转：在java中使用dom4j解析xml

 

JAVA 使用Dom4j 解析XML

 

 

Java DOM4J Parser - Parse XML Document

Dom4j下载及使用Dom4j读写XML简介

在java中使用dom4j解析xml

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：

 

分类:  Java

标签:  XML