我的拦截器问题在哪里，为什么我连login.jsp都打不开了

package com.imooc.web.filter;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class AuthFilter implements Filter {
	public void init(FilterConfig fConfig) throws ServletException {
		// TODO Auto-generated method stub
	}
	
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		 HttpServletRequest req= (HttpServletRequest)request;
		 HttpServletResponse res=(HttpServletResponse)response;
		 String user=(String)req.getSession().getAttribute("existList");
        if(user!=null) {
        	chain.doFilter(request, response);
        	return;
        }else {
        	request.setAttribute("msg", "密码或用户名错误");
        	res.sendRedirect(req.getContextPath()+"/login.jsp");
        	return;
        }
		
		
	}
	
	public void destroy() {
		// TODO Auto-generated method stub
	}

	

	

}

<filter>
    <filter-name>AuthFilter</filter-name>
    <filter-class>com.imooc.web.filter.AuthFilter</filter-class>
 </filter>
  <filter-mapping>
     <filter-name>AuthFilter</filter-name>
     <url-pattern>/*</url-pattern>
  </filter-mapping>