java中用Dom4j解析xml

http://www.cnblogs.com/nerxious/archive/2013/05/04/3060263.html

虽然Java中已经有了Dom和Sax这两种标准解析方式

但其操作起来并不轻松，对于我这么一个初学者来说，其中部分代码是活生生的恶心

为此，伟大的第三方开发组开发出了Jdom和Dom4j等工具

鉴于目前的趋势，我们这里来讲讲Dom4j的基本用法，不涉及递归等复杂操作

 

Dom4j的用法很多，官网上的示例有那么点儿晦涩，这里就不写了

首先我们需要出创建一个xml文档，然后才能对其解析

xml文档：

<?xml version="1.0" encoding="UTF-8"?> <books>    <book id="001">       <title>Harry Potter</title>       <author>J K. Rowling</author>    </book>    <book id="002">       <title>Learning XML</title>       <author>Erik T. Ray</author>    </book> </books> 

 

示例一：用List列表的方式来解析xml

import java.io.File;import java.util.List;import org.dom4j.Attribute;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.io.SAXReader;public class Demo {public static void main(String[] args) throws Exception {SAXReader reader = new SAXReader();File file = new File("books.xml");Document document = reader.read(file);Element root = document.getRootElement();List<Element> childElements = root.elements();for (Element child : childElements) {//未知属性名情况下/*List<Attribute> attributeList = child.attributes();for (Attribute attr : attributeList) {System.out.println(attr.getName() + ": " + attr.getValue());}*///已知属性名情况下System.out.println("id: " + child.attributeValue("id"));//未知子元素名情况下/*List<Element> elementList = child.elements();for (Element ele : elementList) {System.out.println(ele.getName() + ": " + ele.getText());}System.out.println();*///已知子元素名的情况下System.out.println("title" + child.elementText("title"));System.out.println("author" + child.elementText("author"));//这行是为了格式化美观而存在System.out.println();}}}

 

示例二：使用Iterator迭代器的方式来解析xml

import java.io.File;import java.util.Iterator;import org.dom4j.Attribute;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.io.SAXReader;public class Demo {public static void main(String[] args) throws Exception {SAXReader reader = new SAXReader();Document document = reader.read(new File("books.xml"));Element root = document.getRootElement();Iterator it = root.elementIterator();while (it.hasNext()) {Element element = (Element) it.next();//未知属性名称情况下/*Iterator attrIt = element.attributeIterator();while (attrIt.hasNext()) {Attribute a  = (Attribute) attrIt.next();System.out.println(a.getValue());}*///已知属性名称情况下System.out.println("id: " + element.attributeValue("id"));//未知元素名情况下/*Iterator eleIt = element.elementIterator();while (eleIt.hasNext()) {Element e = (Element) eleIt.next();System.out.println(e.getName() + ": " + e.getText());}System.out.println();*///已知元素名情况下System.out.println("title: " + element.elementText("title"));System.out.println("author: " + element.elementText("author"));System.out.println();}}}

 运行结果：

示例三：创建xml文档并输出到文件

import java.io.File;import java.io.FileOutputStream;import org.dom4j.Document;import org.dom4j.DocumentHelper;import org.dom4j.Element;import org.dom4j.io.OutputFormat;import org.dom4j.io.XMLWriter;public class Demo {public static void main(String[] args) throws Exception {Document doc = DocumentHelper.createDocument();//增加根节点Element books = doc.addElement("books");//增加子元素Element book1 = books.addElement("book");Element title1 = book1.addElement("title");Element author1 = book1.addElement("author");Element book2 = books.addElement("book");Element title2 = book2.addElement("title");Element author2 = book2.addElement("author");//为子节点添加属性book1.addAttribute("id", "001");//为元素添加内容title1.setText("Harry Potter");author1.setText("J K. Rowling");book2.addAttribute("id", "002");title2.setText("Learning XML");author2.setText("Erik T. Ray");//实例化输出格式对象OutputFormat format = OutputFormat.createPrettyPrint();//设置输出编码format.setEncoding("UTF-8");//创建需要写入的File对象File file = new File("D:" + File.separator + "books.xml");//生成XMLWriter对象，构造函数中的参数为需要输出的文件流和格式XMLWriter writer = new XMLWriter(new FileOutputStream(file), format);//开始写入，write方法中包含上面创建的Document对象writer.write(doc);}}

 运行结果：