content: package org.example.Servlet;
  
  import javax.servlet.*;
  import javax.servlet.annotation.WebFilter;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpSession;
  import java.io.IOException;
  
  @WebFilter("/catalog/*")
  public class AuthFilter implements Filter {
  
      @Override
      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
              throws IOException, ServletException {
  
          HttpServletRequest httpRequest = (HttpServletRequest) request;
          HttpServletResponse httpResponse = (HttpServletResponse) response;
          HttpSession session = httpRequest.getSession(false);
  
          if (session != null && session.getAttribute("user") != null) {
              chain.doFilter(request, response);
          } else {
              httpResponse.sendRedirect(httpRequest.getContextPath() + "/login");
          }
      }
  
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
      }
  
      @Override
      public void destroy() {
      }
  }
  