我正在开发一些应用程序并使用 ThreadPoolExecutor 来处理各种任务。 ThreadPoolExecutor 在一段时间后卡住。为了在更简单的环境中对此进行模拟,我编写了一个能够模拟该问题的简单代码。
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class MyThreadPoolExecutor {
private int poolSize = 10;
private int maxPoolSize = 50;
private long keepAliveTime = 10;
private ThreadPoolExecutor threadPool = null;
private final ArrayBlockingQueue<Runnable> queue = new ArrayBlockingQueue<Runnable>(
100000);
public MyThreadPoolExecutor() {
threadPool = new ThreadPoolExecutor(poolSize, maxPoolSize,
keepAliveTime, TimeUnit.SECONDS, queue);
threadPool.setRejectedExecutionHandler(new RejectedExecutionHandler() {
@Override
public void rejectedExecution(Runnable runnable,
ThreadPoolExecutor threadPoolExecutor) {
System.out
.println("Execution rejected. Please try restarting the application.");
}
});
}
public void runTask(Runnable task) {
threadPool.execute(task);
}
public void shutDown() {
threadPool.shutdownNow();
}
public ThreadPoolExecutor getThreadPool() {
return threadPool;
}
public void setThreadPool(ThreadPoolExecutor threadPool) {
this.threadPool = threadPool;
}
public static void main(String[] args) {
MyThreadPoolExecutor mtpe = new MyThreadPoolExecutor();
for (int i = 0; i < 1000; i++) {
final int j = i;
mtpe.runTask(new Runnable() {
@Override
public void run() {
System.out.println(j);
}
});
}
}
}
尝试执行此代码几次。它通常在控制台上打印出数字,当所有线程结束时,它就存在。但有时,它完成了所有任务,然后没有被终止。线程转储如下:
MyThreadPoolExecutor [Java Application]
MyThreadPoolExecutor at localhost:2619 (Suspended)
Daemon System Thread [Attach Listener] (Suspended)
Daemon System Thread [Signal Dispatcher] (Suspended)
Daemon System Thread [Finalizer] (Suspended)
Object.wait(long) line: not available [native method]
ReferenceQueue<T>.remove(long) line: not available
ReferenceQueue<T>.remove() line: not available
Finalizer$FinalizerThread.run() line: not available
Daemon System Thread [Reference Handler] (Suspended)
Object.wait(long) line: not available [native method]
Reference$Lock(Object).wait() line: 485
Reference$ReferenceHandler.run() line: not available
Thread [pool-1-thread-1] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-2] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-3] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-4] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-6] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-8] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-5] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-10] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-9] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [pool-1-thread-7] (Suspended)
Unsafe.park(boolean, long) line: not available [native method]
LockSupport.park(Object) line: not available
AbstractQueuedSynchronizer$ConditionObject.await() line: not available
ArrayBlockingQueue<E>.take() line: not available
ThreadPoolExecutor.getTask() line: not available
ThreadPoolExecutor$Worker.run() line: not available
Thread.run() line: not available
Thread [DestroyJavaVM] (Suspended)
C:\Program Files\Java\jre1.6.0_07\bin\javaw.exe (Jun 17, 2010 10:42:33 AM)
在我的实际应用程序中,ThreadPoolExecutor 线程进入此状态然后停止响应。
问候, 拉维饶
最佳答案
在您的main
方法中,您永远不会调用mtpe.shutdown()
。 ThreadPoolExecutor将尝试无限期地保持其 corePoolSize
Activity 。有时,您很幸运,并且有超过 corePoolSize
个线程处于 Activity 状态,因此每个工作线程都将进入一个条件逻辑分支,允许它在您指定的 10 秒超时期限后终止。然而,正如您所注意到的,有时情况并非如此,因此执行程序中的每个线程都会在 ArrayBlockingQueue.take() 上阻塞。并等待新任务。
另请注意,ExecutorService.shutdown() 之间存在显着差异和 ExecutorService.shutdownNow() .如果您按照包装器实现指示调用 ExecutorService.shutdownNow(),您有时会丢弃一些尚未分配执行的任务。
更新:自从我最初的回答以来,ThreadPoolExecutor
实现已更改,因此原始帖子中的程序永远不会退出。
关于Java ThreadPoolExecutor 在使用 ArrayBlockingQueue 时卡住,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3059222/