https://blog.csdn.net/qq_37228713/article/details/81662119?utm_source=blogxgwz0
1.編寫一個過濾器：
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;
/**
* 自定義過濾器，用來判斷IP訪問次數是否超限
* 如果前台用戶訪問網站的頻率過快（達到超過50次/秒），則判定該ip惡意刷新操作，
* 限制該IP的訪問，1小時后自己解除限制
*
* @author wukaikai
*
*/
@WebFilter(urlPatterns="/*")
public class IpFilter implements Filter{
/**
* 默認限制時間（單位：ms）
*/
private static final long LIMITED_TIME_MILLIS = 60 * 60 * 1000;
/**
* 用戶連續訪問最高閥值，超過該值則認定為惡意操作的IP，進行限制
*/
private static final int LIMIT_NUMBER = 50;
/**
* 用戶訪問最小安全時間，在該時間內如果訪問次數大於閥值，則記錄為惡意IP，否則視為正常訪問
*/
private static final int MIN_SAFE_TIME = 5000;
private FilterConfig config;
@Override
public void init(FilterConfig filterConfig) throws ServletException {
this.config = filterConfig; //設置屬性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();
// 獲取限制IP存儲器：存儲被限制的IP信息
Map<String, Long> limitedIpMap = (Map<String, Long>) context.getAttribute("limitedIpMap");
// 過濾受限的IP
filterLimitedIpMap(limitedIpMap);
// 獲取用戶IP
String ip = Ipsettings.getRemoteHost(request);
System.err.println("ip:"+ip);
// 判斷是否是被限制的IP，如果是則跳到異常頁面
if (isLimitedIP(limitedIpMap, ip)) {
long limitedTime = limitedIpMap.get(ip) - System.currentTimeMillis();
// 剩余限制時間(用為從毫秒到秒轉化的一定會存在些許誤差，但基本可以忽略不計)
request.setAttribute("remainingTime", ((limitedTime / 1000) + (limitedTime % 1000 > 0 ? 1 : 0)));
//request.getRequestDispatcher("/error/overLimitIP").forward(request, response);
System.err.println("ip訪問過於頻繁："+ip);
//response.setCharacterEncoding("gb2312"); //設置輸出內容編碼格式
// response.reset();
// response.setCharacterEncoding("utf-8"); //設置輸出內容編碼格式
// PrintWriter out = response.getWriter();
// out.println("<b>由於您訪問過於頻繁，被系統自動認定為機器人。1個小時自動解除</b>");、
return;
}
// 獲取IP存儲器
Map<String, Long[]> ipMap = (Map<String, Long[]>) context.getAttribute("ipMap");
// 判斷存儲器中是否存在當前IP，如果沒有則為初次訪問，初始化該ip
// 如果存在當前ip，則驗證當前ip的訪問次數
// 如果大於限制閥值，判斷達到閥值的時間，如果不大於[用戶訪問最小安全時間]則視為惡意訪問，跳轉到異常頁面
if (ipMap.containsKey(ip)) {
Long[] ipInfo = ipMap.get(ip);
ipInfo[0] = ipInfo[0] + 1;
System.out.println("當前第[" + (ipInfo[0]) + "]次訪問");
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訪問過於頻繁："+ip);
request.getRequestDispatcher("/error/overLimitIP").forward(request, response);
return;
} else {
initIpVisitsNumber(ipMap, ip);
}
}
} else {
initIpVisitsNumber(ipMap, ip);
System.out.println("您首次訪問該網站");
}
context.setAttribute("ipMap", ipMap);
chain.doFilter(request, response);
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
/**
* @Description 過濾受限的IP，剔除已經到期的限制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) {
// 沒有被限制
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;
}
/**
* 初始化用戶訪問次數和訪問時間
*
* @param ipMap
* @param ip
*/
private void initIpVisitsNumber(Map<String, Long[]> ipMap, String ip) {
Long[] ipInfo = new Long[2];
ipInfo[0] = 0L;// 訪問次數
ipInfo[1] = System.currentTimeMillis();// 初次訪問時間
ipMap.put(ip, ipInfo);
}
}
2. 創建一個監聽器：需要初始化倆個容器：
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存儲器
Map<String, Long[]> ipMap = new HashMap<String, Long[]>();
context.setAttribute("ipMap", ipMap);
// 限制IP存儲器：存儲被限制的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啟動類里面添加以上監聽器和過濾器的掃描包路徑：
@ServletComponentScan(basePackages="com.solian.web")
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原文鏈接：https://blog.csdn.net/qq_37228713/java/article/details/81662119