在java中使用dom4j解析xml(示例代码)

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：

在java中使用dom4j解析xml(示例代码)

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