servlet3.0

1、之前我们创建的项目是servlet2.5，之前的版本，servlet、filter、listener需要配置web.xml

在servlet3.0的时候，没有web.xml，提供注解开发。

servlet注解：@WebServlet(name = "ServletDemo",urlPatterns ={"/demo1","/demo21"})

filter注解：@WebFilter(urlPatterns = "/demo1")

listener注解：@WebListener()

例子：

 1 package jd.com.test;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.annotation.WebServlet;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServletRequest;
 7 import javax.servlet.http.HttpServletResponse;
 8 import java.io.IOException;
 9 
10 @WebServlet(name = "ServletDemo",urlPatterns ={"/demo1","/demo21"} )
11 public class ServletDemo extends HttpServlet {
12     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
13         doGet(request,response);
14     }
15 
16     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
17             System.out.println("访问demo1了。");
18     }
19 }

 1 package jd.com.test;
 2 
 3 import javax.servlet.*;
 4 import javax.servlet.annotation.WebFilter;
 5 import java.io.IOException;
 6 
 7 
 8 @WebFilter(urlPatterns = "/demo1")
 9 public class MyFilter implements Filter {
10 
11     @Override
12     public void init(FilterConfig filterConfig) throws ServletException {
13 
14     }
15 
16     @Override
17     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
18         System.out.println("来到Myfilter");
19         filterChain.doFilter(servletRequest,servletResponse);
20     }
21 
22     @Override
23     public void destroy() {
24 
25     }
26 }