在java中使用dom4j解析xml(示例代码)

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：

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