servlet三种实现方式之三通过继承HttpServlet开发servlet

servlet有三种实现方式：

1.实现servlet接口

2.继承GenericServlet

3.通过继承HttpServlet开发servlet

第三种：

 1 import java.io.*;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.http.*;
 5 
 6 
 7 public class hellohttp extends HttpServlet {
 8 
 9     //处理get请求
10     //req用于获取客户端（浏览器）的信息
11     //res用于向客户端（浏览器）返回信息
12     public void doGet(HttpServletRequest req, HttpServletResponse res)
13             throws ServletException, IOException {
14         
15         //业务逻辑
16         try{
17             PrintWriter pw=res.getWriter();
18             pw.println("hello,http");
19         }catch(Exception e){
20             e.printStackTrace();
21         }
22     }
23     //处理post请求
24     //req用于获取客户端（浏览器）的信息
25     //res用于向客户端（浏览器）返回信息
26     public void doPost(HttpServletRequest req,HttpServletResponse res)
27             throws ServletException,IOException
28     {
29         //合二为一，业务逻辑处理方式都一样
30         this.doGet(req, res);
31     }
32 
33     public void init() throws ServletException{
34         // Put your code here
35     }
36 
37     public void destroy() {
38         super.destroy(); // Just puts "destroy" string in log
39         // Put your code here
40     }
41 }