getName() + ": " +attribute.getText() + "]");}//遍历子节点for (Iterator it2 = e.elementIterator(); it2.hasNext(); ) {Element ee = (Element)it2.next();System.out.println(" " + ee.getName() + ": " + ee.getText() + " ");}}} catch (Exception ex) {ex.printStackTrace();}}public static Document createDocument() {Document document = DocumentHelper.createDocument();Element root = document.addElement("bookstore");//add bookElement book = root.addElement("book").addAttribute("category", "COOKING");book.addElement("title").addText("Everyday Italian");book.addElement("author").addText("Giada De Laurentiis");book.addElement("year").addText("2005");book.addElement("price").addText("30.00");//add bookbook = root.addElement("book").addAttribute("category", "CHILDREN");book.addElement("title").addText("Harry Potter");book.addElement("author").addText("J K. Rowling");book.addElement("year").addText("2005");book.addElement("price").addText("29.99");return document;}/*** 生成XML文件* @param filename 将生成的XML输出到该文件*/public static void write(String filename) {Document document = createDocument(); try {//write to a fileOutputFormat f=OutputFormat.createPrettyPrint();XMLWriter writer = new XMLWriter(new FileWriter(filename), f);writer.write(document);writer.close();//Pretty print the document to System.out/*OutputFormat format = OutputFormat.createPrettyPrint();writer = new XMLWriter(System.out, format);writer.write(document);*///Compact print the document to System.out/*format = OutputFormat.createCompactFormat();writer = new XMLWriter(System.out, format);writer.write(document);*/} catch (Exception ex) {ex.printStackTrace();}}
}public class Main {public static void main(String[] args) throws Exception{String filename = "E:\\Eclipse Project\\WebTest\\WebContent\\myxml.xml";XMLHelper.resolveXML(filename);filename = "E:\\Eclipse Project\\WebTest\\WebContent\\myxml2.xml";XMLHelper.write(filename);}
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