Login的登录过滤器

@WebFilter("/*")
public class LoginFilter implements Filter {

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {

        //强制转换
        HttpServletRequest request = (HttpServletRequest) req;
        //获取资源请求路径
        String uri = request.getRequestURI();
        //判断是否包含登陆的相关资源
        if(uri.contains("/login.jsp")||uri.contains("/loginServlet")||uri.contains("/css/")||uri.contains("/js/")||uri.contains("/checkCodeServlet")){
            //包含，用户就是想登录，放行
            chain.doFilter(req, resp);
        }else{
            //不包含，需要验证用户是否登陆登录
            //3.从session中获取user
            Object user = request.getSession().getAttribute("user");
            if (user!=null){
                //登陆了，放行
                chain.doFilter(req, resp);
            }else{
                //没有登陆，跳转页面
                request.setAttribute("login_msg","您尚未登录，请登录");
                request.getRequestDispatcher("/login.jsp").forward(request,resp);
            }
        }

    }

    public void init(FilterConfig config) throws ServletException {

    }

    public void destroy() {

    }

}