防止用户恶意刷新过滤器

为了防止用户对网站页面刷新过于频繁,需要对这种恶意操作进行判断并且屏蔽.虽然公司要有这样的一个功能,但是我觉得太没有必要了.只要你服务器够好,你何必需要这样的功能呢?下面是全部代码(仅供大家参考,我觉得实际意义不是很大):

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.f139.frame.util.NetUtil;

public class RefreshFilter implements Filter {

    private static final Map<String, Integer> ipcount = new ConcurrentHashMap<String, Integer>();

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        try {
            filter((HttpServletRequest) request,
                    (HttpServletResponse) response, chain);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    private void filter(HttpServletRequest request,
            HttpServletResponse response, FilterChain chain)
            throws IOException, ServletException, InterruptedException {
        response.setCharacterEncoding("UTF-8");
        request.setCharacterEncoding("UTF-8");
        // 获得用户的IP地址,根据用户IP地址来判断此用户是否刷新过于频繁
        String userIP = NetUtil.getIpAddr(request);
        Cache cache = Cache.getInstance();
        cache.increment(userIP);
        if (cache.isUpCount(userIP)) {
            Integer count = ipcount.get(userIP);
            if (count != null) {
                ipcount.put(userIP, count + 1);
                System.out.println(ipcount.get(userIP));
            } else {
                count = 0;
                ipcount.put(userIP, count + 1);
            }
            if (ipcount.get(userIP) > 3) {
                response.getWriter().println("很抱歉,您操作过于频繁.");
                //403页面
                ((HttpServletResponse) response)
                        .sendError(HttpServletResponse.SC_FORBIDDEN);
                /**
                 * 在这里可以使用quartz工作调度对map进行定时的清理,时被禁止的用户可以重新访问本页面
                 */
                return;
            }
            response.getWriter().println("操作频繁，请3秒后再试");
            return;
        }
        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {

    }

    @Override
    public void init(FilterConfig config) throws ServletException {

    }

    private static class Cache {

        private static final ConcurrentHashMap<String, CopyOnWriteArrayList<Long>> map = new ConcurrentHashMap<String, CopyOnWriteArrayList<Long>>();
        // 用户闲置时间
        private static final long EXPIRE_TIME = 1000 * 5L;
        // 用户频繁刷新次数上限,第六次就禁止刷新 www.zzzyk.com
        private static final int MAX_COUNT = 5;

        private static final Cache cache = new Cache();

        private Cache() {
            new Thread(new ClearCacheThread()).start();
        }

        public static Cache getInstance() {
            return cache;
        }

        // 每次刷新页面的时候就在缓存中增加一个刷新时间点(标识刷新次数)
        public void increment(String key) {
            CopyOnWriteArrayList<Long> list = map.get(key);
            if (list == null) {
                map.put(key, new CopyOnWriteArrayList

补充：综合编程 , 安全编程 ,