package cn.itcast;import java.io.IOException;import javax.servlet.GenericServlet;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class ServletDemo1 extends GenericServlet {    @Override    public void service(ServletRequest req, ServletResponse res)            throws ServletException, IOException {                res.getOutputStream().write("hello servlet".getBytes());    }}

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.4"     xmlns="http://java.sun.com/xml/ns/j2ee"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee     http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">    <servlet>    <servlet-name>ServletDemo1</servlet-name>    <servlet-class>cn.itcast.ServletDemo1</servlet-class></servlet><servlet-mapping>    <servlet-name>ServletDemo1</servlet-name>    <url-pattern>/ServletDemo1</url-pattern></servlet-mapping>      <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>