封裝RateLimiter 令牌桶算法

自定義註解封裝RateLimiter.實例:

 

@RequestMapping("/myOrder") @ExtRateLimiter(value = 10.0, timeOut = 500) public String myOrder() throws InterruptedException {            System.out.println("myOrder");            return "SUCCESS"; }

 

自定義註解

@Target(value = ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME) public @interface ExtRateLimiter {       double value();         long timeOut(); }

 

編寫AOP

@Aspect @Component public class RateLimiterAop {       // 存放接口是否已經存在       private static ConcurrentHashMap<String, RateLimiter> rateLimiterMap = new ConcurrentHashMap<String, RateLimiter>();         @Pointcut("execution(public * com.it.api.*.*(..))")       public void rlAop() {       }         @Around("rlAop()")       public Object doBefore(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {            MethodSignature signature = (MethodSignature) proceedingJoinPoint.getSignature();            // 使用Java反射技術獲取方法上是否有@ExtRateLimiter註解類            ExtRateLimiter extRateLimiter = signature.getMethod().getDeclaredAnnotation(ExtRateLimiter.class);            if (extRateLimiter == null) {                  // 正常執行方法                  Object proceed = proceedingJoinPoint.proceed();                  return proceed;            }            // ############獲取註解上的參數 配置固定速率 ###############            // 獲取配置的速率            double value = extRateLimiter.value();            // 獲取等待令牌等待時間            long timeOut = extRateLimiter.timeOut();            RateLimiter rateLimiter = getRateLimiter(value, timeOut);            // 判斷令牌桶獲取token 是否超時            boolean tryAcquire = rateLimiter.tryAcquire(timeOut, TimeUnit.MILLISECONDS);            if (!tryAcquire) {                  serviceDowng();                  return null;            }            // 獲取到令牌,直接執行..            Object proceed = proceedingJoinPoint.proceed();            return proceed;         }         // 獲取RateLimiter對象       private RateLimiter getRateLimiter(double value, long timeOut) {            // 獲取當前URL            ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();            HttpServletRequest request = attributes.getRequest();            String requestURI = request.getRequestURI();            RateLimiter rateLimiter = null;            if (!rateLimiterMap.containsKey(requestURI)) {                  // 開啓令牌通限流                  rateLimiter = RateLimiter.create(value); // 獨立線程                  rateLimiterMap.put(requestURI, rateLimiter);            } else {                  rateLimiter = rateLimiterMap.get(requestURI);            }            return rateLimiter;       }         // 服務降級       private void serviceDowng() throws IOException {            // 執行服務降級處理            System.out.println("執行降級方法,親,服務器忙！請稍後重試!");            ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();            HttpServletResponse response = attributes.getResponse();            response.setHeader("Content-type", "text/html;charset=UTF-8");            PrintWriter writer = response.getWriter();            try {                  writer.println("執行降級方法,親,服務器忙！請稍後重試!");            } catch (Exception e) {              } finally {                  writer.close();            }         }         public static void main(String[] args) {            // 使用Java反射技術獲取方法上是否有@ExtRateLimiter註解類            ExtRateLimiter extRateLimiter = IndexController.class.getClass().getAnnotation(ExtRateLimiter.class);            System.out.println(extRateLimiter);       }   }

運行效果

@RequestMapping("/myOrder") @ExtRateLimiter(value = 10.0, timeOut = 500) public String myOrder() throws InterruptedException {            System.out.println("myOrder");            return "SUCCESS"; }