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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | 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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | 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
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | 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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