简单配置过滤器

@Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException { // 过滤用户请求，判断是否登录 HttpServletRequest httpServletRequest = (HttpServletRequest)request; HttpServletResponse httpServletResponse = (HttpServletResponse)response; httpServletRequest.setCharacterEncoding("utf-8"); httpServletResponse.setCharacterEncoding("utf-8"); String username = (String)httpServletRequest.getSession().getAttribute("username"); if (username == null) { String path = httpServletRequest.getContextPath(); httpServletResponse.sendRedirect(path+"/index.jsp"); } filterChain.doFilter(httpServletRequest, httpServletResponse); }

<!-- 配置 过滤器 --> <filter> <filter-name>MyFilter</filter-name> <filter-class>com.filter.MyFilter</filter-class> </filter> <filter-mapping> <filter-name>MyFilter</filter-name> <!-- /*表示过滤所有页面 ，/main.jsp 表示只过滤main.jsp页面--> <url-pattern> /main.jsp</url-pattern> </filter-mapping> <filter-mapping> <filter-name>MyFilter</filter-name> <!-- /*表示过滤所有页面 /addProduct.jsp 表示只过滤addProduct.jsp页面--> <url-pattern>/addProduct.jsp</url-pattern> </filter-mapping>