校验用户是否登录过滤器Filter

1、首先需要在web.xml中配置过滤器

<!-- servlet 校验是否登录过滤器 --> <filter> <filter-name>CheckLoginFilter</filter-name> <filter-class>net.cnki.tpi.cms.util.CheckLoginFilter</filter-class> <init-param> <param-name>redirectURL</param-name> <param-value>/login.jsp</param-value> </init-param> <init-param> <param-name>notCheckURLList </param-name> <param-value>/error.jsp;/login.jsp</param-value> </init-param> </filter> <filter-mapping> <filter-name>CheckLoginFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>


2、然后新创建一个CheckLoginFilter.java类，代码如下：

/** * 校验用户是否已登录过滤器 * @author lpz * */ public class CheckLoginFilter implements Filter { private FilterConfig filterConfig = null; private String redirectURL = null; private List notCheckURLList = new ArrayList(); public CheckLoginFilter() { } public void destroy() { notCheckURLList.clear(); } public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest)servletRequest; HttpServletResponse response = (HttpServletResponse)servletResponse; HttpSession session = request.getSession(); Object userInfo = session.getAttribute("userInfo"); if(!checkRequestURIIntNotFilterList(request) && userInfo==null){ //重定向到指定页面 response.sendRedirect(request.getContextPath() + redirectURL); }else{ //继续响应请求 chain.doFilter(servletRequest, servletResponse); } } public void init(FilterConfig fConfig) throws ServletException { this.filterConfig = fConfig; redirectURL = filterConfig.getInitParameter("redirectURL"); String notCheckURLListStr = filterConfig.getInitParameter("notCheckURLList"); if(!MyStringUtil.isNullOrEmpty(notCheckURLListStr)){ //将字符串转化为list notCheckURLList = MyStringUtil.convStrToList(notCheckURLListStr,";"); } } /** * 校验当前请求是否在不过滤的列表中 * @param request * @return */ private boolean checkRequestURIIntNotFilterList(HttpServletRequest request) { String uri = request.getServletPath() + (request.getPathInfo() == null ? "" : request.getPathInfo()); return notCheckURLList.contains(uri); } }