过滤器配置

1、新增一个LoginFilter集成Filter，重写doFilter方法。类上可以给一个注解@WebFilter(filterName = “loginFilter”)

private String login = "/log_in.html";    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {        HttpServletRequest request = (HttpServletRequest)req;        HttpServletResponse response = (HttpServletResponse)resp;        String path = request.getRequestURI();        if(path.endsWith(login)){            chain.doFilter(req,resp);            return;        }        HttpSession session = request.getSession();        User user = (User) session.getAttribute("loginUser");        if(user==null){            response.sendRedirect(request.getContextPath()+login);            return;        }        chain.doFilter(req,resp);    }

2、配置web.xml。路径中配置.html的话就只过滤html网页，不过滤静态资源这些

<filter-mapping>    <filter-name>loginFilter</filter-name>    <url-pattern>*.html</url-pattern>  </filter-mapping>