public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory,RejectedExecutionHandler handler);
序号 参数名称 参数类型 参数含义
1 corePoolSize int 核心线程池大小
2 maximumPoolSize int 最大线程池大小
3 keepAliveTime long 线程最大空闲时间
4 unit TimeUnit 时间单位
5 workQueue BlockingQueue 线程等待队列
6 threadFactory ThreadFactory 线程创建工厂
7 handler RejectedExecutionHandler 拒绝策略

下面是一些源代码的实现：

    public void execute(Runnable command) {if (command == null)throw new NullPointerException();
​int c = ctl.get();if (workerCountOf(c) < corePoolSize) {if (addWorker(command, true))return;c = ctl.get();}if (isRunning(c) && workQueue.offer(command)) {int recheck = ctl.get();if (! isRunning(recheck) && remove(command))reject(command);else if (workerCountOf(recheck) == 0)addWorker(null, false);}else if (!addWorker(command, false))reject(command);}

ArrayBlockingQueue.offer(E e)

    public boolean offer(E e) {checkNotNull(e);final ReentrantLock lock = this.lock;lock.lock();try {if (count == items.length)return false;else {enqueue(e);return true;}} finally {lock.unlock();}}
​

我们可以总结出线程池默认的工作行为：

  • 不会初始化 corePoolSize 个线程，有任务来了才创建工作线程；

  • 当核心线程满了之后不会立即扩容线程池，而是把任务堆积到工作队列中；

  • 当工作队列满了后扩容线程池，一直到线程个数达到 maximumPoolSize 为止；

  • 如果队列已满且达到了最大线程后还有任务进来，按照拒绝策略处理；

  • 当线程数大于核心线程数时，线程等待 keepAliveTime 后还是没有任务需要处理的话，收缩线程到核心线程数。

了解这个策略，有助于我们根据实际的容量规划需求，为线程池设置合适的初始化参数。当然，我们也可以通过一些手段来改变这些默认工作行为，比如：

  • 声明线程池后立即调用 prestartAllCoreThreads 方法，来启动所有核心线程；

  • 传入 true 给 allowCoreThreadTimeOut 方法，来让线程池在空闲的时候同样回收核心线程。

不知道你有没有想过：Java 线程池是先用工作队列来存放来不及处理的任务，满了之后再扩容线程池。当我们的工作队列设置的很大时，最大线程数这个参数显得没有意义，因为队列很难满，或者到满的时候再去扩容线程池已经于事无补了。

那么，我们有没有办法让线程池更激进一点，优先开启更多的线程，而把队列当成一个后备方案呢？

下面我们自己实现一个ThreadPoolExecutor，重写某些方法。

public class MyThreadPoolExecutor extends ThreadPoolExecutor {
​/*** 构造方法** @param corePoolSize    核心线程数* @param maximumPoolSize 最大线程数* @param keepAliveTime   非核心线程数保留时长* @param unit            非核心线程数保留时长单位* @param blockQueueSize  阻塞队列长度*/public MyThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, int blockQueueSize) {super(corePoolSize, maximumPoolSize, keepAliveTime, unit, new MyThreadPoolExecutor.ExtremeBlockQueue<>(blockQueueSize), Executors.defaultThreadFactory(), new MyThreadPoolExecutor.ExtremePolicy());
​}
​/*** 自定义阻塞队列** @param <Runnable>*/static class ExtremeBlockQueue<Runnable> extends LinkedBlockingQueue<Runnable> {public ExtremeBlockQueue(int capacity) {super(capacity);}
​/*** 覆盖默认的offer方法，触发拒绝策略执行** @param e* @return*/@Overridepublic boolean offer(Runnable e) {if (size() == 0) {return super.offer(e);} else {return false;}}
​}
​/*** 自定义拒绝策略*/static class ExtremePolicy implements RejectedExecutionHandler {@Overridepublic void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {try {executor.getQueue().put(r);if (executor.isShutdown()) {throw new RejectedExecutionException("Task " + r + " rejected from " + executor);}} catch (InterruptedException e) {Thread.currentThread().interrupt();return;}}}
}

我们创建一个自定义线程池

ExecutorService threadPool = new MyThreadPoolExecutor(1, 50, 5, TimeUnit.SECONDS,  Integer.MAX_VALUE);

通过这种机制，当我将任务提交到队列时，ThreadPoolExecutor将：

  1. 最初将线程数扩展到核心大小（此处为1）。

  2. 将其提供给队列。如果队列为空，它将排队等待由现有线程处理。

  3. 如果队列中已经有1个或多个元素，offer(...)将返回false。

  4. 如果返回false，则按比例扩大池中的线程数量，直到达到最大数量（此处为50）。

  5. 如果达到最大值，则调用 RejectedExecutionHandler

  6. 在RejectedExecutionHandler随后会将任务到队列通过FIFO顺序交给第一个可用线程处理。

尽管在上面的示例代码中，队列是无界的，但是您也可以将其定义为有界队列。例如，如果将容量添加到1000，LinkedBlockingQueue则它将：

  1. 将线程放大到最大

  2. 然后排队直到完成1000个任务

  3. 然后阻塞，直到队列可用为止。

我们还可以使用一个最简单的方法，将核心线程大小和最大线程大小设置为相同的值，并使用允许从池中删除核心线程allowCoreThreadTimeOut(true)。

下面我们写一个demo演示一下：

我们创建一个Spring项目，用户在浏览器调用该方法：

    @GetMapping("right")public int right() throws InterruptedException {AtomicInteger atomicInteger = new AtomicInteger();ThreadPoolExecutor threadPool = new MyThreadPoolExecutor(2, 5,5, TimeUnit.SECONDS,10);printStats(threadPool);IntStream.rangeClosed(1, 20).forEach(i -> {try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {e.printStackTrace();}int id = atomicInteger.incrementAndGet();try {threadPool.submit(() -> {log.info("{} started", id);try {TimeUnit.SECONDS.sleep(10);} catch (InterruptedException e) {}log.info("{} finished", id);});} catch (Exception ex) {log.error("error submitting task {}", id, ex);atomicInteger.decrementAndGet();}});
​TimeUnit.SECONDS.sleep(60);return atomicInteger.intValue();}
​/*** 定时任务每秒打印当前线程池的状态** @param threadPool*/private void printStats(ThreadPoolExecutor threadPool) {Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate(() -> {log.info("=========================");log.info("Pool Size: {}", threadPool.getPoolSize());log.info("Active Threads: {}", threadPool.getActiveCount());log.info("Number of Tasks Completed: {}", threadPool.getCompletedTaskCount());log.info("Number of Tasks in Queue: {}", threadPool.getQueue().size());
​log.info("=========================");}, 0, 1, TimeUnit.SECONDS);}

下面是日志的一部分输出：

[16:33:43.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:43.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 0
[16:33:43.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 0
[16:33:43.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:43.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 0
[16:33:43.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:44.453] [pool-5-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 1 started
[16:33:44.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:44.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 1
[16:33:44.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 1
[16:33:44.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:44.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 0
[16:33:44.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:45.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:45.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 2
[16:33:45.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 2
[16:33:45.453] [pool-5-thread-2] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 2 started
[16:33:45.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:45.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 0
[16:33:45.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:46.456] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:46.456] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 2
[16:33:46.456] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 2
[16:33:46.457] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:46.457] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 0
[16:33:46.457] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:47.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:47.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 2
[16:33:47.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 2
[16:33:47.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:47.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 1
[16:33:47.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:47.457] [pool-5-thread-3] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 4 started
[16:33:48.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:48.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 3
[16:33:48.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 3
[16:33:48.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:48.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 1
[16:33:48.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:48.457] [pool-5-thread-4] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 5 started
[16:33:49.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:49.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 4
[16:33:49.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 4
[16:33:49.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:49.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 1
[16:33:49.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:49.458] [pool-5-thread-5] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 6 started
[16:33:50.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:50.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:50.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:50.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:50.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 1
[16:33:50.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:51.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:51.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:51.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:51.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:51.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 2
[16:33:51.453] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:52.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:52.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:52.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:52.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:52.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 3
[16:33:52.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:53.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:53.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:53.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:53.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 0
[16:33:53.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 4
[16:33:53.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:54.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:54.454] [pool-5-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 1 finished
[16:33:54.454] [pool-5-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 3 started
[16:33:54.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:54.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:54.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 1
[16:33:54.456] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 4
[16:33:54.456] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:55.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:55.454] [pool-5-thread-2] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 2 finished
[16:33:55.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:55.454] [pool-5-thread-2] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 7 started
[16:33:55.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:55.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 2
[16:33:55.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 4
[16:33:55.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:56.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:56.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:56.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:56.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 2
[16:33:56.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 5
[16:33:56.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:57.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:57.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:57.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:57.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 2
[16:33:57.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 6
[16:33:57.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:57.457] [pool-5-thread-3] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 4 finished
[16:33:57.457] [pool-5-thread-3] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 8 started
[16:33:58.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:58.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:58.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:58.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 3
[16:33:58.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 6
[16:33:58.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:58.458] [pool-5-thread-4] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 5 finished
[16:33:58.458] [pool-5-thread-4] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 9 started
[16:33:59.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:33:59.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:33:59.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:33:59.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 4
[16:33:59.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 6
[16:33:59.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:33:59.458] [pool-5-thread-5] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 6 finished
[16:33:59.458] [pool-5-thread-5] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 10 started
[16:34:00.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:34:00.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:34:00.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:34:00.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 5
[16:34:00.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 6
[16:34:00.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:34:01.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:34:01.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:34:01.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:34:01.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 5
[16:34:01.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 7
[16:34:01.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:34:02.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:34:02.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:34:02.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:34:02.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 5
[16:34:02.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 8
[16:34:02.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:34:03.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:34:03.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:34:03.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:34:03.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 5
[16:34:03.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 9
[16:34:03.454] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:34:04.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:34:04.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:34:04.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:34:04.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 5
[16:34:04.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 10
[16:34:04.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:28  ] - =========================
[16:34:04.455] [pool-5-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 3 finished
[16:34:04.455] [pool-5-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 11 started
[16:34:05.454] [pool-5-thread-2] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:95  ] - 7 finished
[16:34:05.454] [pool-5-thread-2] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:90  ] - 12 started
[16:34:05.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:22  ] - =========================
[16:34:05.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:23  ] - Pool Size: 5
[16:34:05.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:24  ] - Active Threads: 5
[16:34:05.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:25  ] - Number of Tasks Completed: 7
[16:34:05.455] [pool-6-thread-1] [INFO ] [o.g.t.c.t.t.ThreadPoolOOMController:26  ] - Number of Tasks in Queue: 8

可以看到线程池的线程数量会先从0增加到5，然后当线程数到达最大线程数时，后面的线程会进入到队列中排队等待

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