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This article mainly introduces "how SpringBoot limits the number of interface requests within a certain period of time". In daily operation, it is believed that many people have doubts about how SpringBoot limits the number of interface requests within a certain period of time. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods, hoping to help you answer "how SpringBoot limits the number of interface requests in a certain period of time". Next, please follow the editor to study!

Knowledge to be used: annotations, AOP, ExpiringMap (mapping with validity)

We can customize the annotations and add them to our interface. Define an aspect, and the execution method goes to ExpiringMap to query the number of requests made by the IP within a specified period of time. If the number of requests exceeds, the request fails directly.

Dependency that needs to be used

Org.springframework.boot spring-boot-starter-aop 2.1.5.RELEASE net.jodah expiringmap 0.5.8

Custom annotation @ LimitRequest

@ Documented@Target (ElementType.METHOD) / / indicates that the annotation can only be placed on top of the method @ Retention (RetentionPolicy.RUNTIME) public @ interface LimitRequest {long time () default 6000; / / limit time unit: millisecond int count () default 1; / / number of requests allowed}

Custom AOP

@ Aspect@Componentpublic class LimitRequestAspect {private static ConcurrentHashMap book = new ConcurrentHashMap () / / define the pointcut / / have all methods annotated with @ LimitRequest execute the facet method @ Pointcut ("@ annotation (limitRequest)") public void excudeService (LimitRequest limitRequest) {} @ Around ("excudeService (limitRequest)") public Object doAround (ProceedingJoinPoint pjp, LimitRequest limitRequest) throws Throwable {/ / get the request object RequestAttributes ra = RequestContextHolder.getRequestAttributes (); ServletRequestAttributes sra = (ServletRequestAttributes) ra HttpServletRequest request = sra.getRequest (); / / get the Map object, if not, return the default value / / the first parameter is key, and the second parameter is the default value ExpiringMap uc = book.getOrDefault (request.getRequestURI (), ExpiringMap.builder (). VariableExpiration (). Build ()); Integer uCount = uc.getOrDefault (request.getRemoteAddr (), 0) If (uCount > = limitRequest.count ()) {/ / exceeds the number of times and does not execute the target method return "number of API requests exceeded" } else if (uCount = = 0) {/ / set valid time / / * * Expires entries based on when they were last accessed * / / ACCESSED,// / * * Expires entries based on when they were created * / CREATED; uc.put (request.getRemoteAddr (), uCount + 1, ExpirationPolicy.CREATED, limitRequest.time (), TimeUnit.MILLISECONDS) on the first request } else {/ / does not exceed the number of times, record plus a uc.put (request.getRemoteAddr (), uCount + 1);} book.put (request.getRequestURI (), uc); / / the value of result is the return value of the intercepted method Object result = pjp.proceed (); return result;}}

The first static Map is multithreaded safe Map (ConcurrentHashMap), whose key is the url of the interface, and its value is a multithreaded safe Map (ExpiringMap) with valid key-value pairs.

The key of ExpiringMap is the ip address of the request, and value is the number of times it has been requested.

For more information on how to use ExpiringMap, please see: https://github.com/jhalterman/expiringmap

Finally, add @ LimitRequest to the method.

At this point, the study on "how SpringBoot limits the number of interface requests in a certain period of time" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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