Net Book mall 11 -- background login filter, 11 -- Filter
1. web. xml
<filter><filter-name>AdminLoginFilter</filter-name><filter-class>cn.itcast.goods.admin.web.filter.AdminLoginFilter</filter-class></filter><filter-mapping><filter-name>AdminLoginFilter</filter-name><url-pattern>/adminjsps/admin/*</url-pattern><url-pattern>/admin/*</url-pattern></filter-mapping>
2. AdminLoginFilter
Public void doFilter (ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {HttpServletRequest req = (HttpServletRequest) request; Object admin = req. getSession (). getAttribute ("admin"); if (admin = null) {request. setAttribute ("msg", "You have not logged on. Don't try it out! "); Request. getRequestDispatcher ("/adminjsps/login. jsp "). forward (request, response);} else {chain. doFilter (request, response );}}