package com.jsn.web.servlet;

 1 package com.jsn.web.servlet;
 2 
 3 import java.io.IOException;
 4 
 5 import javax.servlet.Servlet;
 6 import javax.servlet.ServletConfig;
 7 import javax.servlet.ServletException;
 8 import javax.servlet.ServletRequest;
 9 import javax.servlet.ServletResponse;
10 
11 public class HelloServlet implements Servlet {
12 
13     @Override
14     public void destroy() {
15         // TODO Auto-generated method stub
16         System.out.println("hello");
17     }
18 
19     @Override
20     public ServletConfig getServletConfig() {
21         // TODO Auto-generated method stub
22         return null;
23     }
24 
25     @Override
26     public String getServletInfo() {
27         // TODO Auto-generated method stub
28         return null;
29     }
30 
31     @Override
32     public void init(ServletConfig arg0) throws ServletException {
33         // TODO Auto-generated method stub
34         System.out.println("hello init");
35     }
36 
37     @Override
38     public void service(ServletRequest arg0, ServletResponse response) throws ServletException, IOException {
39         // TODO Auto-generated method stub
40         response.getWriter().write("hello service response");
41     }
42 
43 }

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 "http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
 3   dyweb
 4   
 5   
 6   HelloServlet
 7   class>com.jsn.web.servlet.HelloServletclass>
 8   
 9   
10   
11   
12   
13   HelloServlet
14   /hellworld
15   
16   
17   
18     index.html
19     index.htm
20     index.jsp
21     default.html
22     default.htm
23     default.jsp
24   
25 

servlet 三种方式   

1、implements Servlet

2、GenericServlet

3、HttpServlet    doget 

Servlet【接口】
GenericServlet【是 Servlet实现类】
httpservlet 是genericservlet的子类】

helloservlet 是 httpservlet 子类