The use of thread pools and encapsulation of ThreadPoolTaskExecutor in the Spring framework

I have written a lot of information before, but they are all organized by myself and have not been made public. If you are interested, you can look at the information I have organized in the code cloud.

However, the above information is just remembered, and it is not well categorized and sorted out. I will slowly organize it and put it in the blog when I have time. Only by constantly sorting out and sorting out can we continuously deepen memory and improve

Using thread pools in Spring

org.springframework.scheduling.concurrent

ThreadPoolTaskExecutor

public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
		implements AsyncListenableTaskExecutor, SchedulingTaskExecutor

We can see that the ExecutorConfigurationSupport class is inherited

public abstract class ExecutorConfigurationSupport extends CustomizableThreadFactory
		implements BeanNameAware, InitializingBean, DisposableBean

Implementing the three interfaces of BeanNameAware, InitializingBean and DisposableBean is mainly to do some initialization and destruction resource processing operations

Initialization operation:

/**
	 * Calls {@code initialize()} after the container applied all property values.
	 * @see #initialize()
	 */
	@Override
	public void afterPropertiesSet() {
		initialize();
	}

	/**
	 * Set up the ExecutorService.
	 */
	public void initialize() {
		if (logger.isInfoEnabled()) {
			logger.info("Initializing ExecutorService " + (this.beanName != null ? " '" + this.beanName + "'" : ""));
		}
		if (!this.threadNamePrefixSet && this.beanName != null) {
			setThreadNamePrefix(this.beanName + "-");
		}
		this.executor = initializeExecutor(this.threadFactory, this.rejectedExecutionHandler);
	}

	/**
	 * Create the target {@link java.util.concurrent.ExecutorService} instance.
	 * Called by {@code afterPropertiesSet}.
	 * @param threadFactory the ThreadFactory to use
	 * @param rejectedExecutionHandler the RejectedExecutionHandler to use
	 * @return a new ExecutorService instance
	 * @see #afterPropertiesSet()
	 */
	protected abstract ExecutorService initializeExecutor(
			ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler);

There is an abstract method used to initialize the executor

Implementation in ThreadPoolTaskExecutor:

@Override
	protected ExecutorService initializeExecutor(
			ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {

		BlockingQueue<Runnable> queue = createQueue(this.queueCapacity);

		ThreadPoolExecutor executor;
		if (this.taskDecorator != null) {
			executor = new ThreadPoolExecutor(
					this.corePoolSize, this.maxPoolSize, this.keepAliveSeconds, TimeUnit.SECONDS,
					queue, threadFactory, rejectedExecutionHandler) {
				@Override
				public void execute(Runnable command) {
					Runnable decorated = taskDecorator.decorate(command);
					if (decorated != command) {
						decoratedTaskMap.put(decorated, command);
					}
					super.execute(decorated);
				}
			};
		}
		else {
			executor = new ThreadPoolExecutor(
					this.corePoolSize, this.maxPoolSize, this.keepAliveSeconds, TimeUnit.SECONDS,
					queue, threadFactory, rejectedExecutionHandler);

		}

		if (this.allowCoreThreadTimeOut) {
			executor.allowCoreThreadTimeOut(true);
		}

		this.threadPoolExecutor = executor;
		return executor;
	}

Here we can see that is new a ThreadPoolExecutor

destroy operation

@Override
	public void destroy() {
		shutdown();
	}

	/**
	 * Perform a shutdown on the underlying ExecutorService.
	 * @see java.util.concurrent.ExecutorService#shutdown()
	 * @see java.util.concurrent.ExecutorService#shutdownNow()
	 */
	public void shutdown() {
		if (logger.isInfoEnabled()) {
			logger.info("Shutting down ExecutorService" + (this.beanName != null ? " '" + this.beanName + "'" : ""));
		}
		if (this.executor != null) {
			if (this.waitForTasksToCompleteOnShutdown) {
				this.executor.shutdown();
			}
			else {
				for (Runnable remainingTask : this.executor.shutdownNow()) {
					cancelRemainingTask(remainingTask);
				}
			}
			awaitTerminationIfNecessary(this.executor);
		}
	}

We can see that the shutdown of ExecutorService is mainly used to process some resources

Inherit the CustomizableThreadFactory class and customize the rules for new thread name

public CustomizableThreadFactory(String threadNamePrefix) {
		super(threadNamePrefix);
	}


	@Override
	public Thread newThread(Runnable runnable) {
		return createThread(runnable);
	}

specific thread execution

@Override
	public void execute(Runnable task) {
		Executor executor = getThreadPoolExecutor();
		try {
			executor.execute(task);
		}
		catch (RejectedExecutionException ex) {
			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
		}
	}

	@Override
	public void execute(Runnable task, long startTimeout) {
		execute(task);
	}

	@Override
	public Future<?> submit(Runnable task) {
		ExecutorService executor = getThreadPoolExecutor();
		try {
			return executor.submit(task);
		}
		catch (RejectedExecutionException ex) {
			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
		}
	}

	@Override
	public <T> Future<T> submit(Callable<T> task) {
		ExecutorService executor = getThreadPoolExecutor();
		try {
			return executor.submit(task);
		}
		catch (RejectedExecutionException ex) {
			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
		}
	}

Summarize

It is recommended to use ThreadPoolTaskExecutor in the Spring project, which has done a lot of encapsulation of ThreadPoolExecutor and is easy to use. Implementation of ThreadFactory

It is recommended to use ThreadPoolExecutor in non-Spring projects, which can deepen the understanding of thread pools

The following are some implementations of concurrent processing under the org.springframework.scheduling.concurrent package. You can learn more about it when you have time.