Java线程池监控应用

线程池是我们平时开发中使用较多的一种组件，其主要监控点在于池中的线程和阻塞队列中的任务情况。

构建一个线程池

先构建一个基本的线程池，并看看有哪些参数我们可以直接获取到

public class ThreadPoolMonitor {

    private final static Logger log = LoggerFactory.getLogger(ThreadPoolMonitor.class);

    private static final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(2, 4, 0,
            TimeUnit.SECONDS, new LinkedBlockingQueue<>(100),
            new ThreadFactoryBuilder().setNameFormat("my_thread_pool_%d").build());

    public static void main(String[] args) {
        log.info("Pool Size: " + threadPool.getPoolSize());
        log.info("Active Thread Count: " + threadPool.getActiveCount());
        log.info("Task Queue Size: " + threadPool.getQueue().size());
        log.info("Completed Task Count: " + threadPool.getCompletedTaskCount());
    }
}

[main] INFO thread.ThreadPoolMonitor - Pool Size: 0
[main] INFO thread.ThreadPoolMonitor - Active Thread Count: 0
[main] INFO thread.ThreadPoolMonitor - Task Queue Size: 0
[main] INFO thread.ThreadPoolMonitor - Completed Task Count: 0
[main] INFO thread.ThreadPoolMonitor - Completed Task Count: 0

定时监控

加上定时一秒一次的任务来监控，线程池的使用情况

public class ThreadPoolMonitor {

    private final static Logger log = LoggerFactory.getLogger(ThreadPoolMonitor.class);

    private static final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(2, 4, 0,
            TimeUnit.SECONDS, new LinkedBlockingQueue<>(100),
            new ThreadFactoryBuilder().setNameFormat("my_thread_pool_%d").build(), new ThreadPoolExecutor.DiscardOldestPolicy());

    public static void main(String[] args) {
    	// 每秒输出一次线程池的使用情况
        printThreadPoolState();
        // 模拟任务执行
        IntStream.rangeClosed(0, 20).forEach(i -> {
        	// 每100毫秒，执行一个任务
            try {
                TimeUnit.MILLISECONDS.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            // 每个处理一个任务耗时5秒
            threadPool.submit(() -> {
                try {
                    TimeUnit.SECONDS.sleep(5);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            });
        });
    }

    private static void printThreadPoolState() {
        Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate(() -> {
            log.info("Pool Size: " + threadPool.getPoolSize());
            log.info("Active Thread Count: " + threadPool.getActiveCount());
            log.info("Task Queue Size: " + threadPool.getQueue().size());
            log.info("Completed Task Count: " + threadPool.getCompletedTaskCount());
            log.info("---------------");
        }, 0, 1, TimeUnit.SECONDS);
    }
}