dom4j解析xml

 新建java 工程，然后新建lib文件夹，将dom4j的jar包和dtd约束拷贝进来，

然后在src下添加web.xml,添加过程中选择约束

 

新建java 类

package demo1124;



import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class Test {

	public static void main(String[] args) throws DocumentException {
		SAXReader reader = new SAXReader();
		Document doc = reader.read("src/web.xml");
		Element rootElement = doc.getRootElement();
		System.out.println(rootElement.getName());
		System.out.println(rootElement.attributeValue("version"));
		List<Element> childElements = rootElement.elements();
		for (Element element : childElements) {
			if ("servlet".equals(element.getName())) {
				Element servletName = element.element("servlet-name");
				Element servletClass = element.element("servlet-class");
				System.out.println(servletName.getText());
				System.out.println(servletClass.getText());
				
			}
			if ("servlet-mapping".equals(element.getName())) {
				Element servletName = element.element("servlet-name");
				Element urlPattern = element.element("url-pattern");
				System.out.println(servletName.getText());
				System.out.println(urlPattern.getText());
				
			}
		}
		
	}

}

web.xml 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app SYSTEM "../lib/web-app_2_3.dtd" >
<web-app version="2.3">
	<servlet>
		<servlet-name>hello</servlet-name>
		<servlet-class>HelloServlet</servlet-class>
	</servlet>

	<servlet-mapping>
		<servlet-name>hello</servlet-name>
		<url-pattern>/hello</url-pattern>
	</servlet-mapping>
</web-app>