這個空指針異常我是一臉懵逼的

package cn.itcast.DTD;

import java.io.File;

import java.util.List;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

import org.junit.Test;

public class DTD_dom4j_Dema1 {

@Test

public void test() {

try {

SAXReader sr = new SAXReader();

Document docu = sr.read("src/web_dtd.xml");

Element rootElement = docu.getRootElement();

//System.out.println(rootElement.attributeValue("version"));//1.0

List<Element> list = rootElement.elements();

// for(Element e : list) {

// System.out.println(e.getName());//servletservlet-mapping welcome-file-list

// }

//Element childElement = rootElement.element("servlet-mapping");

//System.out.println(childElement.getName());//servlet-mapping

//System.out.println(childElement.elementText("url-pattern"));//http://www.baidu.com

Element childElement = rootElement.element("servlet-name");

Element kid = childElement.element("servlet-name");

String a = kid.getText();

System.out.println(a);

藍色部分是報錯的原因，我就想用寫getText();方法擷取文本，最後報了空指針，懵逼了大叔

} catch (DocumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}