RateLimiter 从概念上来讲,速率限制器会在可配置的速率下分配许可证。如果必要的话,每个acquire() 会阻塞当前线程直到许可证可用后获取该许可证。一旦获取到许可证,不需要再释放许可证。
校对注:RateLimiter使用的是一种叫令牌桶的流控算法,RateLimiter会按照一定的频率往桶里扔令牌,线程拿到令牌才能执行,比如你希望自己的应用程序QPS不要超过1000,那么RateLimiter设置1000的速率后,就会每秒往桶里扔1000个令牌。
public class APP{
RateLimiter rateLimiter = RateLimiter.create(10);
public void doPay(String name) {
if (rateLimiter.tryAcquire()) {
System.out.println(name + "支付成功");
} else {
System.out.println(name + "支付失败请求繁忙,请稍后重试");
}
}
public static void main(String[] args) throws InterruptedException {
APP app = new APP();
CountDownLatch countDownLatch = new CountDownLatch(1);
Random random = new Random(10);
for (int i = 0; i < 20; i++) {
final int fi = i;
Thread t = new Thread(() -> {
try {
countDownLatch.await();
Thread.sleep(random.nextInt(1000));
app.doPay("Thread-" + fi + "");
} catch (InterruptedException e) {
e.printStackTrace();
}
});
t.start();
}
countDownLatch.countDown();
}
}