listener
public void contextInitialized(ServletContextEvent sce) { ServletContext context = sce.getServletContext(); //counts:IP+访问次数（一次回话记一次） HashMap<String,Integer> counts = new HashMap<String,Integer>(); context.setAttribute("map", counts); Integer totalcounts = 0;//各个IP总访问次数 context.setAttribute("total", totalcounts); }filter
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest req = (HttpServletRequest) request; String client = req.getRemoteAddr(); HttpSession s = req.getSession(); ServletContext application = req.getServletContext(); Map<String,Integer> counts = (Map<String, Integer>) application.getAttribute("map"); System.out.println("访问是否是新会话： "+s.isNew()); Integer totalcounts = (Integer) application.getAttribute("total"); if(counts.containsKey(client)){ //新会话，访问次数加一 if(s.isNew()){ Integer times = counts.get(client); counts.put(client, times+1); } }else{ application.setAttribute("total", totalcounts+1); counts.put(client, 1); } Set<Entry<String, Integer>> entry = counts.entrySet(); for (Entry<String, Integer> entry2 : entry) { System.out.print(entry2.getKey()+" "); System.out.println(entry2.getValue()); } totalcounts = (Integer) application.getAttribute("total"); System.out.println("总访问IP数： "+totalcounts); System.out.println("======================================"); chain.doFilter(request, response); }