1.编写一个过滤器：
package com.solian.web.filter;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.solian.web.util.Ipsettings;
/**
* 自定义过滤器，用来判断IP访问次数是否超限
* 如果前台用户访问网站的频率过快（达到超过50次/秒），则判定该ip恶意刷新操作，
* 限制该IP的访问，1小时后自己解除限制
*
* @author wukaikai
*
*/
@WebFilter(urlPatterns="/*")
public class IpFilter implements Filter{
/**
* 默认限制时间（单位：ms）
*/
private static final long LIMITED_TIME_MILLIS = 60 * 60 * 1000;
/**
* 用户连续访问最高阀值，超过该值则认定为恶意操作的IP，进行限制
*/
private static final int LIMIT_NUMBER = 50;
/**
* 用户访问最小安全时间，在该时间内如果访问次数大于阀值，则记录为恶意IP，否则视为正常访问
*/
private static final int MIN_SAFE_TIME = 5000;
private FilterConfig config;
@Override
public void init(FilterConfig filterConfig) throws ServletException {
this.config = filterConfig; //设置属性filterConfig
}
/* (non-Javadoc)
* @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
@SuppressWarnings("unchecked")
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
ServletContext context = config.getServletContext();
// 获取限制IP存储器：存储被限制的IP信息
Map<String, Long> limitedIpMap = (Map<String, Long>) context.getAttribute("limitedIpMap");
// 过滤受限的IP
filterLimitedIpMap(limitedIpMap);
// 获取用户IP
String ip = Ipsettings.getRemoteHost(request);
System.err.println("ip:"+ip);
// 判断是否是被限制的IP，如果是则跳到异常页面
if (isLimitedIP(limitedIpMap, ip)) {
long limitedTime = limitedIpMap.get(ip) - System.currentTimeMillis();
// 剩余限制时间(用为从毫秒到秒转化的一定会存在些许误差，但基本可以忽略不计)
request.setAttribute("remainingTime", ((limitedTime / 1000) + (limitedTime % 1000 > 0 ? 1 : 0)));
//request.getRequestDispatcher("/error/overLimitIP").forward(request, response);
System.err.println("ip访问过于频繁："+ip);
//response.setCharacterEncoding("gb2312"); //设置输出内容编码格式
// response.reset();
// response.setCharacterEncoding("utf-8"); //设置输出内容编码格式
// PrintWriter out = response.getWriter();
// out.println("<b>由于您访问过于频繁，被系统自动认定为机器人。1个小时自动解除</b>");、
return;
}
// 获取IP存储器
Map<String, Long[]> ipMap = (Map<String, Long[]>) context.getAttribute("ipMap");
// 判断存储器中是否存在当前IP，如果没有则为初次访问，初始化该ip
// 如果存在当前ip，则验证当前ip的访问次数
// 如果大于限制阀值，判断达到阀值的时间，如果不大于[用户访问最小安全时间]则视为恶意访问，跳转到异常页面
if (ipMap.containsKey(ip)) {
Long[] ipInfo = ipMap.get(ip);
ipInfo[0] = ipInfo[0] + 1;
System.out.println("当前第[" + (ipInfo[0]) + "]次访问");
if (ipInfo[0] > LIMIT_NUMBER) {
Long ipAccessTime = ipInfo[1];
Long currentTimeMillis = System.currentTimeMillis();
if (currentTimeMillis - ipAccessTime <= MIN_SAFE_TIME) {
limitedIpMap.put(ip, currentTimeMillis + LIMITED_TIME_MILLIS);
request.setAttribute("remainingTime", LIMITED_TIME_MILLIS);
System.err.println("ip访问过于频繁："+ip);
request.getRequestDispatcher("/error/overLimitIP").forward(request, response);
return;
} else {
initIpVisitsNumber(ipMap, ip);
}
}
} else {
initIpVisitsNumber(ipMap, ip);
System.out.println("您首次访问该网站");
}
context.setAttribute("ipMap", ipMap);
chain.doFilter(request, response);
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
/**
* @Description 过滤受限的IP，剔除已经到期的限制IP
* @param limitedIpMap
*/
private void filterLimitedIpMap(Map<String, Long> limitedIpMap) {
if (limitedIpMap == null) {
return;
}
Set<String> keys = limitedIpMap.keySet();
Iterator<String> keyIt = keys.iterator();
long currentTimeMillis = System.currentTimeMillis();
while (keyIt.hasNext()) {
long expireTimeMillis = limitedIpMap.get(keyIt.next());
if (expireTimeMillis <= currentTimeMillis) {
keyIt.remove();
}
}
}
/**
* @Description 是否是被限制的IP
* @param limitedIpMap
* @param ip
* @return true : 被限制 | false : 正常
*/
private boolean isLimitedIP(Map<String, Long> limitedIpMap, String ip) {
if (limitedIpMap == null || ip == null) {
// 没有被限制
return false;
}
Set<String> keys = limitedIpMap.keySet();
Iterator<String> keyIt = keys.iterator();
while (keyIt.hasNext()) {
String key = keyIt.next();
if (key.equals(ip)) {
// 被限制的IP
return true;
}
}
return false;
}
/**
* 初始化用户访问次数和访问时间
*
* @param ipMap
* @param ip
*/
private void initIpVisitsNumber(Map<String, Long[]> ipMap, String ip) {
Long[] ipInfo = new Long[2];
ipInfo[0] = 0L;// 访问次数
ipInfo[1] = System.currentTimeMillis();// 初次访问时间
ipMap.put(ip, ipInfo);
}
}
2. 创建一个监听器：需要初始化俩个容器：
package com.solian.web.listener;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@WebListener
public class MyApplicationListener implements ServletContextListener {
private Logger logger = LoggerFactory.getLogger(MyApplicationListener.class);
@Override
public void contextInitialized(ServletContextEvent sce) {
logger.info("liting: contextInitialized");
System.err.println("MyApplicationListener初始化成功");
ServletContext context = sce.getServletContext();
// IP存储器
Map<String, Long[]> ipMap = new HashMap<String, Long[]>();
context.setAttribute("ipMap", ipMap);
// 限制IP存储器：存储被限制的IP信息
Map<String, Long> limitedIpMap = new HashMap<String, Long>();
context.setAttribute("limitedIpMap", limitedIpMap);
logger.info("ipmap："+ipMap.toString()+";limitedIpMap:"+limitedIpMap.toString()+"初始化成功。。。。。");
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// TODO Auto-generated method stub
}
}
3.需要在springboot启动类里面添加以上监听器和过滤器的扫描包路径：
@ServletComponentScan(basePackages="com.solian.web")