Posted on 2010-10-15 20:28
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场景：需要启动多线程处理事情，而在所有事情做完之后，需要修改系统状态；那么如何判断所有线程（事情）都做完了呢？这就需要判断所有当前运行的线程状态了。
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
/**
* 测试监控类
*
* @author
*
*/
public class WatchThread {
/**
* 测试函数
*
* @throws InterruptedException
*/
public void testThread() throws InterruptedException {
int threadNum = 10;
// 初始化countDown
CountDownLatch threadSignal = new CountDownLatch(threadNum);
// 创建固定长度的线程池
Executor executor = Executors.newFixedThreadPool(threadNum);
for (int i = 0; i < threadNum; i++) { // 开threadNum个线程
Runnable task = new TestThread(threadSignal);
// 执行
executor.execute(task);
}
threadSignal.await(); // 等待所有子线程执行完
// do work
System.out.println(Thread.currentThread().getName() + "+++++++结束.");
}
/**
* 测试函数
*/
public static void main(String[] args) throws InterruptedException {
WatchThread test = new WatchThread();
test.testThread();
}
/**
*
* @author jill
*
*/
private class TestThread implements Runnable {
private CountDownLatch threadsSignal;
public TestThread(CountDownLatch threadsSignal) {
this.threadsSignal = threadsSignal;
}
public void run() {
System.out.println(Thread.currentThread().getName() + "开始
");
// do shomething
System.out.println("开始了线程：：：：" + threadsSignal.getCount());
// 线程结束时计数器减1
threadsSignal.countDown();
System.out.println(Thread.currentThread().getName() + "结束. 还有"
+ threadsSignal.getCount() + " 个线程");
}
}
}