JavaSemaphore限流实现详解

import java.util.concurrent.Semaphore;

public class RateLimiter {
    // 定义一个信号量，允许最多3个线程并发执行
    private final Semaphore semaphore = new Semaphore(3);

    public void handleRequest(String requestId) {
        if (semaphore.tryAcquire()) {  // 尝试获取许可
            try {
                System.out.println("请求 " + requestId + " 开始处理");
                Thread.sleep(2000); // 模拟处理时间
                System.out.println("请求 " + requestId + " 处理完成");
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                semaphore.release(); // 释放许可
            }
        } else {
            System.out.println("请求 " + requestId + " 被拒绝，超出并发限制");
        }
    }

    public static void main(String[] args) {
        RateLimiter limiter = new RateLimiter();

        // 模拟10个并发请求
        for (int i = 1; i  limiter.handleRequest(Thread.currentThread().getName())).start();
            try {
                Thread.sleep(300); // 模拟请求间隔
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }
}