刚刚接触Filter求注释能加深理解
?public class CheckLoginFilter
? implements Filter
?{
? protected FilterConfig filterConfig = null;
? private String redirectURL = null;
? private List notCheckURLList = new ArrayList();
? private String sessionKey = null;
?
? public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException
? {
? HttpServletRequest request = (HttpServletRequest) servletRequest;
? HttpServletResponse response = (HttpServletResponse) servletResponse;
?
? HttpSession session = request.getSession();
? if(sessionKey == null)
? {
? filterChain.doFilter(request, response);
? return;
? }
? if((!checkRequestURIIntNotFilterList(request)) && session.getAttribute(sessionKey) == null)
? {
? response.sendRedirect(request.getContextPath() + redirectURL);
? return;
? }
? filterChain.doFilter(servletRequest, servletResponse);
? }
?
? public void destroy()
? {
? notCheckURLList.clear();
? }
?
? private boolean checkRequestURIIntNotFilterList(HttpServletRequest request)
? {
? String uri = request.getServletPath() + (request.getPathInfo() == null ? "" : request.getPathInfo());
? return notCheckURLList.contains(uri);
? }
?
? public void init(FilterConfig filterConfig) throws ServletException
? {
? this.filterConfig = filterConfig;
? redirectURL = filterConfig.getInitParameter("redirectURL");
? sessionKey = filterConfig.getInitParameter("checkSessionKey");
?
? String notCheckURLListStr = filterConfig.getInitParameter("notCheckURLList");
?
? if(notCheckURLListStr != null)
? {
? StringTokenizer st = new StringTokenizer(notCheckURLListStr, ";");
? notCheckURLList.clear();
? while(st.hasMoreTokens())
? {
? notCheckURLList.add(st.nextToken());
? }
? }
? }
?}
求专家帮我把这个过滤器方法中一些主要代码加下注释,IF判断条件也帮忙注释一下,在下不胜感激!
[解决办法]
//这是一个检查请求安全权限的Filter，可以配置。起作用时会将不符合条件的请求重定向。
?public class CheckLoginFilter
? implements Filter //过滤器都要实现该接口
?{
? protected FilterConfig filterConfig = null; //用于保存配置信息
? private String redirectURL = null;
? private List notCheckURLList = new ArrayList(); //可以免于处理的URL清单
? private String sessionKey = null; //若null则过滤器不起作用，希望启动本过滤器的时候要设一个非null值
?
? public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException
? {
? HttpServletRequest request = (HttpServletRequest) servletRequest; //类型转换，方便后面调用getSession等方法
? HttpServletResponse response = (HttpServletResponse) servletResponse; //类型转换
?
? HttpSession session = request.getSession(); //取当前请求对应的会话
? if(sessionKey == null)
? {
? filterChain.doFilter(request, response); //放行
? return;
? }
? if((!checkRequestURIIntNotFilterList(request)) && session.getAttribute(sessionKey) == null)
? { //如果本URL必须处理，同时其会话中又没有sessionKey记号，则拦截这些请求，重定向到指定URL
? response.sendRedirect(request.getContextPath() + redirectURL);
? return;
? }
? filterChain.doFilter(servletRequest, servletResponse); //如果上面的检查通过，则放行
? }
?
? public void destroy()
? {
? notCheckURLList.clear();
? }
?
? private boolean checkRequestURIIntNotFilterList(HttpServletRequest request) //判断当前请求是否属于可放行之列
? {
? String uri = request.getServletPath() + (request.getPathInfo() == null ? "" : request.getPathInfo());
? return notCheckURLList.contains(uri);
? }
?
? public void init(FilterConfig filterConfig) throws ServletException
? {
? this.filterConfig = filterConfig;
? redirectURL = filterConfig.getInitParameter("redirectURL"); //将重定向目标URL配置信息读入
? sessionKey = filterConfig.getInitParameter("checkSessionKey"); //将是否过滤的配置信息读入
?
? String notCheckURLListStr = filterConfig.getInitParameter("notCheckURLList"); //将可忽略的URL配置信息读入
?
? if(notCheckURLListStr != null)
? {
? StringTokenizer st = new StringTokenizer(notCheckURLListStr, ";"); //可忽略的URL配置时用;分隔
? notCheckURLList.clear();
? while(st.hasMoreTokens())
? {
? notCheckURLList.add(st.nextToken());
? }
? }
? }
?}
程序不短。
希望能帮到你。
