ThreadPoolTaskExecutor遇到的坑

在利用org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor实现请求的慢处理时，我的配置中核心线程数为5，最大线程数为10，但是代码中创建了8个队列放在线程池中，假如我用id去hash取模，得到队列集合下标，从队列集合中队列，此时就会出现8个队列中，每个队列都有数据，但只有前5个队列中的请求被处理，后3个队列的请求被搁置。
因此，配置线程池的线程最少数量时，一定要大于等于自己创建的队列数量。

<bean id="deviceBindExecutor" name="deviceBindExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
    <!-- 线程池维护线程的最少数量 -->
    <property name="corePoolSize" value="5" />
    <!-- 允许的空闲时间 -->
    <property name="keepAliveSeconds" value="200" />
    <!-- 线程池维护线程的最大数量 -->
    <property name="maxPoolSize" value="10" />
    <!-- 缓存队列 -->
    <property name="queueCapacity" value="10" />
    <!-- 对拒绝task的处理策略 -->
    <property name="rejectedExecutionHandler">
        <bean class="java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy" />
    </property>
</bean>

代码实现如下：

/** 
 * 懒汉式单例可以实现传参的单例初始化
 */
public class RequestProcessorThreadPool {

	private volatile static RequestProcessorThreadPool instance = null;
	private RequestProcessorThreadPool() {
	}
	private RequestProcessorThreadPool(ApplicationContext applicationContext) {
		RequestQueue requestQueue = RequestQueue.getInstance();

		ThreadPoolTaskExecutor threadPool = (ThreadPoolTaskExecutor) applicationContext.getBean("deviceBindExecutor");

		/** 
		 * 给线程池中加入任务队列
		 */
		for (int i = 0; i < 8; i++) {
			ArrayBlockingQueue<Request> queue = new ArrayBlockingQueue<Request>(100);
			requestQueue.addQueue(queue);
			threadPool.submit(new RequestProcessorThread(queue));
		}
	}

	public static RequestProcessorThreadPool getInstance(ApplicationContext applicationContext) {
		if (instance == null) {
			synchronized (RequestProcessorThreadPool.class) {
				if (instance == null) {
					instance = new RequestProcessorThreadPool(applicationContext);
				}
			}
		}
		return instance;
	}
}

/** 
 * 请求队列
 */
public class RequestQueue {

	private List<ArrayBlockingQueue<Request>> queues = new ArrayList<ArrayBlockingQueue<Request>>();

	private RequestQueue() {
	}
	private static class Singleton {

		private static RequestQueue requestQueue = null;
		static {
			requestQueue = new RequestQueue();
		}
		public static RequestQueue getInstance() {
			return requestQueue;
		}
	}

	public static RequestQueue getInstance() {
		return Singleton.getInstance();
	}

	/**
	 * 添加队列到集合
	 */
	public void addQueue(ArrayBlockingQueue<Request> queue) {
		queues.add(queue);
	}

	/**
	 * 队列集合的大小
	 */
	public int queueSize() {
		return queues.size();
	}

	/**
	 * 根据集合下表获取队列
	 */
	public ArrayBlockingQueue<Request> getQueue(int index) {
		return queues.get(index);
	}

}

ThreadPoolTaskExecutor遇到的坑

猜你喜欢