public ThreadPoolExecutor(int corePoolSize,int maximumPoolSize,long keepAliveTime,TimeUnit unit,BlockingQueue<Runnable> workQueue,ThreadFactory threadFactory,RejectedExecutionHandler handler); 序號參數名稱參數類型參數含義

1	corePoolSize	int	核心線程池大小
2	maximumPoolSize	int	最大線程池大小
3	keepAliveTime	long	線程最大空閑時間
4	unit	TimeUnit	時間單位
5	workQueue	BlockingQueue	線程等待隊列
6	threadFactory	ThreadFactory	線程創建工廠
7	handler	RejectedExecutionHandler	拒絕策略

下面是一些源代碼的實現：

? ?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();}} ?

我們可以總結出線程池默認的工作行為：

• 不會初始化 corePoolSize 個線程，有任務來了才創建工作線程；

• 當核心線程滿了之后不會立即擴容線程池，而是把任務堆積到工作隊列中；

• 當工作隊列滿了后擴容線程池，一直到線程個數達到 maximumPoolSize 為止；

• 如果隊列已滿且達到了最大線程后還有任務進來，按照拒絕策略處理；

• 當線程數大于核心線程數時，線程等待 keepAliveTime 后還是沒有任務需要處理的話，收縮線程到核心線程數。

了解這個策略，有助于我們根據實際的容量規劃需求，為線程池設置合適的初始化參數。當然，我們也可以通過一些手段來改變這些默認工作行為，比如：

• 聲明線程池后立即調用 prestartAllCoreThreads 方法，來啟動所有核心線程；

• 傳入 true 給 allowCoreThreadTimeOut 方法，來讓線程池在空閑的時候同樣回收核心線程。

不知道你有沒有想過：Java 線程池是先用工作隊列來存放來不及處理的任務，滿了之后再擴容線程池。當我們的工作隊列設置的很大時，最大線程數這個參數顯得沒有意義，因為隊列很難滿，或者到滿的時候再去擴容線程池已經于事無補了。

?

那么，我們有沒有辦法讓線程池更激進一點，優先開啟更多的線程，而把隊列當成一個后備方案呢？

下面我們自己實現一個ThreadPoolExecutor，重寫某些方法。

public class MyThreadPoolExecutor extends ThreadPoolExecutor { ?/*** 構造方法** @param corePoolSize ? 核心線程數* @param maximumPoolSize 最大線程數* @param keepAliveTime ? 非核心線程數保留時長* @param unit ? ? ? ? ? 非核心線程數保留時長單位* @param blockQueueSize 阻塞隊列長度*/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()); ?} ?/*** 自定義阻塞隊列** @param <Runnable>*/static class ExtremeBlockQueue<Runnable> extends LinkedBlockingQueue<Runnable> {public ExtremeBlockQueue(int capacity) {super(capacity);} ?/*** 覆蓋默認的offer方法，觸發拒絕策略執行** @param e* @return*/@Overridepublic boolean offer(Runnable e) {if (size() == 0) {return super.offer(e);} else {return false;}} ?} ?/*** 自定義拒絕策略*/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;}}} }

我們創建一個自定義線程池

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

通過這種機制，當我將任務提交到隊列時，ThreadPoolExecutor將：

最初將線程數擴展到核心大小（此處為1）。

將其提供給隊列。如果隊列為空，它將排隊等待由現有線程處理。

如果隊列中已經有1個或多個元素，offer(...)將返回false。

如果返回false，則按比例擴大池中的線程數量，直到達到最大數量（此處為50）。

如果達到最大值，則調用 RejectedExecutionHandler

在RejectedExecutionHandler隨后會將任務到隊列通過FIFO順序交給第一個可用線程處理。

盡管在上面的示例代碼中，隊列是無界的，但是您也可以將其定義為有界隊列。例如，如果將容量添加到1000，LinkedBlockingQueue則它將：

將線程放大到最大

然后排隊直到完成1000個任務

然后阻塞，直到隊列可用為止。

?

我們還可以使用一個最簡單的方法，將核心線程大小和最大線程大小設置為相同的值，并使用允許從池中刪除核心線程allowCoreThreadTimeOut(true)。

?

下面我們寫一個demo演示一下：

我們創建一個Spring項目，用戶在瀏覽器調用該方法：

? ?@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();} ?/*** 定時任務每秒打印當前線程池的狀態** @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輸出：

[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

可以看到線程池的線程數量會先從0增加到5，然后當線程數到達最大線程數時，后面的線程會進入到隊列中排隊等待

總結

以上是生活随笔為你收集整理的如何在队列排队之前让ThreadPoolExecutor将线程增加到最大数量的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。