Whenever you expose a web service / api endpoint, you need to implement a rate limiter to prevent abuse of the service (DOS attacks).
Implement a RateLimiter Class with an isAllow method. Every request comes in with a unique clientID, deny a request if that client has made more than 100 requests in the past second.
1 public class RateLimiter { 2 private final Map<String, LinkedList<Long>> clientHitMap = new HashMap<>(); 3 private final int REQUEST_LIMIT = 3; 4 private final long TIME_LIMIT = 1000L; 5 6 public boolean isAllow(String client_id) { 7 LinkedList<Long> list = clientHitMap.get(client_id); 8 long curTime = System.currentTimeMillis(); 9 if (list == null) { 10 clientHitMap.put(client_id, new LinkedList<Long>()); 11 } 12 while (!list.isEmpty() && curTime - list.peek() >= TIME_LIMIT) { 13 list.poll(); 14 } 15 if (list.size() < REQUEST_LIMIT) { 16 list.offer(curTime); 17 return true; 18 } 19 return false; 20 } 21 }
原文：https://www.cnblogs.com/beiyeqingteng/p/11148969.html