xml解析-dom4j范例

dom4j是一个第三方xml解析库，所以要在工程中加引用库。
下载了dom4j项目之后，解压缩，将其目录下面jar包加入class path下面。
　（Properties->Java Build Path -> Add External JARs…）加入工程就可以使用了。

这里分两个例程，一个创建xml文档，一个读取xml文档并解析

创建xml文档并添加节点数据

package dom4j;import java.io.FileOutputStream;import java.io.IOException;import org.dom4j.Document;import org.dom4j.DocumentHelper;import org.dom4j.Element;import org.dom4j.io.OutputFormat;import org.dom4j.io.XMLWriter;public class Dom4jDemo {    public Dom4jDemo() {        // TODO Auto-generated constructor stub    }    /**     * 创建xml文档，并添加元素。     *      * @param args     * @throws IOException     */    public static void main(String[] args) throws IOException {        // 第一种方式：创建文档节点        Document document = DocumentHelper.createDocument();        // 创建根节点,并添加到文档节点中        Element element = DocumentHelper.createElement("student");        document.setRootElement(element);        XMLWriter writer = new XMLWriter();        writer.write(document);//可以直接把document节点下所有数据打印出来        // 第二种方式,先创建文档根节点，然后创建文档节点。并将根节点引用作为参数        Element element2 = DocumentHelper.createElement("students");// 头节点students        Document document1 = DocumentHelper.createDocument(element2);        Element student1 = element2.addElement("student");// 头节点创建子节点        student1.addAttribute("name", "vincent");// 子节点属性        Element birthday = student1.addElement("birthday");// 子节点的子节点        birthday.setText("1993-01-21");        Element school = student1.addElement("school");        school.setText("GDUT");        writer.write(document1);// 输出到终端        // 输出到文件，格式化输出，第一个参数表示子节点和父节点要缩进多少个空格        //第二个参数表示节点间是否要另起一行。每个新的节点都是独自一行        OutputFormat format = new OutputFormat("    ", true);        writer = new XMLWriter(new FileOutputStream("src/student.xml"), format);        Element student2 = element2.addElement("student");        student2.addAttribute("name", "ok");        Element student2_birthday = student2.addElement("birthday");        student2_birthday.setText("1232-3-12");        Element student2_school = student2.addElement("school");        student2_school.setText("GDUT");        writer.write(document1);        writer.flush();        writer.close();    }}

输出的结果是

<?xml version="1.0" encoding="UTF-8"?><students>    <student name="vincent">        <birthday>1993-01-21</birthday>        <school>GDUT</school>    </student>    <student name="ok">        <birthday>1232-3-12</birthday>        <school>GDUT</school>    </student></students>

解析生成的这个xml文档

package dom4j;import java.io.File;import java.util.Iterator;import java.util.List;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.Element;import org.dom4j.io.SAXReader;public class ParseDom4j {    public ParseDom4j() {        // TODO Auto-generated constructor stub    }    public static void main(String[] args) throws DocumentException {        //saxreader是通过sax事件获取（构造）dom4j树        SAXReader saxReader = new SAXReader();        Document document = saxReader.read(new File("src/student.xml"));        System.out.println("Docment Node Name " + document.getName());        Element root = document.getRootElement();        System.out.println("Root Name" + root.getName());        List<Element> elements = root.elements();// 获取根元素下的所有子节点        System.out.println("根元素下的所有子节点数" + elements.size());        List<Element> students = root.elements("student");// 获取根元素下的所有student子节点        System.out.println("根元素下的所有student节点数" + students.size());        for (Iterator iterator = students.iterator(); iterator.hasNext();) {            Element element = (Element) iterator.next();            System.out.println(element.attributeValue("name"));            List<Element> childNode = element.elements();            for (Iterator iterator2 = childNode.iterator(); iterator2.hasNext();) {                Element childElement = (Element) iterator2.next();                System.out.println(childElement.getName() + "\t\t" + childElement.getText());            }        }    }}

输出

Docment Node Name file:///home/cindy/eclipseworkspace/XMLParseSax/src/student.xml
Root Names tudents
根元素下的所有子节点数2
根元素下的所有student节点数2
vincent
birthday 1993-01-21
school GDUT
ok
birthday 1232-3-12
school GDUT