package jd.com.test;

 import javax.servlet.ServletException;

 import javax.servlet.annotation.WebServlet;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import java.io.IOException;

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

 public class ServletDemo extends HttpServlet {

     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

         doGet(request,response);

     }

     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

             System.out.println("访问demo1了。");

     }

 }

 package jd.com.test;

 import javax.servlet.*;

 import javax.servlet.annotation.WebFilter;

 import java.io.IOException;

 @WebFilter(urlPatterns = "/demo1")

 public class MyFilter implements Filter {

     @Override

     public void init(FilterConfig filterConfig) throws ServletException {

     }

     @Override

     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

         System.out.println("来到Myfilter");

         filterChain.doFilter(servletRequest,servletResponse);

     }

     @Override

     public void destroy() {

     }

 }