如何在队列排队之前让ThreadPoolExecutor将线程增加到最大数量
public ThreadPoolExecutor(int corePoolSize,
int maximumPoolSize,
long keepAliveTime,
TimeUnit unit,
BlockingQueue 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
*/
static class ExtremeBlockQueue extends LinkedBlockingQueue {
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
*/
@Override
public 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 {
@Override
public 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：
-
最初将线程数扩展到核心大小（此处为1）。
-
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。
-
如果队列中已经有1个或多个元素，
offer(...)将返回false。 -
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）。
-
如果达到最大值，则调用
RejectedExecutionHandler -
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：
-
将线程放大到最大
-
然后排队直到完成1000个任务
-
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