JAVA多线程 Semaphore 应用

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

public class SemaphoreTest {

	public static void main(String[] args) {

		// 线程池
		ExecutorService exec = Executors.newCachedThreadPool();
		// 只能5个线程同时访问
		final Semaphore semp = new Semaphore(5);
		// 模拟20个客户端访问
		for (int index = 0; index < 20; index++) {
			final int NO = index;
			Runnable run = new Runnable() {
				public void run() {
					try {
						// 获取许可
						semp.acquire();
						System.out.println("Accessing: " + NO);
						TimeUnit.SECONDS.sleep(2L);
						// 访问完后，释放
						semp.release();
						System.out.println("----------------- " + semp.availablePermits());
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			};
			exec.execute(run);
		}
		// 退出线程池
		exec.shutdown();
	}
}

 参考：http://www.cnblogs.com/whgw/archive/2011/09/29/2195555.html

评论

1 楼 bo_hai 2014-06-27  

今天再来复习一下。