java 并发之流量控制实例

实现一个流控程序。控制客户端每秒调用某个远程服务不超过N次，客户端是会多线程并发调用，需要一个轻量简洁的实现，大家看看下面的一个实现，然后可以自己写一个实现。

import java.util.Date; 
 
import java.util.concurrent.ExecutorService; 
 
import java.util.concurrent.Executors; 
 
import java.util.concurrent.Semaphore; 
 
import java.util.concurrent.TimeUnit; 
 
public class Test { 
 
    final static int MAX_QPS = 10; 
 
    final static Semaphore semaphore = new Semaphore(MAX_QPS); 
 
    public static void main (String ... args) throws Exception { 
 
        Executors.newScheduledThreadPool(1).scheduleAtFixedRate(new Runnable() { 
 
            @Override 
 
            public void run() { 
 
                semaphore.release(MAX_QPS/2); 
 
            } 
 
        }, 1000, 500, TimeUnit.MILLISECONDS); 
 
        //lots of concurrent calls:100 * 1000 
        ExecutorService pool = Executors.newFixedThreadPool(100); 
 
        for (int i=100;i>0;i--) { 
 
            final int x = i; 
 
            pool.submit(new Runnable() { 
 
                @Override 
 
                public void run() { 
 
                    for (int j=1000;j>0;j--) { 
 
                        semaphore.acquireUninterruptibly(1); 
                        remoteCall(x, j); 
 
                    } 
 
                } 
 
            }); 
 
        } 
 
        pool.shutdown(); 
 
        pool.awaitTermination(1, TimeUnit.HOURS); 
 
        System.out.println("DONE"); 
    } 
 
    private static void remoteCall(int i, int j) { 
        System.out.println(String.format("%s - %s: %d %d",new Date(), 
            Thread.currentThread(), i, j)); 
    } 
 
}