单机限流的几种方式

(34条消息) 单机限流的几种方式_阳光甚好的博客-CSDN博客

(34条消息) 单机/分布式限流-漏桶/令牌桶/滑动窗口/redis/nginx/sentinel_单机版限流_让火车在天上飞的博客-CSDN博客

/**

• 原子计数限流方式
• 简单粗暴的限流方式，没有平滑处理，需要根据场景使用
  */
  public class AtomicLimit {
  private AtomicInteger requestCount=new AtomicInteger(0); public void doRequest(String threadName){
  try {
  if (requestCount.incrementAndGet() > 10) {
  System.out.println(threadName + “请求过多请稍后重试”);
  } else {
  System.out.println(threadName + “您的请求已经处理”);
  try {
  Thread.sleep(1000);
  } catch (InterruptedException e) {
  e.printStackTrace();
  }
  //mark 正常业务逻辑处理结束
  }
  }finally {
  requestCount.decrementAndGet();
  }
  }

/**

• 利用信号量方式限流
  */
  public class ExcutorSignal {
  public static void main(String[] args) {
  ExecutorService exec = Executors.newFixedThreadPool(20);
  //只能5个线程同时访问
  final Semaphore semp = new Semaphore(5);
  for (int i = 0; i < 20; i++) {
  final int taskNo = i;
  Runnable run = new Runnable() {
  @Override
  public void run() {
  try {
  semp.acquire();//获取许可
  String name = Thread.currentThread().getName();
  System.out.println(“开始” + name + “_” + taskNo);
  Thread.sleep((long) (Math.random() * 10000));
  semp.release();//访问完后释放
  } catch (InterruptedException e) {
  e.printStackTrace();
  }
  }
  };
  exec.execute(run);
  }
  }
  }

/**

• 令牌桶，主要限制流入
• 限流，多的请求直接拒绝
• 可以针对方法级别配置
  */
  public class TrafficShapper {
  private RateLimiter rateLimiter = RateLimiter.create(10);
  public void doRequest(String threadName) {
  boolean isAcquired = rateLimiter.tryAcquire(1, 3000L, TimeUnit.MICROSECONDS);//rateLimiter.tryAcquire();
  if (isAcquired) {
  System.out.println(threadName + “:调用成功”);
  } else {
  System.out.println(threadName + “:当前调用人数过多，请稍后重试”);
  }
  } public static void main(String[] args) {
  final TrafficShapper shapper = new TrafficShapper();
  final CountDownLatch latch = new CountDownLatch(1);
  final Random random = new Random(10);
  for (int i = 0; i < 20; i++) {
  final int finalT = i;
  Thread t = new Thread(new Runnable() {
  @Override
  public void run() {
  try {
  latch.await();
  int sleepTime = random.nextInt(1000);
  Thread.sleep(sleepTime);
  shapper.doRequest(“t-” + finalT);
  } catch (InterruptedException e) {
  e.printStackTrace();
  }
  }
  });
  t.start();
  }
  latch.countDown();
  }

}

CountDownLatch latch=new CountDownLatch(1);//mark 保证线程同一时刻启动
latch.await();
latch.countDown();//当前计数为0则不执行操作，当计数从>0变成0后，所有线程同时启动