如何获取 ExecutorService 当前活动的线程数
我们在做多线程的时候,想要查看下当前线程池有多少活动的线程,如何获取呢?
请看下面做的例子即可得到:
import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadPoolExecutor; /** * @Description 获取线程池中的当前活动线程 * @Author Andy *@Date 2018/6/13 */ public class TestForExecutorServicePool { public static void main(String[] args) { ExecutorService exes = null; try{ exes = Executors.newFixedThreadPool(10); //想线程池中放入三个任务 exes.execute(new Task()); exes.execute(new Task()); exes.execute(new Task()); Thread.sleep(500);//延迟500ms,因为三个任务放入需要时间 //将exes转换为ThreadPoolExecutor,ThreadPoolExecutor有方法 getActiveCount()可以得到当前活动线程数 int threadCount = ((ThreadPoolExecutor)exes).getActiveCount(); System.out.println("1.threadCount===="+threadCount); Thread.sleep(3000); threadCount = ((ThreadPoolExecutor)exes).getActiveCount(); System.out.println("2.threadCount===="+threadCount); exes.execute(new Task()); exes.execute(new Task()); Thread.sleep(500); threadCount = ((ThreadPoolExecutor)exes).getActiveCount(); System.out.println("3.threadCount===="+threadCount); }catch(Exception e){ e.printStackTrace(); }finally{ if(exec!=null){ exes.shutdown(); } } } } class Task implements Runnable{ @Override public void run() { try{ Thread.sleep(3000); }catch(Exception e){ e.printStackTrace(); } } }