filter进不去是哪里出问题了

public class LoginFilter implements Filter{

@Override
public void destroy() {
    // TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
    System.out.println("lanjieqi");
    //获取HttpSession对象，判断是否登陆
    HttpServletRequest req =  (HttpServletRequest) request;
    HttpServletResponse res = (HttpServletResponse) response;
    HttpSession session = req.getSession();
    if(session.getAttribute("user")==null){
        res.sendRedirect(req.getContextPath() + "/linli1/index.jsp");
    }else{
        chain.doFilter(request, response);
    }

}

@Override
public void init(FilterConfig arg0) throws ServletException {

}

https://blog.csdn.net/qq_34719291/article/details/73181403